Make checking for liveness of global values more precise.

We can't just use a hash lookup because a global and a local reference
might refer to the same Lisp object.

* src/emacs-module.c (module_free_global_ref): More precise check for
global liveness.

* test/data/emacs-module/mod-test.c (Fmod_test_globref_invalid_free):
New test module function.
(emacs_module_init): Export it.

* test/src/emacs-module-tests.el
(module--test-assertions--globref-invalid-free): New unit test.

1 files changed, 8 insertions, 5 deletions

diff --git a/src/emacs-module.c b/src/emacs-module.c
index 02563a4b8b5..e4e7da088d7 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -468,6 +468,14 @@ module_free_global_ref (emacs_env *env, emacs_value global_value)
   Lisp_Object obj = value_to_lisp (global_value);
   ptrdiff_t i = hash_lookup (h, obj, NULL);
 
+  if (module_assertions)
+    {
+      ptrdiff_t n = 0;
+      if (! module_global_reference_p (global_value, &n))
+        module_abort ("Global value was not found in list of %"pD"d globals",
+                      n);
+    }
+
   if (i >= 0)
     {
       Lisp_Object value = HASH_VALUE (h, i);
@@ -476,11 +484,6 @@ module_free_global_ref (emacs_env *env, emacs_value global_value)
       if (--ref->refcount == 0)
         hash_remove_from_table (h, obj);
     }
-  else if (module_assertions)
-    {
-      module_abort ("Global value was not found in list of %"pD"d globals",
-                    h->count);
-    }
 }
 
 static enum emacs_funcall_exit