Construct self._val lazily

closes #172

tests/test_pickle.py

@@ -11,7 +11,6 @@ def test_pickle():
     v = pickle.dumps(u1)
     u2 = pickle.loads(v)
     assert u1._cache
-    assert not u2._cache
     assert hash(u1) == hash(u2)
 
 
@@ -20,5 +19,4 @@ def test_default_style_state():
     hash(u)
     val = ("test", "test", "test", "test", "test")
     u.__setstate__((None, {"_val": val, "_strict": False, "_cache": {"hash": 1}}))
-    assert not u._cache
     assert u._val == val

tests/test_url.py

@@ -2176,35 +2176,23 @@ def test_join_encoded_url():
 def test_parsing_populates_cache():
     """Test that parsing a URL populates the cache."""
     url = URL("http://user:password@example.com:80/path?a=b#frag")
-    assert url._cache["raw_user"] == "user"
-    assert url._cache["raw_password"] == "password"
-    assert url._cache["raw_host"] == "example.com"
-    assert url._cache["explicit_port"] == 80
-    assert url._cache["raw_query_string"] == "a=b"
-    assert url._cache["raw_fragment"] == "frag"
-    assert url._cache["scheme"] == "http"
+    c = url._cache
+    assert c["raw_user"] == "user"
+    assert c["raw_password"] == "password"
+    assert c["raw_host"] == "example.com"
+    assert c["explicit_port"] == 80
+    assert c["raw_query_string"] == "a=b"
+    assert c["raw_fragment"] == "frag"
+    assert c["scheme"] == "http"
+    assert c["raw_netloc"] == "user:password@example.com:80"
+    assert c["_path"] == "/path"
     assert url.raw_user == "user"
     assert url.raw_password == "password"
     assert url.raw_host == "example.com"
     assert url.explicit_port == 80
     assert url.raw_query_string == "a=b"
     assert url.raw_fragment == "frag"
     assert url.scheme == "http"
-    url._cache.clear()
-    assert url.raw_user == "user"
-    assert url.raw_password == "password"
-    assert url.raw_host == "example.com"
-    assert url.explicit_port == 80
-    assert url.raw_query_string == "a=b"
-    assert url.raw_fragment == "frag"
-    assert url.scheme == "http"
-    assert url._cache["raw_user"] == "user"
-    assert url._cache["raw_password"] == "password"
-    assert url._cache["raw_host"] == "example.com"
-    assert url._cache["explicit_port"] == 80
-    assert url._cache["raw_query_string"] == "a=b"
-    assert url._cache["raw_fragment"] == "frag"
-    assert url._cache["scheme"] == "http"
 
 
 @pytest.mark.parametrize(

tests/test_url_benchmarks.py

@@ -188,7 +188,7 @@ def test_raw_host_empty_cache(benchmark: BenchmarkFixture) -> None:
     @benchmark
     def _run() -> None:
         for _ in range(100):
-            url._cache = {}
+            url._cache.pop("raw_host", None)
             url.raw_host