Re: scratch/igc cedb01b6c9c: ; * README-IGC: Fix typos and wording.

Re: scratch/igc cedb01b6c9c: ; * README-IGC: Fix typos and wording.

[Pip Cet via Emacs development discussions.]

"Eli Zaretskii" <eliz@gnu.org> writes:

> branch: scratch/igc
> commit cedb01b6c9c68051e00426415e21a960fdc3de76
> Author: Eli Zaretskii <eliz@gnu.org>
> Commit: Eli Zaretskii <eliz@gnu.org>
>
>     ; * README-IGC: Fix typos and wording.

Thanks!

> -It's recommended to use the .gdbinit file in the src/ subdirectory,
> -which configures gdb not to stop in this situation.
> +part of its normal operation.  When running Emacs with MPS support in a
> +debugger such as GDB, it is important to take this into account, because
> +the debugger might stop when this signal is raised, and make it look
> +like Emacs segfaulted.

Can we lose that last half-sentence?  Emacs did segfault, it's just that
the segfault was expected, so this will only cause confusion.

> +If you use GDB, it's recommended to use the .gdbinit file in the src/
> +subdirectory, which configures GDB not to stop in this situation.
> +Starting GDB from the src directory will cause it automatically load and
> +read the file, subject to the "auto-load safe-path" setting;
> +alternatively, you can force GDB to read that file manually, after
> +starting the debugger:
> +
> +  (gdb) source /path/to/emacs-igc/src/.gdbinit

Can we shorten this to just

> +If you use GDB, it's recommended to use the .gdbinit file in the src/
> +subdirectory:
> +
> +  (gdb) source /path/to/emacs-igc/src/.gdbinit

? I think those few people who use gdb distributions which allow
auto-loading .gdbinit files will know they can skip this step (and if
they don't, no harm done). The text you pushed makes it sound like we're
advising people to change the auto-load safe-path setting to include the
current directory, and we definitely don't want to do that.

(I intentionally omitted the "If you use GDB" part: we don't want people
to use lldb on GNU/Linux systems, which will result in less useful bug
reports)

Pip

Re: scratch/igc cedb01b6c9c: ; * README-IGC: Fix typos and wording.

[Eli Zaretskii]

> Date: Fri, 13 Dec 2024 12:42:03 +0000
> From: Pip Cet <pipcet@protonmail.com>
> Cc: Eli Zaretskii <eliz@gnu.org>
> 
> > -It's recommended to use the .gdbinit file in the src/ subdirectory,
> > -which configures gdb not to stop in this situation.
> > +part of its normal operation.  When running Emacs with MPS support in a
> > +debugger such as GDB, it is important to take this into account, because
> > +the debugger might stop when this signal is raised, and make it look
> > +like Emacs segfaulted.
> 
> Can we lose that last half-sentence?  Emacs did segfault, it's just that
> the segfault was expected, so this will only cause confusion.

I wanted to distinguish between a real crash and SIGSEGV that is part
of "normal" MPS operation.  Feel free to suggest a different wording,
but the distinction is important to mention, because otherwise it is
not clear why this is at all an issue.

> > +If you use GDB, it's recommended to use the .gdbinit file in the src/
> > +subdirectory, which configures GDB not to stop in this situation.
> > +Starting GDB from the src directory will cause it automatically load and
> > +read the file, subject to the "auto-load safe-path" setting;
> > +alternatively, you can force GDB to read that file manually, after
> > +starting the debugger:
> > +
> > +  (gdb) source /path/to/emacs-igc/src/.gdbinit
> 
> Can we shorten this to just
> 
> > +If you use GDB, it's recommended to use the .gdbinit file in the src/
> > +subdirectory:
> > +
> > +  (gdb) source /path/to/emacs-igc/src/.gdbinit
> 
> ? I think those few people who use gdb distributions which allow
> auto-loading .gdbinit files will know they can skip this step (and if
> they don't, no harm done). The text you pushed makes it sound like we're
> advising people to change the auto-load safe-path setting to include the
> current directory, and we definitely don't want to do that.

No, we don't advise anything like that.  We just explain why GDB might
say something like

  warning: File "/foo/bar/emacs/branch/src/.gdbinit" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir;$datadir/../auto-load".
  To enable execution of this file add
	  add-auto-load-safe-path /foo/bar/emacs/branch/src/.gdbinit
  line to your configuration file "~/.config/gdb/gdbinit".
  To completely disable this security protection add
	  set auto-load safe-path /
  line to your configuration file "~/.config/gdb/gdbinit".
  For more information about this security protection see the
  "Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
	  info "(gdb)Auto-loading safe path"

We ask people to try the branch, but we don't expect them to be
proficient in using GDB, let alone be GDB experts.  Many people are
very confused when they use GDB, and need every piece of advice we can
provide to feel "at home" with GDB.

> (I intentionally omitted the "If you use GDB" part: we don't want people
> to use lldb on GNU/Linux systems, which will result in less useful bug
> reports)

The information there is specific to GDB, so making it sound like it's
applicable to every debugger will unnecessarily confuse people.  On
macOS, using GDB is not easy, to say the least, and we do want people
to test the branch on that platform as well.