Support 'with'

--HG--
branch : ast-branch

1 files changed, 17 insertions, 9 deletions

diff --git a/coverage/parser.py b/coverage/parser.py
index d599bef9..a5e12d35 100644
--- a/coverage/parser.py
+++ b/coverage/parser.py
@@ -264,16 +264,17 @@ class PythonParser(object):
         return self._all_arcs
 
     def arcs(self):
-        aaa = AstArcAnalyzer(self.text)
-        arcs = aaa.collect_arcs()
+        if self._all_arcs is None:
+            aaa = AstArcAnalyzer(self.text)
+            arcs = aaa.collect_arcs()
 
-        arcs_ = set()
-        for l1, l2 in arcs:
-            fl1 = self.first_line(l1)
-            fl2 = self.first_line(l2)
-            if fl1 != fl2:
-                arcs_.add((fl1, fl2))
-        return arcs_
+            self._all_arcs = set()
+            for l1, l2 in arcs:
+                fl1 = self.first_line(l1)
+                fl2 = self.first_line(l2)
+                if fl1 != fl2:
+                    self._all_arcs.add((fl1, fl2))
+        return self._all_arcs
 
     def exit_counts(self):
         """Get a count of exits from that each line.
@@ -559,6 +560,13 @@ class AstArcAnalyzer(object):
         # TODO: orelse
         return exits
 
+    def handle_With(self, node):
+        start = self.line_for_node(node)
+        exits = self.add_body_arcs(node.body, from_line=start)
+        return exits
+
+    handle_AsyncWith = handle_With
+
     def handle_default(self, node):
         node_name = node.__class__.__name__
         if node_name not in ["Assign", "Assert", "AugAssign", "Expr", "Import", "Pass", "Print"]: