[Bug python/16324] New: py-finishbreakpoint.c incorrect frame_id_eq

[Bug python/16324] New: py-finishbreakpoint.c incorrect frame_id_eq

[jan.kratochvil at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16324

            Bug ID: 16324
           Summary: py-finishbreakpoint.c incorrect frame_id_eq
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: python
          Assignee: unassigned at sourceware dot org
          Reporter: jan.kratochvil at redhat dot com

if (frame_id_eq (frame_id, null_frame_id))
                PyErr_SetString (PyExc_ValueError,
                                 _("Invalid ID for the `frame' object."));

it can never happen as frame_id_eq (null_frame_id, null_frame_id) is false:
     /* Like a NaN, if either ID is invalid, the result is false.
+
  /* Make the sentinel frame's ID valid, but invalid.  That way all
     comparisons with it should fail.  */
  frame->this_id.p = 1;
  frame->this_id.value = null_frame_id;

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[Bug python/16324] py-finishbreakpoint.c incorrect frame_id_eq

[pmuldoon at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16324

Phil Muldoon <pmuldoon at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |pmuldoon at redhat dot com
           Assignee|unassigned at sourceware dot org   |pmuldoon at redhat dot com

--- Comment #1 from Phil Muldoon <pmuldoon at redhat dot com> ---
It seems the correct test here is to use frame_id_p which checks if a valid
stack is found (with a simple check to frame_id.stack_status !=
FID_STACK_INVALID). It also checks the frame_id is not an outer frame id.

There is no explicit check for a null_frame_id, which I found odd. get_frame_id
can return a null_frame_id, but lots of callers don't check the return so there
is a latent bug there too.

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[Bug python/16324] py-finishbreakpoint.c incorrect frame_id_eq

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16324

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|pmuldoon at redhat dot com         |tromey at sourceware dot org
                 CC|                            |tromey at sourceware dot org

--- Comment #3 from Tom Tromey <tromey at sourceware dot org> ---
Going to send the patch.

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[Bug python/16324] py-finishbreakpoint.c incorrect frame_id_eq

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16324

--- 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=04ea6b63141c43d9e96999e16917358088556fdd

commit 04ea6b63141c43d9e96999e16917358088556fdd
Author: Tom Tromey <tom@tromey.com>
Date:   Sun Jun 5 10:22:40 2022 -0600

    Remove dead code from py-finishbreakpoint.c

    PR python/16324 points out that comparing a frame id to null_frame_id
    can never succeed, and proposes simply removing the dead code.  That
    is what this patch does.

    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=16324

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[Bug python/16324] py-finishbreakpoint.c incorrect frame_id_eq

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16324

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |13.1

--- Comment #5 from Tom Tromey <tromey at sourceware dot org> ---
Finally checked this in.

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