GNU Emacs NEWS -- history of user-visible changes.

Copyright (C) 2022-2024 Free Software Foundation, Inc.
See the end of the file for license conditions.

Please send Emacs bug reports to 'bug-gnu-emacs@gnu.org'.
If possible, use 'M-x report-emacs-bug'.

This file is about changes in Emacs version 30.

See file HISTORY for a list of GNU Emacs versions and release dates.
See files NEWS.29, NEWS.28, ..., NEWS.18, and NEWS.1-17 for changes
in older Emacs versions.

You can narrow news to a specific version by calling 'view-emacs-news'
with a prefix argument or by typing 'C-u C-h C-n'.


* Installation Changes in Emacs 30.1

+++
** Emacs has been ported to the Android operating system.
This requires Emacs to be compiled on another computer.  The Android
NDK, SDK, and a suitable Java compiler must also be installed.

See the file 'java/INSTALL' for more details.

---
** Native compilation is now enabled by default.
'configure' will enable the Emacs Lisp native compiler, so long as
libgccjit is present and functional on the system.  To disable native
compilation, configure Emacs with the option:

    ./configure --with-native-compilation=no

---
** Emacs now defaults to ossaudio library for sound on NetBSD and OpenBSD.
Previously configure used ALSA libraries if installed on the
system when configured '--with-sound=yes' (which is the default), with
fallback to libossaudio.  The libossaudio library included with the
base system is now used even if ALSA is found to avoid relying on
external packages and to resolve potential incompatibilities between
Linux and BSD versions of ALSA.  Use '--with-sound=alsa' to build with
ALSA on these operating systems instead.

---
** Native JSON support is now always available; libjansson is no longer used.
No external library is required.  The '--with-json' configure option has
been removed.  'json-available-p' now always returns non-nil and is only
kept for compatibility.


* Startup Changes in Emacs 30.1

** On GNU/Linux, Emacs is now the default application for 'org-protocol'.
Org mode provides a way to quickly capture bookmarks, notes, and links
using 'emacsclient':

    emacsclient "org-protocol://store-link?url=URL&title=TITLE"

Previously, users had to manually configure their GNU/Linux desktop
environment to open 'org-protocol' links in Emacs.  These links should
now open in Emacs automatically, as the "emacsclient.desktop" file now
arranges for Emacs to be the default application for the 'org-protocol'
URI scheme.  See the Org mode manual, Info node "(org) Protocols" for
more details.


* Incompatible Changes in Emacs 30.1

** Mouse wheel events should now always be 'wheel-up/down/left/right'.
At those places where the old 'mouse-4/5/6/7' events could still occur
(i.e. X11 input in the absence of XInput2, and 'xterm-mouse-mode'),
we remap them to the corresponding 'wheel-up/down/left/right' event,
according to the new variable 'mouse-wheel-buttons'.
The old variables 'mouse-wheel-up-event', 'mouse-wheel-down-event',
'mouse-wheel-left-event', and 'mouse-wheel-right-event' are thereby
obsolete.

** Tree-Sitter modes are now declared as submodes of the non-TS modes.
In order to help the use of those Tree-Sitter modes, they are now
declared to have the corresponding non-Tree-Sitter mode as an
additional parent.
This way, things like `.dir-locals.el` settings, and YASnippet
collections of snippets automatically apply to the new Tree-Sitter modes.

Note that those modes still do not inherit from the non-TS mode, so
configuration settings installed via mode hooks are not affected.

+++
** URL now never sends user email addresses in HTTP requests.
Emacs never sent email addresses by default, but it used to be
possible to customize 'url-privacy-level' so that the users email
address was sent along in HTTP requests.  This feature has now been
removed, as it was considered more dangerous than useful.  RFC 9110
(§ 10.1.2) also recommends against it.  The user option
'url-personal-mail-address' is now also obsolete.

To send an email address in the header of individual HTTP requests,
see the variable 'url-request-extra-headers'.

+++
** 'completion-auto-help' now affects 'icomplete-in-buffer'.
Previously, 'completion-auto-help' mostly affected only minibuffer
completion.  Now, if 'completion-auto-help' has the value 'lazy', then
Icomplete's in-buffer display of possible completions will only appear
after the 'completion-at-point' command has been invoked twice, and if
'completion-auto-help' is nil, then Icomplete's in-buffer display is
completely suppressed.  Thus, if you use 'icomplete-in-buffer', ensure
'completion-auto-help' is not customized to 'lazy' or nil.

+++
** The "*Completions*" buffer now always accompanies 'icomplete-in-buffer'.
Previously, it was not consistent whether the "*Completions*" buffer would
appear when using 'icomplete-in-buffer'.  Now the "*Completions*" buffer
and Icomplete's in-buffer display of possible completions always
appear together.  If you would prefer to see only Icomplete's
in-buffer display, and not the "*Completions*" buffer, you can add this
to your init:

    (advice-add 'completion-at-point :after #'minibuffer-hide-completions)


* Changes in Emacs 30.1

** 'describe-function' now shows the type of the function object.
The text used to say things like "car is is a built-in function"
whereas it now says "car is a primitive-function" where "primitive-function"
is the symbol returned by `cl-type-of` and you can click on it to get
information about that type.

** 'advice-remove' is now an interactive command.
When called interactively, 'advice-remove' now prompts for an advised
function to the advice to remove.

** Emacs now supports Unicode Standard version 15.1.

** Network Security Manager

+++
*** The Network Security Manager now warns about 3DES by default.
This cypher is no longer recommended owing to a major vulnerability
disclosed in 2016, and its small 112 bit key size.  Emacs now warns
about its use also when 'network-security-level' is set to 'medium'
(the default).  See 'network-security-protocol-checks'.

---
*** The Network Security Manager now warns about <2048 bits in DH key exchange.
Emacs used to warn for Diffie-Hellman key exchanges with prime numbers
smaller than 1024 bits.  Since more servers now support it, this
number has been bumped to 2048 bits.

** Help

*** 'describe-function' shows function inferred type when available.
For native compiled Lisp functions 'describe-function' prints (after
the signature) the automatically inferred function type as well.

---
*** New user option 'describe-bindings-outline-rules'.
This user option controls outline visibility in the output buffer of
'describe-bindings' when 'describe-bindings-outline' is non-nil.

---
*** 'C-h m' ('describe-mode') uses outlining by default.
Set 'describe-mode-outline' to nil to get back the old behavior.

** Outline Mode

+++
*** 'outline-minor-mode' is supported in tree-sitter major modes.
It can be used in all tree-sitter major modes that set either the
variable 'treesit-simple-imenu-settings' or 'treesit-outline-predicate'.

** X selection requests are now handled much faster and asynchronously.
This means it should be less necessary to disable the likes of
'select-active-regions' when Emacs is running over a slow network
connection.

** Emacs now updates invisible frames that are made visible by a compositor.
If an invisible or an iconified frame is shown to the user by the
compositing manager, Emacs will now redisplay such a frame even though
'frame-visible-p' returns nil or 'icon' for it.  This can happen, for
example, as part of preview for iconified frames.

---
** New user option 'menu-bar-close-window'.
When non-nil, selecting "Close" from the "File" menu or clicking
"Close" in the tool bar will result in the current window being
closed, if possible.

+++
** 'write-region-inhibit-fsync' now defaults to t in interactive mode,
as it has in batch mode since Emacs 24.

+++
** New user option 'remote-file-name-inhibit-delete-by-moving-to-trash'.
When non-nil, this option suppresses moving remote files to the local
trash when deleting.  Default is nil.

---
** New user option 'remote-file-name-inhibit-auto-save'.
If this user option is non-nil, 'auto-save-mode' will not auto-save
remote buffers.  The default is nil.

+++
** New user option 'remote-file-name-access-timeout'.
When a positive number, this option limits the call of 'access-file'
for remote files to this number of seconds.  Default is nil.

+++
** New user option 'yes-or-no-prompt'.
This allows the user to customize the prompt that is appended by
'yes-or-no-p' when asking questions.  The default value is
"(yes or no) ".

---
** New face 'display-time-date-and-time'.
This is used for displaying the time and date components of
'display-time-mode'.

---
** New icon images for general use.
Several symbolic icons are added to "etc/images/symbols", including
plus, minus, check-mark, start, etc.

+++
** Tool bars can now be placed on the bottom on more systems.
The 'tool-bar-position' frame parameter can be set to 'bottom' on all
window systems other than Nextstep.

+++
** New global minor mode 'modifier-bar-mode'.
When this minor mode is enabled, buttons representing modifier keys
are displayed along the tool bar.

+++
** "d" in the mode line now indicates that the window is dedicated.
Windows have always been able to be dedicated to a specific buffer;
see 'window-dedicated-p'.  Now the mode line indicates the dedicated
status of a window, with "d" appearing in the mode line if a window is
dedicated and "D" if the window is strongly dedicated.  This indicator
appears before the buffer name, and after the buffer modification and
remote buffer indicators (usually "---" together).

+++
** New command 'toggle-window-dedicated'.
This makes it easy to interactively mark a specific window as
dedicated, so it won't be reused by 'display-buffer'.  This can be
useful for complicated window setups.  It is bound to 'C-x w d'
globally.

---
** New user option 'uniquify-dirname-transform'.
This can be used to customize how buffer names are uniquified, by
making arbitrary transforms on the buffer's directory name (whose
components are used to uniquify buffer names when they clash).  You
can use this to distinguish between buffers visiting files with the
same base name that belong to different projects by using the provided
transform function 'project-uniquify-dirname-transform'.

** 'insert-directory-program' is now a user option.
On *BSD and macOS systems, this user option now defaults to the "gls"
executable, if it exists.  This should remove the need to change its
value when installing GNU coreutils using something like ports or
Homebrew.

+++
** cl-print

+++
*** You can expand the "..." truncation everywhere.
The code that allowed "..." to be expanded in the "*Backtrace*" buffer
should now work anywhere the data is generated by 'cl-print'.

+++
*** The 'backtrace-ellipsis' button is replaced by 'cl-print-ellipsis'.

+++
*** hash-tables' contents can be expanded via the ellipsis.

+++
*** Modes can control the expansion via 'cl-print-expand-ellipsis-function'.

+++
*** New setting 'raw' for 'cl-print-compiled'.
This setting causes byte-compiled functions to be printed in full by
'prin1'.  A button on this output can be activated to disassemble the
function.

+++
*** There is a new chapter in the CL manual documenting cl-print.el.
See the Info node "(cl) Printing".

** Modeline elements can now be right-aligned.
Anything following the symbol 'mode-line-format-right-align' in
'mode-line-format' will be right-aligned.  Exactly where it is
right-aligned to is controlled by the new user option
'mode-line-right-align-edge'.

** Windows

+++
*** New action alist entry 'category' for 'display-buffer'.
If the caller of 'display-buffer' passes '(category . symbol)'
in its 'action' argument, you can match the displayed buffer
by adding '(category . symbol)' to the condition part of
'display-buffer-alist' entries.

+++
*** New action alist entry 'post-command-select-window' for 'display-buffer'.
It specifies whether the window of the displayed buffer should be
selected or deselected at the end of executing the current command.

---
*** User option 'display-comint-buffer-action' is now obsolete.
You can use a '(category . comint)' condition in 'display-buffer-alist'
to match buffers displayed by comint-related commands.  Another
user option 'display-tex-shell-buffer-action' is obsolete too
for which you can use '(category . tex-shell)'.

+++
*** New variable 'window-restore-killed-buffer-windows'.
It specifies how 'set-window-configuration' and 'window-state-put'
should proceed with windows whose buffer was killed after the
corresponding configuration or state was recorded.

*** New variable 'window-point-context-set-function'.
It can be used to set a context for window point in all windows by
'window-point-context-set' before calling 'current-window-configuration'
and 'window-state-get'.  Then later another new variable
'window-point-context-use-function' can be used by
'window-point-context-use' after 'set-window-configuration' and
'window-state-put' to restore positions of window points
according to the context stored in a window parameter.

** Tab Bars and Tab Lines

---
*** New user option 'tab-bar-select-restore-context'.
It uses 'window-point-context-set' to save contexts where
window points were located before switching away from the tab,
and 'window-point-context-use' to restore positions of window
points after switching back to that tab.

---
*** New user option 'tab-bar-select-restore-windows'.
It defines what to do with windows whose buffer was killed
since the tab was last selected.  By default it displays
a placeholder buffer that provides information about the name
of the killed buffer that was displayed in that window.

---
*** New user option 'tab-bar-tab-name-format-functions'.
It can be used to add, remove and reorder functions that change
the appearance of every tab on the tab bar.

---
*** New hook 'tab-bar-tab-post-select-functions'.

---
*** New keymap 'tab-bar-mode-map'.
By default it contains a keybinding 'C-TAB' to switch tabs,
but only when 'C-TAB' is not bound globally.  You can unbind it
if it conflicts with 'C-TAB' in other modes.

+++
** New optional argument for modifying directory-local variables.
The commands 'add-dir-local-variable', 'delete-dir-local-variable' and
'copy-file-locals-to-dir-locals' now take an optional prefix argument,
to enter the file you want to modify.

** Miscellaneous

---
*** New face 'appt-notification' for 'appt-display-mode-line'.
It can be used to customize the look of the appointment notification
displayed on the mode line when 'appt-display-mode-line' is non-nil.

---
*** Emacs now recognizes shebang lines that pass '-S'/'--split-string' to 'env'.
When visiting a script that invokes 'env -S INTERPRETER ARGS...' in
its shebang line, Emacs will now skip over 'env -S' and deduce the
major mode based on the interpreter after 'env -S'.

** Emacs Server and Client

---
*** 'server-eval-args-left' can be used to pop and eval subsequent args.
When '--eval' is passed to emacsclient and Emacs is evaluating each
argument, this variable is set to those arguments not yet evaluated.
It can be used to 'pop' arguments and process them by the function
called in the '--eval' expression, which is useful when those
arguments contain arbitrary characters that otherwise might require
elaborate and error-prone escaping (to protect them from the shell).

+++
** 'recover-file' can show diffs between auto save file and current file.
When answering the prompt with "diff" or "=", it now shows the diffs
between the auto save file and the current file.

---
** 'ffap-lax-url' now defaults to nil.
Previously, it was set to t but this broke remote file name detection.

+++
** Multi-character key echo now ends with a suggestion to use Help.
Customize 'echo-keystrokes-help' to nil to prevent that.

+++
** 'read-passwd' can toggle the visibility of passwords.
Use 'TAB' in the minibuffer to show or hide the password.  Likewise,
there is an icon on the mode-line, which toggles the visibility of the
password when clicking with 'mouse-1'.


* Editing Changes in Emacs 30.1

+++
** New minor mode 'visual-wrap-prefix-mode'.
When enabled, continuation lines displayed for a wrapped long line
will receive a 'wrap-prefix' automatically computed from the line's
surrounding context, such that continuation lines are indented on
display as if they were filled with 'M-q' or similar.  Unlike 'M-q',
the indentation only happens on display, and doesn't change the buffer
text in any way.  The global minor mode
'global-visual-wrap-prefix-mode' enables this minor mode in all
buffers.

(This minor mode is the 'adaptive-wrap' ELPA package renamed and
lightly edited for inclusion in Emacs.)

+++
** New user option 'gud-highlight-current-line'.
When enabled, Gud will visually emphasize the line being executed upon
pauses in the debugee's execution, such as those occasioned by
breakpoints being hit.

---
** New global minor mode 'kill-ring-deindent-mode'.
When enabled, text being saved to the kill ring will be de-indented by
the column number at its start.  For example, saving the entire
function call within:

foo ()
{
  long_function_with_several_arguments (argument_1_compute (),
					argument_2_compute (),
					argument_3_compute ());
}

will save:

long_function_with_several_arguments (argument_1_compute (),
				      argument_2_compute (),
				      argument_3_compute ())

to the kill ring, omitting the two columns of extra indentation that
would otherwise be present in the second and third lines of the
function call.

+++
** Emacs now has better support for touchscreen devices.
Many touch screen gestures are now implemented and translated into
mouse or gesture events, and support for tapping tool bar buttons and
opening menus has been written.  Countless packages, such as Dired and
Custom have been adjusted to better understand touch screen input.

---
** On X, Emacs now supports input methods which perform "string conversion".
This means an input method can now ask Emacs to delete text
surrounding point and replace it with something else, as well as query
Emacs for surrounding text.  If your input method allows you to "undo"
mistaken compositions, this will now work as well.

---
** New command 'kill-matching-buffers-no-ask'.
This works like 'kill-matching-buffers', but without asking for
confirmation.

---
** New user option 'duplicate-region-final-position'.
It controls the placement of point and the region after duplicating a
region with 'duplicate-dwim'.

+++
** New user option 'mouse-prefer-closest-glyph'.
When enabled, clicking or dragging with the mouse will put the point
or start the drag in front of the buffer position corresponding to the
glyph with the closest X coordinate to the click or start of the drag.
In other words, if the mouse pointer is in the right half of a glyph,
point will be put after the buffer position corresponding to that glyph,
whereas if the mouse pointer is in the left half of a glyph, point
will be put in front the buffer position corresponding to that glyph.
By default this is disabled.

** Internationalization

---
*** Users in CJK locales can control width of some non-CJK characters.
Some characters are considered by Unicode as "ambiguous" with respect
to their display width: either "full-width" (i.e. taking 2 columns on
display) or "narrow" (taking 1 column).  The actual width depends on
the fonts used for these characters by Emacs or (for text-mode frames)
by the terminal emulator.  Traditionally, font sets in CJK locales
were set up so as to display these characters as full-width, and thus
Emacs modified the char-width table in those locales to follow suit.
Lately, the tendency is to display these characters as narrow.  The
new user option 'cjk-ambiguous-chars-are-wide' allows users to control
whether Emacs considers these characters as full-width (the default)
or narrow (if the variable is customized to the nil value).

This setting affects the results of 'string-width' and similar
functions in CJK locales.

---
*** New input methods for the Urdu, Pashto, and Sindhi languages.
These languages are spoken in Pakistan and Afghanistan.

---
*** New input method "english-colemak".
This input method supports the Colemak keyboard layout.

*** Additional 'C-x 8' key translations for "æ" and "Æ".
These characters can now be input with 'C-x 8 a e' and 'C-x 8 A E',
respectively, in addition to the existing translations 'C-x 8 / e' and
'C-x 8 / E'.


* Changes in Specialized Modes and Packages in Emacs 30.1

---
** Titdic-cnv
Most of the variables and functions in the file have been renamed to
make sure they all use a 'tit-' namespace prefix.

---
** Trace
In batch mode, tracing now sends the trace to stdout.

+++
** Mwheel
The 'wheel-up/down/left/right' events are now bound unconditionally,
and the 'mouse-wheel-up/down/left/right-event' variables are thus used
only to specify the 'mouse-4/5/6/7' events that might still
happen to be generated by some old packages (or if 'mouse-wheel-buttons'
has been set to nil).

** 'xterm-mouse-mode'
This mode now emits 'wheel-up/down/right/left' events instead of
'mouse-4/5/6/7' events for the mouse wheel.
It uses the new variable 'mouse-wheel-buttons' to decide which button
maps to which wheel event (if any).

** Info

---
*** New user option 'Info-url-alist'.
This user option associates manual names with URLs.  It affects the
'Info-goto-node-web' command.  By default, associations for all
Emacs-included manuals are set.  Further associations can be added for
arbitrary Info manuals.

*** Emacs can now display Info manuals compressed with 'lzip'.
This requires the 'lzip' program to be installed on your system.

+++
** New command 'lldb'.
Run the LLDB debugger, analogous to the 'gud-gdb' command.

** gdb-mi

---
*** Variable order and truncation can now be configured in 'gdb-many-windows'.
The new user option 'gdb-locals-table-row-config' allows users to
configure the order and max length of various properties in the local
variables buffer when using 'gdb-many-windows'.

By default, this user option is set to write the properties in the order:
name, type and value, where the name and type are truncated to 20
characters, and the value is truncated according to the value of
'gdb-locals-value-limit'.

If you want to get back the old behavior, set the user option to the value

    (setopt gdb-locals-table-row-config
            `((type . 0) (name . 0) (value . ,gdb-locals-value-limit)))

---
*** New user option 'gdb-display-io-buffer'.
If this is nil, 'M-x gdb' will neither create nor display a separate
buffer for the I/O of the program being debugged, but will instead
redirect the program's interaction to the GDB execution buffer.  The
default is t, to preserve previous behavior.

** Grep

*** New user option 'grep-use-headings'.
When non-nil, the output of Grep is split into sections, one for each
file, instead of having file names prefixed to each line.  It is
equivalent to the "--heading" option of some tools such as 'git grep'
and 'rg'.  The headings are displayed using the new 'grep-heading'
face.

** Compilation mode

---
*** The 'omake' matching rule is now disabled by default.
This is because it partly acts by modifying other rules which may
occasionally be surprising.  It can be re-enabled by adding 'omake' to
'compilation-error-regexp-alist'.

*** Lua errors and stack traces are now recognized.
Compilation mode now recognizes Lua language errors and stack traces.
Every Lua error is recognized as a compilation error, and every Lua
stack frame is recognized as a compilation info.

** Project

+++
*** New user option 'project-mode-line'.
When non-nil, display the name of the current project on the mode
line.  Clicking 'mouse-1' on the project name pops up the project
menu.  The default value is nil.

*** New user option 'project-file-history-behavior'.
Customizing it to 'relativize' makes commands like 'project-find-file'
and 'project-find-dir' display previous history entries relative to
the current project.

*** New user option 'project-key-prompt-style'.
The look of the key prompt in the project switcher has been changed
slightly.  To get the previous one, set this option to 'brackets'.

*** 'project-try-vc' tries harder to find the responsible VCS.
When 'project-vc-extra-root-markers' is non-nil, and causes a
subdirectory project to be detected which is not a VCS root, we now
additionally traverse the parent directories until a VCS root is found
(if any), so that the ignore rules for that repository are used, and
the file listing's performance is still optimized.

*** New commands 'project-any-command' and 'project-prefix-or-any-command'.
The former is now bound to 'C-x p o' by default.
The latter is designed primarily for use as a value of
'project-switch-commands'.  If instead of a short menu you prefer to
have access to all keys defined inside 'project-prefix-map', as well
as global bindings (to run other commands inside the project root),
you can add this to your init script:

    (setopt project-switch-commands #'project-prefix-or-any-command)

** VC

---
*** Log-Edit buffers now display a tool bar.
This tool bar contains items for committing log entries and editing or
generating log entries, among other editing operations.

---
*** New user option 'vc-git-shortlog-switches'.
This is a string or a list of strings that specifies the Git log
switches for shortlogs, such as the one produced by 'C-x v L'.
'vc-git-log-switches' is no longer used for shortlogs.

---
*** New value 'no-backend' for user option 'vc-display-status'.
With this value only the revision number is displayed on the mode-line.

---
*** Obsolete command 'vc-switch-backend' re-added as 'vc-change-backend'.
The command was previously obsoleted and unbound in Emacs 28.

*** Support for viewing VC change history across renames.
When a fileset's VC change history ('C-x v l') ends at a rename, we
now print the old name(s) and a button which jumps to their history.
Git and Hg are supported.  Naturally, 'vc-git-print-log-follow' should
be nil for this to work (or '--follow' should not be in
'vc-hg-print-log-switches', in Hg's case).  Unlike when the '--follow'
switch is used, commands to see the diff of the old revision ('d'),
check out an old file version ('f') or annotate it right away ('a'),
also work on revisions which precede renames.

---
*** 'vc-annotate' now abbreviates the Git revision in the buffer name.
When using the Git backend, 'vc-annotate' will use an abbreviated
revision identifier in its buffer name.  To restore the previous
behavior, set 'vc-annotate-use-short-revision' to nil.

*** New option 'vc-git-file-name-changes-switches'.
It allows tweaking the thresholds for rename and copy detection.

** Diff mode

---
*** New user option 'diff-refine-nonmodified'.
When this is non-nil, 'diff-refine' will highlight lines that were added
or removed in their entirety (as opposed to modified lines, where some
parts of the line were modified), using the same faces as for
highlighting the words added and removed within modified lines.  The
default value is nil.

+++
*** 'diff-ignore-whitespace-hunk' can now be applied to all hunks.
When called with a non-nil prefix argument,
'diff-ignore-whitespace-hunk' now iterates over all the hunks in the
current diff, regenerating them without whitespace changes.

+++
*** New user option 'diff-ignore-whitespace-switches'.
This allows changing which type of whitespace changes are ignored when
regenerating hunks with 'diff-ignore-whitespace-hunk'.  Defaults to
the previously hard-coded "-b".

*** New command 'diff-apply-buffer' bound to 'C-c RET a'.
It applies the diff in the entire diff buffer and
saves all modified file buffers.

** Isearch and Replace

*** New command 'replace-regexp-as-diff'.
It reads a regexp to search for and a string to replace with, then
displays a buffer with replacements as diffs.  After reviewing the
changes in the output buffer you can apply the replacements as
a patch to the current file buffer.  There are also new commands
'multi-file-replace-regexp-as-diff' that shows as diffs replacements
in a list of specified files, and 'dired-do-replace-regexp-as-diff'
that shows as diffs replacements in the marked files in Dired.

** Dired

---
*** New user option 'dired-movement-style'.
When non-nil, make 'dired-next-line', 'dired-previous-line',
'dired-next-dirline', 'dired-prev-dirline' skip empty lines.
It also controls how to move point when encountering a boundary
(e.g., if every line is visible, invoking 'dired-next-line' at
the last line will move to the first line).  The default is nil.

*** New user option 'dired-filename-display-length'.
It is an integer representing the maximum display length of filenames.
The middle part of a filename whose length exceeds the restriction is
hidden and an ellipsis is displayed instead.  A value of 'window'
means using the right edge of window as the display restriction.  The
default is nil.

*** New user option 'shell-command-guess-functions'.
It defines how to populate a list of commands available
for 'M-!', 'M-&', '!', '&' and the context menu "Open With"
based on marked files in Dired.  Possible backends are
'dired-guess-default', MIME types, XDG configuration
and a universal command such as "open" or "start"
that delegates to the OS.

*** New command 'dired-do-open'.
This command is bound to "Open" in the context menu; it "opens" the
marked or clicked on files according to the OS conventions.  For
example, on systems supporting XDG, this runs 'xdg-open' on the
files.

*** The default value of 'dired-omit-size-limit' was increased.
After performance improvements to omitting in large directories, the new
default value is 300k, up from 100k.  This means 'dired-omit-mode' will
omit files in directories whose directory listing is up to 300 kilobytes
in size.

+++
*** 'dired-listing-switches' handles connection-local values if exist.
This allows to customize different switches for different remote machines.

** Registers

+++
*** New mode of prompting for register names and showing preview.
The new user option 'register-use-preview' can be customized to the
value t or insist to request a different user interface of prompting for
register names and previewing the registers: Emacs will require
confirmation for overwriting the value of a register, and will show
the preview of registers without delay.  You can also customize this
new option to disable the preview completely.

The default value of 'register-use-preview' preserves the behavior of
Emacs 29 and before.  See the Info node "(emacs) Registers" for more
details about the new UI and its variants.

** Ediff

---
*** New user option 'ediff-floating-control-frame'.
If non-nil, try making the control frame be floating rather than tiled.

Many X tiling window managers make the Ediff control frame a tiled
window equal in size to the main Emacs frame, which works poorly.
This option is useful to set if you use such a window manager.

** Buffer Selection

---
*** New user option 'bs-default-action-list'.
You can now configure how to display the "*buffer-selection*" buffer
using this new option.  (Or set 'display-buffer-alist' directly.)

** Eshell

+++
*** New builtin Eshell command 'compile'.
This command runs another command, sending its output to a compilation
buffer when the command would output interactively.  This can be useful
when defining aliases so that they produce a compilation buffer when
appropriate, but still allow piping the output elsewhere if desired.
For more information, see the "(eshell) Built-ins" node in the Eshell
manual.

+++
*** Eshell's 'env' command now supports running commands.
Like in many other shells, Eshell's 'env' command now lets you run a
command passed as arguments to 'env'.  If you pass any initial
arguments of the form 'VAR=VALUE', 'env' will first set 'VAR' to
'VALUE' before running the command.

---
*** Eshell's 'umask' command now supports setting the mask symbolically.
Now, you can pass an argument like "u+w,o-r" to Eshell's 'umask'
command, which will give write permission for owners of newly-created
files and deny read permission for users who are not members of the
file's group.  See the Info node "(coreutils) File permissions" for
more information on this notation.

+++
*** New special reference type '#<marker POSITION BUFFER>'.
This special reference type returns a marker at 'POSITION' in
'BUFFER'.  You can insert it by typing or using the new interactive
command 'eshell-insert-marker'.  You can also insert special
references of any type using the new interactive command
'eshell-insert-special-reference'.  See the "(eshell) Arguments" node
in the Eshell manual for more details.

+++
*** New splice operator for Eshell dollar expansions.
Dollar expansions in Eshell now let you splice the elements of the
expansion in-place using '$@expr'.  This makes it easier to fill lists
of arguments into a command, such as when defining aliases.  For more
information, see the "(eshell) Dollars Expansion" node in the Eshell
manual.

+++
*** You can now splice Eshell globs in-place into argument lists.
By setting 'eshell-glob-splice-results' to a non-nil value, Eshell
will expand glob results in-place as if you had typed each matching
file name individually.  For more information, see the "(eshell)
Globbing" node in the Eshell manual.

+++
*** Eshell now supports negative numbers and ranges for indices.
Now, you can retrieve the last element of a list with '$my-list[-1]'
or get a sublist of elements 2 through 4 with '$my-list[2..5]'.  For
more information, see the "(eshell) Dollars Expansion" node in the
Eshell manual.

+++
*** Eshell commands can now be explicitly-remote (or local).
By prefixing a command name in Eshell with a remote identifier, like
"/ssh:user@remote:whoami", you can now run commands on a particular
host no matter your current directory.  Likewise, you can run a
command on your local system no matter your current directory via
"/:whoami".  For more information, see the "(eshell) Remote Access"
node in the Eshell manual.

+++
*** Eshell's '$UID' and '$GID' variables are now connection-aware.
Now, when expanding '$UID' or '$GID' in a remote directory, the value
is the user or group ID associated with the remote connection.

---
*** Eshell now uses 'field' properties in its output.
In particular, this means that pressing the '<home>' key moves the
point to the beginning of your input, not the beginning of the whole
line.  If you want to go back to the old behavior, add something like
this to your configuration:

    (keymap-set eshell-mode-map "<home>" #'eshell-bol-ignoring-prompt)

This also means you no longer need to adjust 'eshell-prompt-regexp'
when customizing your Eshell prompt.

---
*** You can now properly unload Eshell.
Calling '(unload-feature 'eshell)' no longer signals an error, and now
correctly unloads Eshell and all of its modules.

+++
*** 'eshell-read-aliases-list' is now an interactive command.
After manually editing 'eshell-aliases-file', you can use this command
to load the edited aliases.

+++
*** 'rgrep' is now a builtin command.
Running 'rgrep' in Eshell now uses the Emacs grep facility instead of
calling external rgrep.

+++
*** If a command exits abnormally, the Eshell prompt now shows its exit code.

+++
*** New user option 'eshell-history-append'.
If non-nil, each Eshell session will save history by appending new
entries of that session to the history file rather than overwriting
the file with the whole history of the session.  The default is nil.

** Minibuffer and Completions

*** New commands 'previous-line-completion' and 'next-line-completion'.
Bound to '<up>' and '<down>' arrow keys, respectively, they navigate
the "*Completions*" buffer vertically by lines, wrapping at the
top/bottom when 'completion-auto-wrap' is non-nil.

*** New user option 'minibuffer-visible-completions'.
When customized to non-nil, you can use arrow keys in the minibuffer
to navigate the completions displayed in the "*Completions*" window.
Typing 'RET' selects the highlighted candidate.  'C-g' hides the
completions window.  When the completions window is not visible,
then all these keys have their usual meaning in the minibuffer.
This option is supported for in-buffer completion as well.

*** Selected completion candidates are deselected on typing.
When you type at the minibuffer prompt, the current completion
candidate will be un-highlighted, and point in the "*Completions*" window
will be moved off that candidate.  'minibuffer-choose-completion'
('M-RET') will still choose a previously-selected completion
candidate, but the new command 'minibuffer-choose-completion-or-exit'
(bound to 'RET' by 'minibuffer-visible-completions') will exit with
the minibuffer contents instead.  This deselection behavior can be
controlled with the new user option 'completion-auto-deselect', which
is t by default.

*** New value 'historical' for user option 'completions-sort'.
When 'completions-sort' is set to 'historical', completion candidates
will be first sorted alphabetically, and then re-sorted by their order
in the minibuffer history, with more recent candidates appearing first.

+++
*** 'completion-category-overrides' supports more metadata.
The new supported completion properties are 'cycle-sort-function',
'display-sort-function', 'annotation-function', 'affixation-function',
and 'group-function'.  You can now customize them for any category in
'completion-category-overrides' that will override the properties
defined in completion metadata.

+++
*** 'completion-extra-properties' supports more metadata.
The new supported completion properties are 'category',
'group-function', 'display-sort-function', and 'cycle-sort-function'.

** Pcomplete

---
*** New user option 'pcomplete-remote-file-ignore'.
When this option is non-nil, remote file names are not completed by
Pcomplete.  Packages, like 'shell-mode', could set this in order to
suppress remote file name completion at all.

---
*** Completion for the 'doas' command has been added.
Command completion for 'doas' in Eshell and Shell mode will now work.

** Shell mode

+++
*** New user option 'shell-get-old-input-include-continuation-lines'.
When this user option is non-nil, 'shell-get-old-input' ('C-RET')
includes multiple shell "\" continuation lines from command output.
Default is nil.

** Make mode

*** The Makefile browser is now obsolete.
The command 'makefile-switch-to-browser' command is now obsolete,
together with related commands used in the "*Macros and Targets*"
buffer.  We recommend using an alternative like 'imenu' instead.

** Prog mode

+++
*** New command 'prog-fill-reindent-defun'.
This command either fills a single paragraph in a defun, such as a
docstring, or a comment, or (re)indents the surrounding defun if
point is not in a comment or a string.  It is by default bound to
'M-q' in 'prog-mode' and all its descendants.

** Which Function mode

+++
*** Which Function mode can now display function names on the header line.
The new user option 'which-func-display' allows choosing where the
function name is displayed.  The default is 'mode' to display in the
mode line.  'header' will display in the header line;
'mode-and-header' displays in both the header line and mode line.

** Tramp

+++
*** New connection method "androidsu".
This provides access to system files with elevated privileges granted by
the idiosyncratic 'su' implementations and system utilities customary on
Android.

+++
*** New connection methods "dockercp" and "podmancp".
These are the external methods counterparts of "docker" and "podman".

+++
*** New connection methods "toolbox" and "flatpak".
They allow accessing system containers provided by Toolbox or
sandboxes provided by Flatpak.

+++
*** Connection method "kubernetes" supports now optional container name.
The host name for Kubernetes connections can be of kind [CONTAINER.]POD,
in order to specify a dedicated container.  If there is just the pod
name, the first container in the pod is taken.  The new user options
'tramp-kubernetes-context' and 'tramp-kubernetes-namespace' allow
accessing pods with different context or namespace but the default one.

+++
*** Rename 'tramp-use-ssh-controlmaster-options' to 'tramp-use-connection-share'.
The old name still exists as obsolete variable alias.  This user
option controls now connection sharing for both ssh-based and
plink-based methods.  It allows the values t, nil, and 'suppress'.
The latter suppresses also "ControlMaster" settings in the user's
"~/.ssh/config" file, or connection share configuration in PuTTY
sessions, respectively.

+++
*** New command 'tramp-cleanup-some-buffers'.
It kills only a subset of opened remote buffers, subject to the user
option 'tramp-cleanup-some-buffers-hook'.

+++
*** New command 'inhibit-remote-files'.
This command disables the handling of file names with the special
remote file name syntax.  It should be applied only when remote files
won't be used in this Emacs instance.  It provides a slightly improved
performance of file name handling in Emacs.

+++
*** New macro 'without-remote-files'.
This macro could wrap code which handles local files only.  Due to the
temporary deactivation of remote files, it results in a slightly
improved performance of file name handling in Emacs.

+++
*** New user option 'tramp-completion-multi-hop-methods'.
It contains a list of connection methods for which completion should
be attempted at the end of a multi-hop chain.  This allows completion
candidates to include a list of, for example, containers running on a
remote docker host.

+++
*** New command 'tramp-revert-buffer-with-sudo'.
It reverts the current buffer to visit with "sudo" permissions.  The
buffer must either visit a file, or it must run 'dired-mode'.  Another
method but "sudo" can be configured with user option
'tramp-file-name-with-method'.

---
*** Direct asynchronous processes use 'tramp-remote-path'.
When a direct asynchronous process is invoked, it uses 'tramp-remote-path'
for setting the remote PATH environment variable.

** File Notifications

+++
*** All backends except w32notify detect unmounting of a watched filesystem now.

** EWW

+++
*** 'eww-open-file' can now display the file in a new buffer.
By default, the command reuses the "*eww*" buffer, but if called with
the new argument NEW-BUFFER non-nil, it will use a new buffer instead.
Interactively, invoke 'eww-open-file' with a prefix argument to
activate this behavior.

---
*** 'eww' URL or keyword prompt now has tab completion.
The interactive minibuffer prompt when invoking 'eww' now has support
for tab completion.

+++
*** 'eww' URL and keyword prompt now completes suggested URIs and bookmarks.
The interactive minibuffer prompt when invoking 'eww' now provides
completions from 'eww-suggest-uris'.  'eww-suggest-uris' now includes
bookmark URIs.

+++
*** New command 'eww-copy-alternate-url'.
It copies an alternate link on the page currently visited in EWW into
the kill ring.  Alternate links are optional metadata that HTML pages
use for linking to their alternative representations, such as
translated versions or associated RSS feeds.

+++
*** 'eww-open-in-new-buffer' supports the prefix argument.
When invoked with the prefix argument ('C-u'),
'eww-open-in-new-buffer' will not make the new buffer the current one.
This is useful for continuing reading the URL in the current buffer
when the new URL is fetched.

---
*** History navigation in EWW now works like other browsers.
Previously, when navigating back and forward through page history, EWW
would add a duplicate entry to the end of the history list each time.
This made it impossible to navigate to the "end" of the history list.
Now, navigating through history in EWW simply changes your position in
the history list, allowing you to reach the end as expected.  In
addition, when browsing to a new page from a "historical" one (i.e. a
page loaded by navigating back through history), EWW deletes the history
entries newer than the current page.  To change the behavior when
browsing from "historical" pages, you can customize
'eww-before-browse-history-function'.

+++
*** 'eww-readable' now toggles display of the readable parts of a web page.
When called interactively, 'eww-readable' toggles whether to display
only the readable parts of a page or the full page.  With a positive
prefix argument, it always displays the readable parts, and with a zero
or negative prefix, it always displays the full page.

+++
*** New option 'eww-readable-urls'.
This is a list of regular expressions matching the URLs where EWW should
display only the readable parts by default.  For more details, see
"(eww) Basics" in the EWW manual.

---
*** New option 'eww-readable-adds-to-history'.
When non-nil (the default), calling 'eww-readable' adds a new entry to
the EWW page history.

** go-ts-mode

+++
*** New command 'go-ts-mode-docstring'.
This command adds a docstring comment to the current defun.  If a
comment already exists, point is only moved to the comment.  It is
bound to 'C-c C-d' in 'go-ts-mode'.

** Man mode

+++
*** New user option 'Man-prefer-synchronous-call'.
When this is non-nil, run the 'man' command synchronously rather than
asynchronously (which is the default behavior).

+++
*** New user option 'Man-support-remote-systems'.
This option controls whether the man page is formatted on the remote
system when the current buffer's default-directory is remote.  You can
invoke the 'man' command with a prefix argument to countermand the
value of this option for the current invocation of 'man'.

** DocView

---
*** New face 'doc-view-svg-face'.
This replaces 'doc-view-svg-foreground' and 'doc-view-svg-background'.
If you don't like the colors produced by the default definition of
this new face when DocView displays documents, customize this face to
restore the colors you were used to, or to get colors more to your
liking.

---
*** DocView buffers now display a new tool bar.
This tool bar contains options for searching and navigating within the
document, replacing the incompatible items for incremental search and
editing within the default tool bar displayed in the past.

** Shortdoc

+++
*** New function 'shortdoc-function-examples'.
This function returns examples of use of a given Emacs Lisp function
from the available shortdoc information.

+++
*** New function 'shortdoc-help-fns-examples-function'.
This function inserts into the current buffer examples of use of a
given Emacs Lisp function, which it gleans from the shortdoc
information.  If you want 'describe-function' ('C-h f') to insert
examples of using the function into regular "*Help*" buffers, add the
following to your init file:

    (add-hook 'help-fns-describe-function-functions
              #'shortdoc-help-fns-examples-function)

** Package

---
*** New user option 'package-vc-register-as-project'.
When non-nil, it will automatically register every package as a
project, that you can quickly select using 'project-switch-project'
('C-x p p').

---
*** New user option 'package-vc-allow-build-commands'.
Controls for which packages Emacs runs extra build commands when
installing directly from the package VCS repository.

---
*** New command to start an inferior Emacs loading only specific packages.
The new command 'package-isolate' will start a new Emacs process, as
a sub-process of Emacs where you invoke the command, in a way that
causes the new process to load only some of the installed packages.
The command prompts for the packages to activate in this
sub-process, and is intended for testing Emacs and/or the packages
in a clean environment.

** Flymake

+++
*** New user option 'flymake-show-diagnostics-at-end-of-line'.
When non-nil, Flymake shows summarized descriptions of diagnostics at
the end of the line.  Depending on your preference, this can either be
distracting and easily confused with actual code, or a significant
early aid that relieves you from moving the buffer or reaching for the
mouse to consult an error message.

** Flyspell

*** New user option 'flyspell-check-changes'.
When non-nil, Flyspell mode spell-checks only words that you edited; it
does not check unedited words just because you move point across them.

** JS mode.
The binding 'M-.' has been removed from the major mode keymaps in
'js-mode' and 'js-ts-mode', having it default to the global binding
which calls 'xref-find-definitions'.  If the previous one worked
better for you, use 'define-key' in your init script to bind
'js-find-symbol' to that combination again.

** Json mode.
'js-json-mode' does not derive from 'js-mode' any more so as not
to confuse tools like Eglot or YASnippet into thinking that those
buffers contain Javascript code.

** Python mode

---
*** New user option 'python-indent-block-paren-deeper'.
If non-nil, increase the indentation of the lines inside parens in a
header of a block when they are indented to the same level as the body
of the block:

    if (some_expression
            and another_expression):
        do_something()

instead of:

    if (some_expression
        and another_expression):
        do_something()

*** New user option 'python-interpreter-args'.
This allows the user to specify command line arguments to the non
interactive Python interpreter specified by 'python-interpreter'.

** Scheme mode

Scheme mode now handles regular expression literal #/regexp/ that is
available in some Scheme implementations.
Also, it should now handle nested sexp-comments.

** use-package

+++
*** New ':vc' keyword.
This keyword enables the user to install packages using 'package-vc'.

+++
*** New user option 'use-package-vc-prefer-newest'.
This allows the user to always install the newest commit of a package
when using the ':vc' keyword.

** Gnus

*** The 'nnweb-type' option 'gmane' has been removed.
The gmane.org website is, sadly, down since a number of years with no
prospect of it coming back.  Therefore, it is no longer valid to set
the user option 'nnweb-type' to 'gmane'.

---
*** New user option 'gnus-mode-line-logo'.
This allows the user to either disable the display of any logo or
specify which logo will be displayed as part of the
buffer-identification in the mode-line of Gnus buffers.

** Rmail

---
*** New commands for reading mailing lists.
The new Rmail commands 'rmail-mailing-list-post',
'rmail-mailing-list-unsubscribe', 'rmail-mailing-list-help', and
'rmail-mailing-list-archive' allow, respectively, posting to,
unsubscribing from, requesting help about, and browsing the archives
of, the mailing list from which the current email message was
delivered.

** Dictionary

---
*** New user option 'dictionary-search-interface'.
Controls how the 'dictionary-search' command prompts for and displays
dictionary definitions.  Customize this user option to 'help' to have
'dictionary-search' display definitions in a "*Help*" buffer and
provide dictionary-based minibuffer completion for word selection.

---
*** New user option 'dictionary-read-word-prompt'.
This allows the user to customize the prompt that is used by
'dictionary-search' when asking for a word to search in the
dictionary.

---
*** New user option 'dictionary-display-definition-function'.
This allows the user to customize the way in which 'dictionary-search'
displays word definitions.  If non-nil, this user option should be set
to a function that displays a word definition obtained from a
dictionary server.  The new function
'dictionary-display-definition-in-help-buffer' can be used to display
the definition in a "*Help*" buffer, instead of the default
"*Dictionary*" buffer.

---
*** New user option 'dictionary-read-word-function'.
This allows the user to customize the way in which 'dictionary-search'
prompts for a word to search in the dictionary.  This user option
should be set to a function that lets the user select a word and
returns it as a string.  The new function
'dictionary-completing-read-word' can be used to prompt with
completion based on dictionary matches.

---
*** New user option 'dictionary-read-dictionary-function'.
This allows the user to customize the way in which 'dictionary-search'
prompts for a dictionary to search in.  This user option should be set
to a function that lets the user select a dictionary and returns its
name as a string.  The new function
'dictionary-completing-read-dictionary' can be used to prompt with
completion based on dictionaries that the server supports.

** Pp

*** New 'pp-default-function' user option replaces 'pp-use-max-width'.

*** New default pretty printing function, which tries to obey 'fill-column'.

*** 'pp-to-string' takes an additional PP-FUNCTION argument.
This argument specifies the prettifying algorithm to use.

** Emacs Lisp mode

---
*** ',@' now has 'prefix' syntax.
Previously, the '@' character, which normally has 'symbol' syntax,
would combine with a following Lisp symbol and interfere with symbol
searching.

---
*** 'emacs-lisp-docstring-fill-column' now defaults to 72.
It was previously 65.  The new default formats documentation strings to
fit on fewer lines without negatively impacting readability.

** CPerl mode

---
*** Subroutine signatures are now supported.
CPerl mode fontifies subroutine signatures like variable declarations
which makes them visually distinct from subroutine prototypes.

*** Syntax of Perl up to version 5.38 is supported.
CPerl mode supports the new keywords for exception handling and the
object oriented syntax which were added in Perl 5.36 and 5.38.

*** New user option 'cperl-fontify-trailer'.
This user option takes the values 'perl-code' or 'comment' and treats
text after an "__END__" or "__DATA__" token accordingly.  The default
value of 'perl-code' is useful for trailing POD and for AutoSplit
modules, the value 'comment' makes CPerl mode treat trailers as
comment, like Perl mode does.

*** New command 'cperl-file-style'.
This command sets the indentation style for the current buffer.  To
change the default style, either use the user option with the same name
or use the command 'cperl-set-style'.

*** Commands using the Perl info page are obsolete.
The Perl documentation in info format is no longer distributed with
Perl or on CPAN since more than 10 years.  Perl documentation can be
read with 'cperl-perldoc' instead.

*** Highlighting trailing whitespace has been removed.
The user option 'cperl-invalid-face' is now obsolete, and does
nothing.  See the user option 'show-trailing-whitespace' instead.

** Emacs Sessions (Desktop)

+++
*** Restoring buffers visiting remote files can now time out.
When a buffer is restored which visits a remote file, the restoration
of the session could hang if the remote host is off-line or slow to
respond.  Setting the user option 'remote-file-name-access-timeout' to
a positive number will abandon the attempt to restore such buffers
after a timeout of that many seconds, thus allowing the rest of
desktop restoration to continue.

** Recentf

+++
*** Checking recent remote files can now time out.
Similarly to buffer restoration by Desktop, 'recentf-mode' checking
of the accessibility of remote files can now time out if
'remote-file-name-access-timeout' is set to a positive number.

** Notifications

+++
*** Allow using Icon Naming Specification for ':app-icon'.
You can use a symbol as the value for ':app-icon' to provide icon name
without specifying a file, like this:

    (notifications-notify
      :title "I am playing music" :app-icon 'multimedia-player)

** Image

+++
*** Image :map property is now recomputed when image is transformed.
Now images with clickable maps work as expected after you run commands
such as `image-increase-size', `image-decrease-size', `image-rotate',
`image-flip-horizontally', and `image-flip-vertically'.

+++
*** New user option 'image-recompute-map-p'
Set this option to nil to prevent Emacs from recomputing image maps.

** Image Dired

*** New user option 'image-dired-thumb-naming'.
You can now configure how a thumbnail is named using this option.

** ERT

+++
*** New macro 'skip-when' to skip 'ert-deftest' tests.
This can help avoid some awkward skip conditions.  For example
'(skip-unless (not noninteractive))' can be changed to the easier
to read '(skip-when noninteractive)'.

+++
*** Syntax highlighting unit testing support.
An ERT extension ('ert-font-lock') now provides support for face
assignment unit testing.  For more information, see the "(ert) Syntax
Highlighting Tests" node in the ERT manual.

** URL

+++
*** 'url-gateway-broken-resolution' is now obsolete.
This option was intended for use on SunOS 4.x and Ultrix systems,
neither of which have been supported by Emacs since version 23.1.
The user option 'url-gateway-nslookup-program' and the function
'url-gateway-nslookup-host' are consequently also obsolete.

** Socks

+++
*** Socks supports version 4a.
The 'socks-server' user option accepts '4a' as a value for its version
field.

** Edmacro

+++
*** New command 'edmacro-set-macro-to-region-lines'.
Bound to 'C-c C-r', this command replaces the macro text with the
lines of the region.  If needed, the region is extended to include
whole lines.  If the region ends at the beginning of a line, that last
line is excluded.

+++
*** New user option 'edmacro-reverse-macro-lines'.
When this is non-nil, the lines of key sequences are displayed with
the most recent line first.  This is can be useful when working with
macros with many lines, such as from 'kmacro-edit-lossage'.

** Proced

---
*** More control on automatic update of Proced buffers.
The user option 'proced-auto-update-flag' can now be set to 2 additional
values, which control automatic updates of Proced buffers that are not
displayed in some window.

** Miscellaneous

---
*** Webjump now assumes URIs are HTTPS instead of HTTP.
For links in 'webjump-sites' without an explicit URI scheme, it was
previously assumed that they should be prefixed with "http://".  Such
URIs are now prefixed with "https://" instead.

---
*** 'bug-reference-mode' now supports 'thing-at-point'.
Now, calling '(thing-at-point 'url)' when point is on a bug reference
will return the URL for that bug.

+++
*** New user option 'rcirc-log-time-format'
This allows for rcirc logs to use a custom timestamp format, than the
chat buffers use by default.

---
*** New user option 'Buffer-menu-group-by'.
It controls how buffers are divided into groups that are displayed with
headings using Outline minor mode.

+++
*** New command 'Buffer-menu-toggle-internal'.
This command toggles the display of internal buffers in Buffer Menu mode;
that is, buffers not visiting a file and whose names start with a space.
Previously, such buffers were never shown.  This command is bound to 'I'
in Buffer Menu mode.

** Customize

+++
*** New command 'customize-dirlocals'.
This command pops up a buffer to edit the settings in ".dir-locals.el".

---
** New command 'customize-toggle-option'.
This command can toggle boolean options for the duration of a session.

** Calc

+++
*** Calc parses fractions written using U+2044 FRACTION SLASH.
Fractions of the form "123⁄456" are handled as if written "123:456".
Note in particular the difference in behavior from U+2215 DIVISION SLASH
and U+002F SOLIDUS, which result in division rather than a rational
fraction.  You may also be interested to know that precomposed fraction
characters, such as ½ (U+00BD VULGAR FRACTION ONE HALF), are also
recognized as rational fractions.  They have been since 2004, but it
looks like it was never mentioned in the NEWS, or even the manual.

** IELM

---
*** IELM now remembers input history between sessions.
The new user option 'ielm-history-file-name' is the name of the file
where IELM input history will be saved.  Customize it to nil to revert
to the old behavior of not remembering input history between sessions.

** EasyPG

+++
*** New user option 'epa-keys-select-method'.
This allows the user to customize the key selection method, which can be
either by using a pop-up buffer or from the minibuffer.  The pop-up
buffer method is the default, which preserves previous behavior.

** Xwidget Webkit

+++
*** New user option 'xwidget-webkit-disable-javascript'.
This allows disabling JavaScript in xwidget Webkit sessions.

** ls-lisp

---
*** 'ls-lisp--insert-directory' supports more long options of 'ls'.
'ls-lisp--insert-directory', the ls-lisp implementation of
'insert-directory', now supports the '--time=TIME' and '--sort=time'
options of GNU 'ls'.


* New Modes and Packages in Emacs 30.1

** New major modes based on the tree-sitter library

+++
*** New major mode 'html-ts-mode'.
An optional major mode based on the tree-sitter library for editing
HTML files.

---
*** New major mode 'heex-ts-mode'.
A major mode based on the tree-sitter library for editing HEEx files.

---
*** New major mode 'elixir-ts-mode'.
A major mode based on the tree-sitter library for editing Elixir files.

---
*** New major mode 'lua-ts-mode'.
A major mode based on the tree-sitter library for editing Lua files.

** Minibuffer and Completions

+++
*** New global minor mode 'minibuffer-regexp-mode'.
This is a minor mode for editing regular expressions in the minibuffer.
It highlights parens via ‘show-paren-mode’ and ‘blink-matching-paren’ in
a user-friendly way, avoids reporting alleged paren mismatches and makes
sexp navigation more intuitive.

+++
*** New minor mode 'completion-preview-mode'.
This minor mode shows you symbol completion suggestions as you type,
using an inline preview.  New user options in the 'completion-preview'
customization group control exactly when Emacs displays this preview.
'completion-preview-mode' is buffer-local, to enable it globally use
'global-completion-preview-mode'.

---
** The highly accessible Modus themes collection has eight items.
The 'modus-operandi' and 'modus-vivendi' are the main themes that have
been part of Emacs since version 28.  The former is light, the latter
dark.  In addition to these, we now have 'modus-operandi-tinted' and
'modus-vivendi-tinted' for easier legibility, as well as
'modus-operandi-deuteranopia', 'modus-vivendi-deuteranopia',
'modus-operandi-tritanopia', and 'modus-vivendi-tritanopia' to cover
the needs of users with red-green or blue-yellow color deficiency.
The Info manual "(modus-themes) Top" describes the details and
showcases all their customization options.

+++
** New global minor mode 'etags-regen-mode'.
This minor mode generates the tags table automatically based on the
current project configuration, and later updates it as you edit the
files and save the changes.

+++
** New package Compat.
Emacs now comes with a stub implementation of the
forwards-compatibility Compat package from GNU ELPA.  This allows
built-in packages to use the library more effectively, and helps
preventing the installation of Compat if unnecessary.

+++
** New package PEG.
Emacs now includes a library for writing Parsing Expression
Grammars (PEG), an approach to text parsing that provides more structure
than regular expressions, but less complexity than context-free
grammars.  The Info manual "(elisp) Parsing Expression Grammars" has
documentation and examples.


* Incompatible Lisp Changes in Emacs 30.1

---
** Old derived.el functions removed.
The following functions have been deleted because they were only used
by code compiled with Emacs<21:
'derived-mode-init-mode-variables', 'derived-mode-merge-abbrev-tables',
'derived-mode-merge-keymaps', 'derived-mode-merge-syntax-tables',
'derived-mode-run-hooks', 'derived-mode-set-abbrev-table',
'derived-mode-set-keymap', 'derived-mode-set-syntax-table',
'derived-mode-setup-function-name'.

+++
** 'M-TAB' now invokes 'completion-at-point' also in Text mode.
By default, Text mode no longer binds 'M-TAB' to
'ispell-complete-word'.  Instead, this mode arranges for
'completion-at-point', globally bound to 'M-TAB', to perform word
completion as well.  You can have Text mode bind 'M-TAB' to
'ispell-complete-word' as it did in previous Emacs versions, or
disable Ispell word completion in Text mode altogether, by customizing
the new user option 'text-mode-ispell-word-completion'.

** 'pp' and 'pp-to-string' now always include a terminating newline.
In the past they included a terminating newline in most cases but not all.

** 'buffer-match-p' and 'match-buffers' take '&rest args'.
They used to take a single '&optional arg' and were documented to use
an unreliable hack to try and support condition predicates that
don't accept this optional arg.
The new semantics makes no such accommodation, but the code still
supports it (with a warning) for backward compatibility.

** 'post-gc-hook' runs after updating 'gcs-done' and 'gcs-elapsed'.

---
** The escape sequence '\x' not followed by hex digits is now an error.
Previously, '\x' without at least one hex digit denoted character code
zero (NUL) but as this was neither intended nor documented or even
known by anyone, it is now treated as an error by the Lisp reader.

---
** Connection-local variables are applied in buffers visiting a remote file.
This overrides possible directory-local or file-local variables with
the same name.

---
** User option 'tramp-completion-reread-directory-timeout' has been removed.
This user option has been obsoleted in Emacs 27, use
'remote-file-name-inhibit-cache' instead.

---
** User options 'eshell-NAME-unload-hook' are now obsolete.
These hooks were named incorrectly, and so they never actually ran
when unloading the corresponding feature.  Instead, you should use
hooks named after the feature name, like 'esh-mode-unload-hook'.

+++
** 'copy-tree' now copies records when its optional 2nd argument is non-nil.

+++
** Regexp zero-width assertions followed by operators are better defined.
Previously, regexps such as "xy\\B*" would have ill-defined behavior.
Now any operator following a zero-width assertion applies to that
assertion only (which is useless).  For historical compatibility, an
operator character following '^' or '\`' becomes literal, but we
advise against relying on this.

---
** Mode-line mnemonics for some coding-systems have changed.
The mode-line mnemonic for 'utf-7' is now the lowercase 'u', to be
consistent with the other encodings of this family.

The mode-line mnemonic for 'koi8-u' is now 'У', U+0423 CYRILLIC
CAPITAL LETTER U, to distinguish between this encoding and the
UTF-8/UTF-16 family.

If your terminal cannot display 'У', or if you want to get the old
behavior back for any other reason, you can do that using the
'coding-system-put' function.  For example, the following restores the
previous behavior of showing 'U' in the mode line for 'koi8-u':

    (coding-system-put 'koi8-u :mnemonic ?U)

---
** 'vietnamese-tcvn' is now a coding system alias for 'vietnamese-vscii'.
VSCII-1 and TCVN-5712 are different names for the same character
encoding.  Therefore, the duplicate coding system definition has been
dropped in favor of an alias.

The mode-line mnemonic for 'vietnamese-vscii' and its aliases is the
lowercase letter 'v'.

+++
** Infinities and NaNs no longer act as symbols on non-IEEE platforms.
On old platforms like the VAX that do not support IEEE floating-point,
tokens like 0.0e+NaN and 1.0e+INF are no longer read as symbols.
Instead, the Lisp reader approximates an infinity with the nearest
finite value, and a NaN with some other non-numeric object that
provokes an error if used numerically.

+++
** X color support compatibility aliases are now marked obsolete.
The compatibility aliases 'x-defined-colors', 'x-color-defined-p',
'x-color-values', and 'x-display-color-p' are now obsolete.

+++
** 'easy-mmode-define-{minor,global}-mode' aliases are now obsolete.
Use 'define-minor-mode' and 'define-globalized-minor-mode' instead.

** The obsolete calling convention of 'sit-for' has been removed.
That convention was: '(sit-for SECONDS MILLISEC &optional NODISP)'.

** The 'millisec' argument of 'sleep-for' has been declared obsolete.
Use a float value for the first argument instead.

** 'eshell-process-wait-{seconds,milliseconds}' options are now obsolete.
Instead, use 'eshell-process-wait-time', which supports floating-point
values.

** JSON

---
*** The parser keeps duplicated object keys in alist and plist output.
A JSON object such as '{"a":1,"a":2}' will now be translated into the
Lisp values '((a . 1) (a . 2))' or '(:a 1 :a 2)' if alist or plist
object types are requested.

---
*** The parser sometimes signals different types of errors.
It will now signal 'json-utf8-decode-error' for inputs that are not
correctly UTF-8 encoded.


* Lisp Changes in Emacs 30.1

** New function 'help-fns-function-name'.
For named functions, it just returns the name and otherwise
it returns a short "unique" string that identifies the function.
In either case, the string is propertized so clicking on it gives
further details.

** New function 'cl-type-of'.
This function is like 'type-of' except that it sometimes returns
a more precise type.  For example, for nil and t it returns 'null'
and 'boolean' respectively, instead of just 'symbol'.

** New functions `primitive-function-p` and `cl-functionp`.
`primitive-function-p` is like `subr-primitive-p` except that it returns
t only if the argument is a function rather than a special-form,
and `cl-functionp` is like `functionp` except it return nil
for lists and symbols.

** Built-in types have now corresponding classes.
At the Lisp level, this means that things like (cl-find-class 'integer)
will now return a class object, and at the UI level it means that
things like 'C-h o integer RET' will show some information about that type.

** New var 'major-mode-remap-defaults' and function 'major-mode-remap'.
The first is like Emacs-29's 'major-mode-remap-alist' but to be set by
packages (instead of users).  The second looks up those two variables.

+++
** Pcase's functions (in 'pred' and 'app') can specify the argument position.
For example, instead of '(pred (< 5))' you can write '(pred (> _ 5))'.

+++
** 'define-advice' now sets the new advice's 'name' property to NAME.
Named advices defined with 'define-advice' can now be removed with
'(advice-remove SYMBOL NAME)' in addition to '(advice-remove SYMBOL
SYMBOL@NAME)'.

+++
** New function 'require-with-check' to detect new versions shadowing.
This is like 'require', but it checks whether the argument 'feature'
is already loaded, in which case it either signals an error or
forcibly reloads the file that defines the feature.

+++
** New variable 'lisp-eval-depth-reserve'.
It puts a limit to the amount by which Emacs can temporarily increase
'max-lisp-eval-depth' when handling signals.

+++
** New special form 'handler-bind'.
It provides a functionality similar to 'condition-case' except it runs
the handler code without unwinding the stack, such that we can record
the backtrace and other dynamic state at the point of the error.  See
the Info node "(elisp) Handling Errors".

+++
** New 'pop-up-frames' action alist entry for 'display-buffer'.
This has the same effect as the variable of the same name and takes
precedence over the variable when present.

** New function 'merge-ordered-lists'.
Mostly used internally to do a kind of topological sort of
inheritance hierarchies.

+++
** New polymorphic comparison function 'value<'.
This function returns non-nil if the first argument is less than the
second.  It works for any two values of the same type with reasonable
ordering for numbers, strings, symbols, bool-vectors, markers, buffers
and processes.  Conses, lists, vectors and records are ordered
lexicographically.
It is intended as a convenient ordering predicate for sorting, and is
likely to be faster than hand-written Lisp functions.

+++
** New 'sort' arguments and features.
The 'sort' function can now be called using the signature

    (sort SEQ &rest KEYWORD-ARGUMENTS)

where arguments after the first are keyword/value pairs, all optional:
':key' specifies a function that produces the sorting key from an element,
':lessp' specifies the ordering predicate, defaulting to 'value<',
':reverse' is used to reverse the sorting order,
':in-place is used for in-place sorting, as the default is now to
sort a copy of the input.

The new signature is less error-prone and reduces the need to write
ordering predicates by hand.  We recommend that you use the ':key'
argument instead of ':lessp' unless a suitable ordering predicate is
already available.  This can also be used for multi-key sorting:

    (sort seq :key (lambda (x) (list (age x) (size x) (cost x))))

sorts by the return value of 'age', then by 'size', then by 'cost'.

The old signature, '(sort SEQ PREDICATE)', can still be used and sorts
its input in-place as before.

** New API for 'derived-mode-p' and control of the graph of major modes.

*** 'derived-mode-p' now takes the list of modes as a single argument.
The same holds for 'provided-mode-derived-p'.
The old calling convention where multiple modes are passed as
separate arguments is deprecated.

*** New functions to access the graph of major modes.
While 'define-derived-mode' still only supports single inheritance,
modes can declare additional parents (for tests like 'derived-mode-p')
with 'derived-mode-add-parents'.
Accessing the 'derived-mode-parent' property directly is now
deprecated in favor of the new functions 'derived-mode-set-parent'
and 'derived-mode-all-parents'.

+++
** Drag-and-drop functions can now be called once for compound drops.
It is now possible for drag-and-drop handler functions to respond to
drops incorporating more than one URL.  Functions capable of this must
set their 'dnd-multiple-handler' symbol properties to a non-nil value.
See the Info node "(elisp) Drag and Drop".

Incident to this change, the function 'dnd-handle-one-url' has been
made obsolete, for it cannot take these new handlers into account.

** New function 're-disassemble' to see the innards of a regexp.
If you compiled with '--enable-checking', you can use this to help debug
either your regexp performance problems or the regexp engine.

+++
** XLFDs are no longer restricted to 255 characters.
'font-xlfd-name' now returns an XLFD even if it is greater than 255
characters in length, provided that the LONG_XLFDs argument is true.

Other features in Emacs which employ XLFDs have been modified to
produce and understand XLFDs larger than 255 characters.

** 'defadvice' is marked as obsolete.
See the "(elisp) Porting Old Advice" Info node for help converting
them to use 'advice-add' or 'define-advice' instead.

** 'cl-old-struct-compat-mode' is marked as obsolete.
You may need to recompile our code if it was compiled with Emacs < 24.3.

+++
** New macro 'static-if' for conditional evaluation of code.
This macro hides a form from the evaluator or byte-compiler based on a
compile-time condition.  This is handy for avoiding byte-compilation
warnings about code that will never actually run under some
conditions.

+++
** Desktop notifications are now supported on the Haiku operating system.
The new function 'haiku-notifications-notify' provides a subset of the
capabilities of the 'notifications-notify' function in a manner
analogous to 'w32-notification-notify'.

** New variable 'haiku-pass-control-tab-to-system'.
This sets whether Emacs should pass C-TAB on to the system instead of
handling it, fixing a problem where window switching would not activate
if an Emacs frame had focus on the Haiku operation system.

+++
** New value 'if-regular' for the REPLACE argument to 'insert-file-contents'.
It results in 'insert-file-contents' erasing the buffer instead of
preserving markers if the file being inserted is not a regular file,
rather than signaling an error.

+++
** New variable 'current-key-remap-sequence'.
It is bound to the key sequence that caused a call to a function bound
within 'function-key-map' or 'input-decode-map' around those calls.

+++
** New variables describing the names of built in programs.
The new variables 'ctags-program-name', 'ebrowse-program-name',
'etags-program-name', 'hexl-program-name', 'emacsclient-program-name'
'movemail-program-name', and 'rcs2log-program-name' should be used
instead of "ctags", "ebrowse", "etags", "hexl", "emacsclient", and
"rcs2log", when starting one of these built in programs in a
subprocess.

+++
** New variable 'case-symbols-as-words' affects case operations for symbols.
If non-nil, then case operations such as 'upcase-initials' or
'replace-match' (with nil FIXEDCASE) will treat the entire symbol name
as a single word.  This is useful for programming languages and styles
where only the first letter of a symbol's name is ever capitalized.
The default value of this variable is nil.

+++
** 'x-popup-menu' now understands touch screen events.
When a 'touchscreen-begin' or 'touchscreen-end' event is passed as the
POSITION argument, it will behave as if that event was a mouse event.

+++
** New functions for handling touch screen events.
The new functions 'touch-screen-track-tap' and
'touch-screen-track-drag' handle tracking common touch screen gestures
from within a command.

** New user option 'safe-local-variable-directories'.
This user option names directories in which Emacs will treat all
directory-local variables as safe.

+++
** New parameter to 'touchscreen-end' events.
CANCEL non-nil establishes that the touch sequence has been
intercepted by programs such as window managers and should be ignored
with Emacs.

** New variable 'inhibit-auto-fill' to temporarily prevent auto-fill.

+++
** New variable 'secondary-tool-bar-map'.
If non-nil, this variable contains a keymap of menu items that are
displayed along tool bar items inside 'tool-bar-map'.

** New variable 'completion-lazy-hilit'.
Lisp programs that present completion candidates may bind this
variable non-nil around calls to functions such as
'completion-all-completions'.  This tells the underlying completion
styles to skip eager fontification of completion candidates, which
improves performance.  Such a Lisp program can then use the
'completion-lazy-hilit' function to fontify candidates just in time.

** New primitive 'buffer-last-name'.
It returns the name of a buffer before the last time it was renamed or
killed.

** New primitive 'marker-last-position'.
It returns the last position of a marker in its buffer even if that
buffer has been killed.  ('marker-position' would return nil in that
case.)


** Functions and variables to transpose sexps

+++
*** New helper variable 'transpose-sexps-function'.
Emacs now can set this variable to customize the behavior of the
'transpose-sexps' function.

+++
*** New function 'transpose-sexps-default-function'.
The previous implementation is moved into its own function, to be
bound by 'transpose-sexps-function'.

*** New function 'treesit-transpose-sexps'.
Tree-sitter now unconditionally sets 'transpose-sexps-function' for all
tree-sitter enabled modes.  This functionality utilizes the new
'transpose-sexps-function'.

** Functions and variables to move by program statements

*** New variable 'forward-sentence-function'.
Major modes can now set this variable to customize the behavior of the
'forward-sentence' command.

*** New function 'forward-sentence-default-function'.
The previous implementation of 'forward-sentence' is moved into its
own function, to be bound by 'forward-sentence-function'.

*** New function 'treesit-forward-sentence'.
All tree-sitter enabled modes that define 'sentence' in
'treesit-thing-settings' now set 'forward-sentence-function' to call
'treesit-forward-sentence'.

** Functions and variables to move by program sexps

*** New function 'treesit-forward-sexp'.
Tree-sitter conditionally sets 'forward-sexp-function' for major modes
that have defined 'sexp' in 'treesit-thing-settings' to enable
sexp-related motion commands.

+++
** Returned strings are never docstrings.
Functions and macros whose bodies consist of a single string literal now
only return that string; it is not used as a docstring.  Example:

    (defun sing-a-song ()
      "Sing a song.")

The above function returns the string '"Sing a song."' but has no
docstring.  Previously, that string was used as both a docstring and
return value, which was never what the programmer wanted.  If you want
the string to be a docstring, add an explicit return value.

This change applies to 'defun', 'defsubst', 'defmacro' and 'lambda'
forms; other defining forms such as 'cl-defun' already worked this way.

** New or changed byte-compilation warnings

---
*** Warn about missing 'lexical-binding' directive.
The compiler now warns if an Elisp file lacks the standard
'-*- lexical-binding: ... -*-' cookie on the first line.
This line typically looks something like

    ;;; My little pony mode  -*- lexical-binding: t -*-

It is needed to inform the compiler about which dialect of ELisp
your code is using: the modern dialect with lexical binding or
the old dialect with only dynamic binding.

Lexical binding avoids some name conflicts and allows the compiler to
detect more mistakes and generate more efficient code, so it is
recommended.  For how to adapt your code to lexical binding, see the
manual section "(elisp) Converting to Lexical Binding".

If your code cannot be converted to lexical binding, you can insert
the line

    ;;; -*- lexical-binding: nil -*-

first in the file to declare that it uses the old dialect.

---
*** Warn about empty bodies for more special forms and macros.
The compiler now warns about an empty body argument to 'when',
'unless', 'ignore-error' and 'with-suppressed-warnings' in addition to
the existing warnings for 'let' and 'let*'.  Example:

    (when (> x 2))

This warning can be suppressed using 'with-suppressed-warnings' with
the warning name 'empty-body'.

---
*** Warn about quoted error names in 'condition-case' and 'ignore-error'.
The compiler now warns about quoted condition (error) names
in 'condition-case' and 'ignore-error'.  Example:

    (condition-case nil
        (/ x y)
      ('arith-error "division by zero"))

Quoting them adds the error name 'quote' to those handled or ignored
respectively, which was probably not intended.

---
*** Warn about comparison with literal constants without defined identity.
The compiler now warns about comparisons by identity with a literal
string, cons, vector, record, function, large integer or float as this
may not match any value at all.  Example:

    (eq x "hello")

Only literals for symbols and small integers (fixnums), including
characters, are guaranteed to have a consistent (unique) identity.
This warning applies to 'eq', 'eql', 'memq', 'memql', 'assq', 'rassq',
'remq' and 'delq'.

To compare by (structural) value, use 'equal', 'member', 'assoc',
'rassoc', 'remove' or 'delete' instead.  Floats and bignums can also
be compared using 'eql', '=' and 'memql'.  Function literals cannot be
compared reliably at all.

This warning can be suppressed using 'with-suppressed-warnings' with
the warning name 'suspicious'.

---
*** Warn about 'condition-case' without handlers.
The compiler now warns when the 'condition-case' form is used without
any actual handlers, as in

    (condition-case nil (read buffer))

because it has no effect other than the execution of the body form.
In particular, no errors are caught or suppressed.  If the intention
was to catch all errors, add an explicit handler for 'error', or use
'ignore-error' or 'ignore-errors'.

This warning can be suppressed using 'with-suppressed-warnings' with
the warning name 'suspicious'.

---
*** Warn about 'unwind-protect' without unwind forms.
The compiler now warns when the 'unwind-protect' form is used without
any unwind forms, as in

    (unwind-protect (read buffer))

because the behavior is identical to that of the argument; there is
no protection of any kind.  Perhaps the intended unwind forms have
been misplaced or forgotten, or the use of 'unwind-protect' could be
simplified away.

This warning can be suppressed using 'with-suppressed-warnings' with
the warning name 'suspicious'.

---
*** Warn about useless trailing 'cond' clauses.
The compiler now warns when a 'cond' form contains clauses following a
default (unconditional) clause.  Example:

    (cond ((= x 0) (say "none"))
          (t (say "some"))
          (say "goodbye"))

Such a clause will never be executed but is likely to be a mistake,
perhaps due to misplaced brackets.

This warning can be suppressed using 'with-suppressed-warnings' with
the warning name 'suspicious'.

---
*** Warn about mutation of constant values.
The compiler now warns about code that modifies program constants in
some obvious cases.  Examples:

    (setcar '(1 2) 7)
    (aset [3 4] 0 8)
    (aset "abc" 1 ?d)

Such code may have unpredictable behavior because the constants are
part of the program, not data structures generated afresh during
execution, and the compiler does not expect them to change.

To avoid the warning, operate on an object created by the program
(maybe a copy of the constant), or use a non-destructive operation
instead.

This warning can be suppressed using 'with-suppressed-warnings' with
the warning name 'mutate-constant'.

---
*** Warn about more ignored function return values.
The compiler now warns when the return value from certain functions is
implicitly ignored.  Example:

    (progn (nreverse my-list) my-list)

will elicit a warning because it is usually pointless to call
'nreverse' on a list without using the returned value.

To silence the warning, make use of the value in some way, such as
assigning it to a variable.  You can also wrap the function call in
'(ignore ...)', or use 'with-suppressed-warnings' with the warning
name 'ignored-return-value'.

The warning will only be issued for calls to functions declared
'important-return-value' or 'side-effect-free' (but not 'error-free').

---
*** Warn about docstrings that contain control characters.
The compiler now warns about docstrings with control characters other
than newline and tab.  This is often a result of improper escaping.
Example:

    (defun my-fun ()
      "Uses c:\remote\dir\files and the key \C-x."
      ...)

where the docstring contains the four control characters 'CR', 'DEL',
'FF' and 'C-x'.

The warning name is 'docstrings-control-chars'.

---
*** The warning about wide docstrings can now be disabled separately.
Its warning name is 'docstrings-wide'.

---
** New user option 'native-comp-async-warnings-errors-kind'.
It allows control of what kinds of warnings and errors from asynchronous
native compilation are reported to the parent Emacs process.  The
default is to report all errors and only important warnings.  If you
were used to customizing 'native-comp-async-report-warnings-errors' to
nil or 'silent', we suggest that you now leave it at its default value,
and see if you get only warnings that matter.

+++
** New function declaration and property 'important-return-value'.
The declaration '(important-return-value t)' sets the
'important-return-value' property which indicates that the function
return value should probably not be thrown away implicitly.

** Bytecode is now always loaded eagerly.
Bytecode compiled with older Emacs versions for lazy loading using
'byte-compile-dynamic' is now loaded all at once.
As a consequence, 'fetch-bytecode' has no use, does nothing, and is
now obsolete.  The variable 'byte-compile-dynamic' has no effect any
more; compilation will always yield bytecode for eager loading.

+++
** New functions 'file-user-uid' and 'file-group-gid'.
These functions are like 'user-uid' and 'group-gid', respectively, but
are aware of file name handlers, so they will return the remote UID or
GID for remote files (or -1 if the connection has no associated user).

+++
** 'fset', 'defalias' and 'defvaralias' now signal an error for cyclic aliases.
Previously, 'fset', 'defalias' and 'defvaralias' could be made to
build circular function and variable indirection chains as in

    (defalias 'able 'baker)
    (defalias 'baker 'able)

but trying to use them would sometimes make Emacs hang.  Now, an attempt
to create such a loop results in an error.

Since circular alias chains now cannot occur, 'function-alias-p',
'indirect-function' and 'indirect-variable' will never signal an error.
Their 'noerror' arguments have no effect and are therefore obsolete.

+++
** 'treesit-font-lock-rules' now accepts additional global keywords.
When supplied with ':default-language LANGUAGE', rules after it will
default to use 'LANGUAGE'.

---
** New optional argument to 'modify-dir-local-variable'.
A 5th argument, optional, has been added to
'modify-dir-local-variable'.  It can be used to specify which
dir-locals file to modify.

** Connection local variables

+++
*** New macros 'connection-local-p' and 'connection-local-value'.
The former macro returns non-nil if a variable has a connection-local
binding.  The latter macro returns the connection-local value of a
variable if any, or its current value.

** Hash tables

+++
*** ':rehash-size' and ':rehash-threshold' args no longer have any effect.
These keyword arguments are now ignored by 'make-hash-table'.  Emacs
manages the memory for all hash table objects in the same way.
The functions 'hash-table-rehash-size' and 'hash-table-rehash-threshold'
remain for compatibility but now always return the old default values.

+++
*** The printed representation has been shrunk and simplified.
The 'test' parameter is omitted if it is 'eql' (the default), as is
'data' if empty.  'rehash-size', 'rehash-threshold' and 'size' are
always omitted, and ignored if present when the object is read back in.

** Obarrays

+++
*** New obarray type.
Obarrays are now represented by an opaque type instead of using vectors.
They are created by 'obarray-make' and manage their internal storage
automatically, which means that the size parameter to 'obarray-make' can
safely be omitted.  That is, they do not become slower as they fill up.

The old vector representation is still accepted by functions operating
on obarrays, but 'obarrayp' only returns t for obarray objects.
'type-of' now returns 'obarray' for obarray objects.

Old code which (incorrectly) created "obarrays" as Lisp vectors filled
with something other than 0, as in '(make-vector N nil)', will no longer
work, and should be rewritten to use 'obarray-make'.  Alternatively, you
can fill the vector with 0.

+++
*** New function 'obarray-clear' removes all symbols from an obarray.

---
*** 'obarray-size' and 'obarray-default-size' are now obsolete.
They pertained to the internal storage size which is now irrelevant.

+++
** 'treesit-install-language-grammar' can handle local directory instead of URL.
It is now possible to pass a directory of a local repository as URL
inside 'treesit-language-source-alist', so that calling
'treesit-install-language-grammar' would avoid cloning the repository.
It may be useful, for example, for the purposes of bisecting a
treesitter grammar.

+++
** New buffer-local variable 'tabulated-list-groups'.
It controls display and separate sorting of groups of entries.

---
** New text property 'context-menu-functions'.
Like the variable with the same name, it adds menus from the list that
is the value of the property to context menus shown when clicking on the
text which as this property.

---
** Detecting the end of an iteration of a keyboard macro
'read-event', 'read-char', and 'read-char-exclusive' no longer return -1
when called at the end of an iteration of a the execution of a keyboard
macro.  Instead, they will transparently continue reading available input
(e.g., from the keyboard).  If you need to detect the end of a macro
iteration, check the following condition before calling one of the
aforementioned functions:

    (and (arrayp executing-kbd-macro)
         (>= executing-kbd-macro-index (length executing-kbd-macro))))

+++
** 'vtable-update-object' updates an existing object with just two arguments.
It is now possible to update the representation of an object in a vtable
by calling 'vtable-update-object' with just the vtable and the object as
arguments.  (Previously the 'old-object' argument was required which, in
this case, would mean repeating the object in the argument list.)  When
replacing an object with a different one, passing both the new and old
objects is still necessary.

---
** The JSON encoder and decoder now accept arbitarily large integers.
Previously, they were limited to the range of signed 64-bit integers.

** New tree-sitter functions and variables for defining and using "things"

+++
*** New variable 'treesit-thing-settings'.

New variable that allows users to define "things" like 'defun', 'text',
'sexp', for navigation commands and tree-traversal functions.

+++
*** New navigation functions 'treesit-thing-prev', 'treesit-thing-next', 'treesit-navigate-thing', 'treesit-beginning-of-thing', 'treesit-end-of-thing'.

+++
*** New functions 'treesit-thing-at', 'treesit-thing-at-point'.

+++
*** Tree-tarversing functions 'treesit-search-subtree', 'treesit-search-forward', 'treesit-search-forward-goto', 'treesit-induce-sparse-tree' now accepts more kinds of predicates.

Now users can use thing symbols (defined in 'treesit-thing-settings'),
and any thing definitions for the predicate argument.

** Other tree-sitter function and variable changes

+++
*** 'treesit-parser-list' now takes additional optional arguments, LANGUAGE and TAG.

If LANGUAGE is given, only return parsers for that language.  If TAG is
given, only return parsers with that tag.  Note that passing nil as tag
doesn't mean return all parsers, but rather "all parsers with no tags".


* Changes in Emacs 30.1 on Non-Free Operating Systems

** MS-Windows

+++
*** You can now opt out of following the system's Dark mode.
By default, Emacs on MS-Windows follows the system's Dark mode for its
title bars' and scroll bars' appearance.  If the new user option
'w32-follow-system-dark-mode' is customized to the nil value, Emacs
will disregard the system's Dark mode and will always use the default
Light mode.


----------------------------------------------------------------------
This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.


Local variables:
coding: utf-8
mode: outline
mode: emacs-news
paragraph-separate: "[	 ]"
end: