Load from pickle without _cache

tests/test_url.py

@@ -1,4 +1,5 @@
 import sys
+import pickle
 import pytest
 from urllib.parse import SplitResult
 from multidict import MultiDict, MultiDictProxy
@@ -1355,3 +1356,28 @@ def test_semicolon_as_value():
     u = URL('http://127.0.0.1/?a=1%3Bb=2')
     assert len(u.query) == 1
     assert u.query['a'] == '1;b=2'
+
+
+# serialize
+
+def test_pickle():
+    u1 = URL('test')
+    hash(u1)
+    v = pickle.dumps(u1)
+    u2 = pickle.loads(v)
+    assert u1._cache
+    assert not u2._cache
+    assert hash(u1) == hash(u2)
+
+
+def test_default_style_state():
+    u = URL('test')
+    hash(u)
+    u.__setstate__((None, {
+        '_val': 'test',
+        '_strict': False,
+        '_cache': {'hash': 1},
+    }))
+    assert not u._cache
+    assert u._val == 'test'
+    assert u._strict is False

yarl/__init__.py

@@ -247,6 +247,18 @@ def __truediv__(self, name):
             self._val._replace(path=new_path, query='', fragment=''),
             encoded=True)
 
+    def __getstate__(self):
+        return self._val, self._strict
+
+    def __setstate__(self, state):
+        if state[0] is None and isinstance(state[1], dict):
+            # default style pickle
+            self._val = state[1]['_val']
+            self._strict = state[1]['_strict']
+        else:
+            self._val, self._strict = state
+        self._cache = {}
+
     def is_absolute(self):
         """A check for absolute URLs.