jim: fix sometimes overly zealous garbage collection

When checking for "weak" references where the only reference is in the
command hash table, need to check the reference count of the key in the hash
table (this is the command name), not the reference count of the object
we are using to look up the command. Without this it is possible that a reference
(typically a lambda) will be collected even though there is still a reference to it.

Signed-off-by: Steve Bennett <steveb@workware.net.au>

1 files changed, 6 insertions, 3 deletions

diff --git a/jim.c b/jim.c
index 893dff9..d6005d8 100644
--- a/jim.c
+++ b/jim.c
@@ -5527,11 +5527,14 @@ int Jim_Collect(Jim_Interp *interp)
                 /* But if this is a command in the command table with refCount 1
                  * don't mark it since it can be deleted.
                  */
-                if (p == str && objPtr->refCount == 1 && Jim_FindHashEntry(&interp->commands, objPtr)) {
+                if (p == str) {
+                    Jim_HashEntry *he = Jim_FindHashEntry(&interp->commands, objPtr);
+                    if (he && ((Jim_Obj *)Jim_GetHashEntryKey(he))->refCount == 1) {
 #ifdef JIM_DEBUG_GC
-                    printf("No MARK: %lu - command with refcount=1\n", id);
+                        printf("No MARK: %lu - command with refcount=1\n", idp);
 #endif
-                    break;
+                        break;
+                    }
                 }
                 Jim_AddHashEntry(&marks, &id, objPtr);
 #ifdef JIM_DEBUG_GC