Fix a reference leak when a for-loop's "else:" branch contains a "break" for an outer loop.

Closes https://github.com/cython/cython/issues/5347

2 files changed, 42 insertions, 10 deletions

diff --git a/Cython/Compiler/Nodes.py b/Cython/Compiler/Nodes.py
index c5ddad0a6..457ae94ad 100644
--- a/Cython/Compiler/Nodes.py
+++ b/Cython/Compiler/Nodes.py
@@ -6723,23 +6723,28 @@ class _ForInStatNode(LoopNode, StatNode):
         code.set_loop_labels(old_loop_labels)
 
         if self.else_clause:
-            # in nested loops, the 'else' block can contain a
-            # 'continue' statement for the outer loop, but we may need
-            # to generate cleanup code before taking that path, so we
-            # intercept it here
-            orig_continue_label = code.continue_label
+            # In nested loops, the 'else' block can contain 'continue' or 'break'
+            # statements for the outer loop, but we may need to generate cleanup code
+            # before taking those paths, so we intercept them here.
+            orig_exit_labels = (code.continue_label, code.break_label)
             code.continue_label = code.new_label('outer_continue')
+            code.break_label = code.new_label('outer_break')
 
             code.putln("/*else*/ {")
             self.else_clause.generate_execution_code(code)
             code.putln("}")
 
-            if code.label_used(code.continue_label):
-                code.put_goto(break_label)
+            needs_goto_end = not self.else_clause.is_terminator
+            for exit_label, orig_exit_label in zip([code.continue_label, code.break_label], orig_exit_labels):
+                if not code.label_used(exit_label):
+                    continue
+                if needs_goto_end:
+                    code.put_goto(break_label)
+                    needs_goto_end = False
                 code.mark_pos(self.pos)
-                code.put_label(code.continue_label)
+                code.put_label(exit_label)
                 self.iterator.generate_disposal_code(code)
-                code.put_goto(orig_continue_label)
+                code.put_goto(orig_exit_label)
             code.set_loop_labels(old_loop_labels)
 
         code.mark_pos(self.pos)
diff --git a/tests/run/for_in_break_continue_T533.pyx b/tests/run/for_in_break_continue_T533.pyx
index 0baa9fa49..20dfa4caa 100644
--- a/tests/run/for_in_break_continue_T533.pyx
+++ b/tests/run/for_in_break_continue_T533.pyx
@@ -1,4 +1,6 @@
-# ticket: 533
+# mode: run
+# ticket: t533
+# ticket: gh1093
 
 def for_in():
     """
@@ -20,6 +22,7 @@ def for_in():
         break
     return i
 
+
 def for_from():
     """
     >>> for_from()
@@ -39,3 +42,27 @@ def for_from():
         print "BREAK", i
         break
     return i
+
+
+def for_in_break2(data, avoid):
+    """
+    >>> for_in_break2([1,2,3,None], avoid=[1,2,3])
+    3
+    >>> for_in_break2([1,2,3,None], avoid=[1])
+    1
+    >>> for_in_break2([1,2,3,None], avoid=[1])
+    1
+    """
+    data_iter = iter(data)
+    value = None
+    while 1:
+        match = next(data_iter)
+        if match is None:
+            break
+        for value in avoid:
+            if match == value:
+                break
+        else:
+            break
+
+    return value