[binutils-gdb] gdb: change 'if' to gdb_assert in update_dprintf_command_list

[Andrew Burgess]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=3d42db971fc7cb0a5fe9b4526b12539019b5c27e

commit 3d42db971fc7cb0a5fe9b4526b12539019b5c27e
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Wed Apr 5 15:37:00 2023 +0100

    gdb: change 'if' to gdb_assert in update_dprintf_command_list
    
    I noticed in update_dprintf_command_list that we handle the case where
    the bp_dprintf style breakpoint doesn't have a format and args string.
    
    However, I don't believe such a situation is possible.  The obvious
    approach certainly already catches this case:
    
      (gdb) dprintf main
      Format string required
    
    If it is possible to create a dprintf breakpoint without a format and
    args string then I think we should be catching this case and handling
    it at creation time, rather than having GDB just ignore the situation
    later on.
    
    And so, I propose that we change the 'if' that ignores the case where
    the format/args string is empty, and instead assert that we do always
    have a format/args string.  The original code, that handled an empty
    format/args string has existed since commit e7e0cddfb0d4, which is
    when dprintf support was added to GDB.
    
    If I'm correct and this situation can't ever happen then there should
    be no user visible changes after this commit.

Diff:
---
 gdb/breakpoint.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 044d424d06c..8346c43925c 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -8529,8 +8529,9 @@ update_dprintf_command_list (struct breakpoint *b)
   const char *dprintf_args = b->extra_string.get ();
   gdb::unique_xmalloc_ptr<char> printf_line = nullptr;
 
-  if (!dprintf_args)
-    return;
+  /* Trying to create a dprintf breakpoint without a format and args
+     string should be detected at creation time.  */
+  gdb_assert (dprintf_args != nullptr);
 
   dprintf_args = skip_spaces (dprintf_args);