Fix bug introduced by SF patch #643835, Set Next Statement for Python debuggers
blockstack_top could be 0 when blockstack[blockstack_top-1]
was referenced (ie blockstack[-1]) which crashed on hpux.
Patch & fix by Richie Hindle
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index b9a4812..9123d94 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -184,6 +184,7 @@
break;
case POP_BLOCK:
+ assert(blockstack_top > 0);
setup_op = code[blockstack[blockstack_top-1]];
if (setup_op == SETUP_FINALLY) {
in_finally[blockstack_top-1] = 1;
@@ -196,10 +197,13 @@
case END_FINALLY:
/* Ignore END_FINALLYs for SETUP_EXCEPTs - they exist
* in the bytecode but don't correspond to an actual
- * 'finally' block. */
- setup_op = code[blockstack[blockstack_top-1]];
- if (setup_op == SETUP_FINALLY) {
- blockstack_top--;
+ * 'finally' block. (If blockstack_top is 0, we must
+ * be seeing such an END_FINALLY.) */
+ if (blockstack_top > 0) {
+ setup_op = code[blockstack[blockstack_top-1]];
+ if (setup_op == SETUP_FINALLY) {
+ blockstack_top--;
+ }
}
break;
}
@@ -233,6 +237,10 @@
}
}
+ /* Verify that the blockstack tracking code didn't get lost. */
+ assert(blockstack_top == 0);
+
+ /* After all that, are we jumping into / out of a 'finally' block? */
if (new_lasti_setup_addr != f_lasti_setup_addr) {
PyErr_SetString(PyExc_ValueError,
"can't jump into or out of a 'finally' block");