gdb/python: make the executable_changed event available from Python

This commit makes the executable_changed observable available through
the Python API as an event.  There's nothing particularly interesting
going on here, it just follows the same pattern as many of the other
Python events we support.

The new event registry is called events.executable_changed, and this
emits an ExecutableChangedEvent object which has two attributes, a
gdb.Progspace called 'progspace', this is the program space in which
the executable changed, and a Boolean called 'reload', which is True
if the same executable changed on disk and has been reloaded, or is
False when a new executable has been loaded.

One interesting thing did come up during testing though, you'll notice
the test contains a setup_kfail call.  During testing I observed that
the executable_changed event would trigger twice when GDB restarted an
inferior.  However, the ExecutableChangedEvent object is identical for
both calls, so the wrong information is never sent out, we just see
one too many events.

I tracked this down to how the reload_symbols function (symfile.c)
takes care to also reload the executable, however, I've split fixing
this into a separate commit, so see the next commit for details.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/gdb/NEWS b/gdb/NEWS
index 2d57f52..fd7ab28 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -310,6 +310,11 @@ show tui mouse-events
      file name will have been partially resolved to an absolute file
      name.
 
+  ** A new executable_changed event registry is available.  This event
+     emits ExecutableChangedEvent objects, which have 'progspace' (a
+     gdb.Progspace) and 'reload' (a Boolean) attributes.  This event
+     is emitted when gdb.Progspace.executable_filename changes.
+
 *** Changes in GDB 13
 
 * MI version 1 is deprecated, and will be removed in GDB 14.