If a type has a repr function but no print function, printing it now

calls the repr function.  When the refcount is bad, don't print
the object at all (chances of crashes).
Changes to checking and printing of references: the consistency
check is somewhat faster; don't print strings referenced once
(most occur in function's name lists).

1 files changed, 34 insertions, 5 deletions

diff --git a/Objects/object.c b/Objects/object.c
index 5f54b364b8..16053a9780 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -77,10 +77,28 @@ printobject(op, fp, flags)
 	}
 	else {
 		if (op->ob_refcnt <= 0)
-			fprintf(fp, "(refcnt %u):", op->ob_refcnt);
-		if (op->ob_type->tp_print == NULL)
-			fprintf(fp, "<%s object at %lx>",
-				op->ob_type->tp_name, (long)op);
+			fprintf(fp, "<refcnt %u at %lx>",
+				op->ob_refcnt, (long)op);
+		else if (op->ob_type->tp_print == NULL) {
+			if (op->ob_type->tp_repr == NULL) {
+				fprintf(fp, "<%s object at %lx>",
+					op->ob_type->tp_name, (long)op);
+			}
+			else {
+				object *s = reprobject(op);
+				if (s == NULL)
+					ret = -1;
+				else if (!is_stringobject(s)) {
+					err_setstr(TypeError,
+						   "repr not string");
+					ret = -1;
+				}
+				else {
+					fprintf(fp, "%s", getstringvalue(s));
+				}
+				XDECREF(s);
+			}
+		}
 		else
 			ret = (*op->ob_type->tp_print)(op, fp, flags);
 	}
@@ -252,6 +270,12 @@ UNREF(op)
 		fprintf(stderr, "UNREF negative refcnt\n");
 		abort();
 	}
+	if (op == &refchain ||
+	    op->_ob_prev->_ob_next != op || op->_ob_next->_ob_prev != op) {
+		fprintf(stderr, "UNREF invalid object\n");
+		abort();
+	}
+#ifdef SLOW_UNREF_CHECK
 	for (p = refchain._ob_next; p != &refchain; p = p->_ob_next) {
 		if (p == op)
 			break;
@@ -260,8 +284,10 @@ UNREF(op)
 		fprintf(stderr, "UNREF unknown object\n");
 		abort();
 	}
+#endif
 	op->_ob_next->_ob_prev = op->_ob_prev;
 	op->_ob_prev->_ob_next = op->_ob_next;
+	op->_ob_next = op->_ob_prev = NULL;
 }
 
 DELREF(op)
@@ -269,14 +295,17 @@ DELREF(op)
 {
 	UNREF(op);
 	(*(op)->ob_type->tp_dealloc)(op);
+	op->ob_type = NULL;
 }
 
 printrefs(fp)
 	FILE *fp;
 {
 	object *op;
-	fprintf(fp, "Remaining objects:\n");
+	fprintf(fp, "Remaining objects (except strings referenced once):\n");
 	for (op = refchain._ob_next; op != &refchain; op = op->_ob_next) {
+		if (op->ob_refcnt == 1 && is_stringobject(op))
+			continue; /* Will be printed elsewhere */
 		fprintf(fp, "[%d] ", op->ob_refcnt);
 		if (printobject(op, fp, 0) != 0)
 			err_clear();