[Bug cli/29800] New: Trying to "document" an undefined command causes crash

[Bug cli/29800] New: Trying to "document" an undefined command causes crash

[hp at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

            Bug ID: 29800
           Summary: Trying to "document" an undefined command causes crash
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: cli
          Assignee: unassigned at sourceware dot org
          Reporter: hp at sourceware dot org
  Target Milestone: ---

Trying to "document" an undefined (not "define"d yet), causes gdb to crash.
This is a build from  git://sourceware.org/git/binutils-gdb.git at
cbda14deaf49.
(All directory names below are manually redacted and may contain typos.)

I checked out gdb-binutils tree, configured with "--prefix /tmp/foo" and built
and installed with "make all" and "make install".

Then, executing /tmp/foo/bin/gdb and just writing "document foo" gets me:

(gdb) document foo


Fatal signal: Segmentation fault
----- Backtrace -----
0x55a2f1388169 gdb_internal_backtrace_1
        /path/to/checkout/binutils-gdb-git/gdb/bt-utils.c:122
0x55a2f1388169 _Z22gdb_internal_backtracev
        /path/to/checkout/binutils-gdb-git/gdb/bt-utils.c:168
0x55a2f149fa6f handle_fatal_signal
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:964
0x55a2f149fbde handle_sigsegv
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:1037
0x7ff51c00013f ???
        ./nptl/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0x55a2f13cc14e do_document_command
        /path/to/checkout/binutils-gdb-git/gdb/cli/cli-script.c:1519
0x55a2f13bbb34 _Z8cmd_funcP16cmd_list_elementPKci
        /path/to/checkout/binutils-gdb-git/gdb/cli/cli-decode.c:2543
0x55a2f16c2331 _Z15execute_commandPKci
        /path/to/checkout/binutils-gdb-git/gdb/top.c:692
0x55a2f14a081c _Z15command_handlerPKc
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:616
0x55a2f14a0bac
_Z20command_line_handlerOSt10unique_ptrIcN3gdb13xfree_deleterIcEEE
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:860
0x55a2f14a11c0 gdb_rl_callback_handler
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:246
0x55a2f176d83f rl_callback_read_char
        /path/to/checkout/binutils-gdb-git/readline/readline/callback.c:290
0x55a2f149fc2d gdb_rl_callback_read_char_wrapper_noexcept
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:188
0x55a2f14a10a0 gdb_rl_callback_read_char_wrapper
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:221
0x55a2f149f93f stdin_event_handler
        /path/to/checkout/binutils-gdb-git/gdb/event-top.c:541
0x55a2f186fb25 gdb_wait_for_event
        /path/to/checkout/binutils-gdb-git/gdbsupport/event-loop.cc:694
0x55a2f1870353 gdb_wait_for_event
        /path/to/checkout/binutils-gdb-git/gdbsupport/event-loop.cc:593
0x55a2f1870353 _Z16gdb_do_one_eventi
        /path/to/checkout/binutils-gdb-git/gdbsupport/event-loop.cc:264
0x55a2f1575a79 start_event_loop
        /path/to/checkout/binutils-gdb-git/gdb/main.c:411
0x55a2f1575a79 captured_command_loop
        /path/to/checkout/binutils-gdb-git/gdb/main.c:471
0x55a2f1577564 captured_main
        /path/to/checkout/binutils-gdb-git/gdb/main.c:1330
0x55a2f1577564 _Z8gdb_mainP18captured_main_args
        /path/to/checkout/binutils-gdb-git/gdb/main.c:1345
0x55a2f12d9f7b main
        /path/to/checkout/binutils-gdb-git/gdb/gdb.c:32
---------------------
A fatal error internal to GDB has been detected, further
debugging is not possible.  GDB will now terminate.

This is a bug, please report it.  For instructions, see:
<https://www.gnu.org/software/gdb/bugs/>.

zsh: segmentation fault  /foo/bin/bin/gdb

-------
This seems to be a regression from that which Debian packaged, where "gdb
--version" says "GNU gdb (Debian 10.1-1.7) 10.1.90.20210103-git", and where the
corresponding "document foo" gets me the somewhat more expected:
-------
(gdb) document foo
Undefined command: "foo".  Try "help".
(gdb) 
-------
(FWIW, I actually sourced a script, where I had the document and define
switched, but the crashing behavior is AFAICT identical.)

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[Bug cli/29800] Trying to "document" an undefined command causes crash

[simon.marchi at polymtl dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

Simon Marchi <simon.marchi at polymtl dot ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |good-first-bug
                 CC|                            |simon.marchi at polymtl dot ca

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[Bug cli/29800] Trying to "document" an undefined command causes crash

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at sourceware dot org
   Target Milestone|---                         |13.1

--- Comment #1 from Tom Tromey <tromey at sourceware dot org> ---
Regression.

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[Bug cli/29800] Trying to "document" an undefined command causes crash

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |tromey at sourceware dot org

--- Comment #2 from Tom Tromey <tromey at sourceware dot org> ---
Have a patch.

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[Bug cli/29800] Trying to "document" an undefined command causes crash

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

--- Comment #3 from Tom Tromey <tromey at sourceware dot org> ---
https://sourceware.org/pipermail/gdb-patches/2022-November/193967.html

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[Bug cli/29800] Trying to "document" an undefined command causes crash

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

--- Comment #4 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom Tromey <tromey@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b70e9270fbafd43a3fece0c7dd52cabd70854dfd

commit b70e9270fbafd43a3fece0c7dd52cabd70854dfd
Author: Tom Tromey <tromey@adacore.com>
Date:   Fri Nov 18 09:04:39 2022 -0700

    Fix crash in "document" command

    PR cli/29800 points out that "document" will now crash when the
    argument is an undefined command.  This is a regression due to the
    "document user-defined aliases" patch.

    Approved-By: Joel Brobecker <brobecker@adacore.com>
    Reviewed-By: Philippe Waroquiers <philippe.waroquiers@skynet.be>
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29800

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[Bug cli/29800] Trying to "document" an undefined command causes crash

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29800

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #5 from Tom Tromey <tromey at sourceware dot org> ---
Fixed.

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