py: Handle case of return within the finally block of try-finally.

Addresses issue #1636.

1 files changed, 8 insertions, 0 deletions

diff --git a/py/vm.c b/py/vm.c
index 8bf59f1e0..8c7c2265e 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -1032,6 +1032,14 @@ unwind_jump:;
 
                 ENTRY(MP_BC_RETURN_VALUE):
                     MARK_EXC_IP_SELECTIVE();
+                    // These next 3 lines pop a try-finally exception handler, if one
+                    // is there on the exception stack.  Without this the finally block
+                    // is executed a second time when the return is executed, because
+                    // the try-finally exception handler is still on the stack.
+                    // TODO Possibly find a better way to handle this case.
+                    if (currently_in_except_block) {
+                        POP_EXC_BLOCK();
+                    }
 unwind_return:
                     while (exc_sp >= exc_stack) {
                         if (MP_TAGPTR_TAG1(exc_sp->val_sp)) {