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

Copyright (C) 2022-2023 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'.

Temporary note:
+++ indicates that all relevant manuals in doc/ have been updated.
--- means no change in the manuals is needed.
When you add a new item, use the appropriate mark if you are sure it
applies, and please also update docstrings as needed.

\f
* Installation Changes in Emacs 30.1

---
** 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.

\f
* Startup Changes in Emacs 30.1

\f
* Changes in Emacs 30.1

** 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' in non-nil.

** 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.

+++
** '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 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'.

** 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'.

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

** 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'.

\f
* Editing Changes in Emacs 30.1

---
** 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.

\f
* Changes in Specialized Modes and Packages in Emacs 30.1

---
** 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)))

** 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.

** VC

---
*** 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.

** Diff Mode

+++
*** '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".

** 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 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.

+++
*** 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)

---
*** 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.

** 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.

** 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 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 to
access 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 allows to kill only selected remote buffers, controlled by 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.

** 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.

** 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, call the 'man' program synchronously rather than
asynchronously (which is the default behavior).

** 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.

** 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-side-effects'.
When non-nil, package specifications with side-effects for building
software will be used when building a package.

** 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.

** 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'.

** use-package

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

** 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 to, respectively, post to,
unsubscribe from, request help about, and browse 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.

** 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.

** 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.

** Image Dired

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

\f
* 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.

---
** 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.

\f
* Incompatible Lisp Changes in Emacs 30.1

---
** 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 correspending 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)

+++
** 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.

\f
* Lisp Changes in Emacs 30.1

+++
** 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.

** 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 buffer-local variable 'treesit-sentence-type-regexp'.
Similarly to 'treesit-defun-type-regexp', this variable is used to
define "sentences" in tree-sitter enabled modes.

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

** Functions and variables to move by program sexps

*** New buffer-local variable 'treesit-sexp-type-regexp'.
Similarly to 'treesit-defun-type-regexp', this variable is used to
define "sexps" in tree-sitter enabled modes.

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

** New or changed byte-compilation warnings

---
*** 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 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').

+++
** 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.

+++
** 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.

\f
* Changes in Emacs 30.1 on Non-Free Operating Systems

\f
----------------------------------------------------------------------
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/>.

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