[binutils-gdb] gdb/record: add an assert in cmd_record_start

[binutils-gdb] gdb/record: add an assert in cmd_record_start

[Andrew Burgess]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6e4f0b3ea0d49c4fd11002a8074eb49e7838b4b2

commit 6e4f0b3ea0d49c4fd11002a8074eb49e7838b4b2
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Mon Apr 15 14:10:05 2024 +0100

    gdb/record: add an assert in cmd_record_start
    
    The 'record' command is both a prefix command AND an alias for 'target
    record-full'.  As it is a prefix command, if a user types:
    
      (gdb) record blah
    
    Then GDB will look for, and try to invoke the 'blah' sub-command.
    This will either succeed (if blah is found) or throw an error (if blah
    is not found).
    
    As such, the only way to invoke the 'record' command is like:
    
      (gdb) record
    
    It is impossible to pass arguments to the 'record' command.  As we
    know this is true then we can assert this in cmd_record_start.
    
    I added this assert because initially I was going to try forwarding
    ARGS from cmd_record_start to the 'target record-full' command, but
    then I realised passing arguments to 'record' was impossible.
    
    There should be no user visible changes after this commit.
    
    Approved-By: Tom Tromey <tom@tromey.com>

Diff:
---
 gdb/record.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gdb/record.c b/gdb/record.c
index 25a4c1e71b6..5b1093dd12e 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -260,11 +260,16 @@ show_record_debug (struct ui_file *file, int from_tty,
 	      value);
 }
 
-/* Alias for "target record".  */
+/* Alias for "target record-full".  */
 
 static void
 cmd_record_start (const char *args, int from_tty)
 {
+  /* As 'record' is a prefix command then if the user types 'record blah'
+     GDB will search for the 'blah' sub-command and either run that instead
+     of calling this function, or throw an error if 'blah' doesn't exist.
+     As a result, we only get here if no args are given.  */
+  gdb_assert (args == nullptr);
   execute_command ("target record-full", from_tty);
 }