gdb/622: clear current breakpoint in command-list problem

[brobecker at gnat dot com]

>Number:         622
>Category:       gdb
>Synopsis:       clear current breakpoint in command-list problem
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jul 31 12:18:01 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Joel Brobecker
>Release:        unknown-1.0
>Organization:
>Environment:
Platform independent. Reproduced on x86-linux, and sparc-solaris.
GDB 2002-07-27-cvs.
>Description:
Using the program in the gdb.base/commands.exp testcase, the following
session shows that clearing the current breakpoint inside its commands
list causes a memory-corruption problem:

      (gdb) b factorial
      Breakpoint 1 at 0x8048582: file ./gdb.base/run.c, line 77.
      (gdb) commands
      Type commands for when breakpoint 1 is hit, one per line.
      End with a line saying just "end".
      >silent
      >printf "factorial command-list executed\n"
      >clear factorial
      >cont
      >end
      (gdb) run 1
      Starting program: [...]/gdb.base/commands 1
      factorial command-list executed
      warning: Invalid control type in command structure.      <<<--- (1)
      (gdb)

(1) shows that the command-list becomes corrupted, and as a consequence,
the execution is not resumed.  Instead, the expected output from the run
command is:

      Starting program: [...]/gdb.base/run 1
      factorial command-list executed
      1

      Program exited normally.
      (gdb)
>How-To-Repeat:

>Fix:
The fix consists in making a duplicate of the commands-list
and execute this copy. I will send a patch to gdb-patches
shortly.
>Release-Note:
>Audit-Trail:
>Unformatted: