[Bug 3185009]: Keep references to resolved object variables so that an unset doesn't leave any dangling pointers for code to trip over.

1 files changed, 16 insertions, 0 deletions

diff --git a/generic/tclOOMethod.c b/generic/tclOOMethod.c
index 44eb083..4f29337 100644
--- a/generic/tclOOMethod.c
+++ b/generic/tclOOMethod.c
@@ -1055,6 +1055,14 @@ ProcedureMethodCompiledVarConnect(
     }
     if (cacheIt) {
 	infoPtr->cachedObjectVar = TclVarHashGetValue(hPtr);
+
+	/*
+	 * We must keep a reference to the variable so everything will
+	 * continue to work correctly even if it is unset; being unset does
+	 * not end the life of the variable at this level. [Bug 3185009]
+	 */
+
+	VarHashRefCount(infoPtr->cachedObjectVar)++;
     }
     return TclVarHashGetValue(hPtr);
 }
@@ -1065,6 +1073,14 @@ ProcedureMethodCompiledVarDelete(
 {
     OOResVarInfo *infoPtr = (OOResVarInfo *) rPtr;
 
+    /*
+     * Release the reference to the variable if we were holding it.
+     */
+
+    if (infoPtr->cachedObjectVar) {
+	VarHashRefCount(infoPtr->cachedObjectVar)--;
+	TclCleanupVar((Var *) infoPtr->cachedObjectVar, NULL);
+    }
     Tcl_DecrRefCount(infoPtr->variableObj);
     ckfree((char *) infoPtr);
 }