[glib: 1/2] gsignal: Change signal instance ref semantics under static analysis

[Philip Withnall <pwithnall src gnome org>]

commit 95d548ab03aab59687a3bafd4c9863559d7824ea
Author: Philip Withnall <pwithnall endlessos org>
Date:   Tue Jun 21 12:16:02 2022 +0100

    gsignal: Change signal instance ref semantics under static analysis
    
    As with commit 0932f71460a93a, which did this for refs/unrefs of the
    object in `g_object_notify()`, we need to do a similar thing for
    refs/unrefs of the instance with `g_signal_emit()`, for all the same
    reasons.
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>

 gobject/gsignal.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/gobject/gsignal.c b/gobject/gsignal.c
index ddd23fb738..aeb60b2ba0 100644
--- a/gobject/gsignal.c
+++ b/gobject/gsignal.c
@@ -3402,7 +3402,16 @@ g_signal_emit_valist (gpointer instance,
 
          if (closure != NULL)
            {
+              /*
+               * Coverity doesn’t understand the paired ref/unref here and seems
+               * to ignore the ref, thus reports every call to g_signal_emit()
+               * as causing a double-free. That’s incorrect, but I can’t get a
+               * model file to work for avoiding the false positives, so instead
+               * comment out the ref/unref when doing static analysis.
+               */
+#ifndef __COVERITY__
              g_object_ref (instance);
+#endif
              _g_closure_invoke_va (closure,
                                    return_accu,
                                    instance,
@@ -3452,8 +3461,11 @@ g_signal_emit_valist (gpointer instance,
          
          TRACE(GOBJECT_SIGNAL_EMIT_END(signal_id, detail, instance, instance_type));
 
+          /* See comment above paired ref above */
+#ifndef __COVERITY__
           if (closure != NULL)
             g_object_unref (instance);
+#endif
 
          return;
        }