Pacify GCC 12 in default developer build

This lets ‘./configure; make’ work on Fedora 36 x86-64 from a Git
checkout without generating false-alarm warnings.
* lib-src/etags.c (main): There appeared to be false alarm with
GCC 12.  However, the code was wrong anyway, as it mishandled file
names containing "'" so fix that bug.  This pacifies GCC.
(mercury_decl): Omit tests ‘s + pos != NULL’ that were apparently
intended to be ‘s[pos] != '\0'’ but which were miscoded to always
be true and which were mostly not needed anyway.  In one place,
though, a test was needed, so fix that by using strchr instead.
* src/alloc.c (lisp_free) [!GC_MALLOC_CHECK]:
* src/term.c (Fsuspend_tty): Don’t look at a pointer after freeing
it, even just to test it for equality with some other pointer, as
this has undefined behavior in C and GCC 12 diagnoses this.
* src/dbusbind.c (xd_read_message_1): Rework the code a bit
so that it has fewer tests.  This pacifies GCC 12 which was
complaining incorrectly about dereferencing a null pointer.
* src/intervals.c (copy_properties): Remove an eassume that should
no longer be needed even to pacify older GCCs, due to ...
* src/intervals.h (split_interval_left): ... this addition of
ATTRIBUTE_RETURNS_NONNULL to pacify a GCC 12 warning about
dereferencing a null pointer.
* src/regex-emacs.c (EXTEND_BUFFER): Use negative values rather
than auxiliary booleans to indicate null pointers.  This pacifies
GCC 12 false alarms about using uninitialized variables.
* src/xdisp.c (clear_position): New function.
(append_space_for_newline, extend_face_to_end_of_line):
Use it to work around false alarms from GCC 12.
(display_and_set_cursor): Add an UNINIT to pacify GCC 12.
* src/xterm.c (x_draw_glyphless_glyph_string_foreground):
Defend against hypothetical bad code elsewhere;
this also pacifies GCC 12.
(x_term_init): Use fixed-size auto array rather than alloca,
as the array is small; this also pacifies GCC 12.

1 files changed, 21 insertions, 20 deletions

diff --git a/src/dbusbind.c b/src/dbusbind.c
index 7cfdbbe23cf..943a4aff8e7 100644
--- a/src/dbusbind.c
+++ b/src/dbusbind.c
@@ -1690,29 +1690,30 @@ xd_read_message_1 (DBusConnection *connection, Lisp_Object bus)
       value = Fgethash (key, Vdbus_registered_objects_table, Qnil);
 
       /* Loop over the registered functions.  Construct an event.  */
-      while (!NILP (value))
+      for (; !NILP (value); value = CDR_SAFE (value))
         {
           key = CAR_SAFE (value);
+          Lisp_Object key_uname = CAR_SAFE (key);
           /* key has the structure (UNAME SERVICE PATH HANDLER).  */
-          if (((uname == NULL)
-               || (NILP (CAR_SAFE (key)))
-               || (strcmp (uname, SSDATA (CAR_SAFE (key))) == 0))
-              && ((path == NULL)
-                  || (NILP (CAR_SAFE (CDR_SAFE (CDR_SAFE (key)))))
-                  || (strcmp (path,
-                              SSDATA (CAR_SAFE (CDR_SAFE (CDR_SAFE (key)))))
-                      == 0))
-              && (!NILP (CAR_SAFE (CDR_SAFE (CDR_SAFE (CDR_SAFE (key)))))))
-            {
-              EVENT_INIT (event);
-              event.kind = DBUS_EVENT;
-              event.frame_or_window = Qnil;
-              /* Handler.  */
-              event.arg
-                = Fcons (CAR_SAFE (CDR_SAFE (CDR_SAFE (CDR_SAFE (key)))), args);
-              break;
-            }
-          value = CDR_SAFE (value);
+          if (uname && !NILP (key_uname)
+              && strcmp (uname, SSDATA (key_uname)) != 0)
+            continue;
+          Lisp_Object key_service_etc = CDR_SAFE (key);
+          Lisp_Object key_path_etc = CDR_SAFE (key_service_etc);
+          Lisp_Object key_path = CAR_SAFE (key_path_etc);
+          if (path && !NILP (key_path)
+              && strcmp (path, SSDATA (key_path)) != 0)
+            continue;
+          Lisp_Object handler = CAR_SAFE (CDR_SAFE (key_path_etc));
+          if (NILP (handler))
+            continue;
+
+          /* Construct an event and exit the loop.  */
+          EVENT_INIT (event);
+          event.kind = DBUS_EVENT;
+          event.frame_or_window = Qnil;
+          event.arg = Fcons (handler, args);
+          break;
         }
 
       if (NILP (value))