SF patch #693753: fix for bug 639806: default for dict.pop

(contributed by Michael Stone.)

3 files changed, 23 insertions, 5 deletions

diff --git a/Lib/UserDict.py b/Lib/UserDict.py
index fb9cdd5..6b5c9da 100644
--- a/Lib/UserDict.py
+++ b/Lib/UserDict.py
@@ -55,8 +55,8 @@ class UserDict:
         if not self.has_key(key):
             self[key] = failobj
         return self[key]
-    def pop(self, key):
-        return self.data.pop(key)
+    def pop(self, key, *args):
+        return self.data.pop(key, *args)
     def popitem(self):
         return self.data.popitem()
     def __contains__(self, key):
@@ -117,8 +117,16 @@ class DictMixin:
         except KeyError:
             self[key] = default
         return default
-    def pop(self, key):
-        value = self[key]
+    def pop(self, key, *args):
+        if len(args) > 1:
+            raise TypeError, "pop expected at most 2 arguments, got "\
+                              + repr(1 + len(args))
+        try:
+            value = self[key]
+        except KeyError:
+            if args:
+                return args[0]
+            raise
         del self[key]
         return value
     def popitem(self):
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index d571a02..f2a7ccd 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -643,10 +643,14 @@ else: raise TestFailed, "{}.pop(k) doesn't raise KeyError when dictionary is emp
 # see SF bug #689659
 x = 4503599627370496L
 y = 4503599627370496
-h = {x: 'anything', y: 'something else'} 
+h = {x: 'anything', y: 'something else'}
 if h[x] != h[y]:
     raise TestFailed, "long/int key should match"
 
+if d.pop(k, v) != v: raise TestFailed, "{}.pop(k, v) doesn't return default value"
+d[k] = v
+if d.pop(k, 1) != v: raise TestFailed, "{}.pop(k, v) doesn't find known key/value pair"
+
 d[1] = 1
 try:
     for i in d:
diff --git a/Lib/test/test_userdict.py b/Lib/test/test_userdict.py
index d3e8002..cb98308 100644
--- a/Lib/test/test_userdict.py
+++ b/Lib/test/test_userdict.py
@@ -139,6 +139,9 @@ class UserDictTest(unittest.TestCase):
         t = UserDict.UserDict(x=42)
         self.assertEqual(t.pop("x"), 42)
         self.assertRaises(KeyError, t.pop, "x")
+        self.assertEqual(t.pop("x", 1), 1)
+        t["x"] = 42
+        self.assertEqual(t.pop("x", 1), 42)
 
         # Test popitem
         t = UserDict.UserDict(x=42)
@@ -242,6 +245,9 @@ class UserDictMixinTest(unittest.TestCase):
         self.assertEqual(s.pop(10), 'ten')
         self.assert_(10 not in s)
         s[10] = 'ten'
+        self.assertEqual(s.pop("x", 1), 1)
+        s["x"] = 42
+        self.assertEqual(s.pop("x", 1), 42)
 
         # popitem
         k, v = s.popitem()