Don't create a new URL if fragment unchanged (#384)

CHANGES.rst

@@ -18,6 +18,8 @@ CHANGES
 
 * Fix quoting of plus in path by pure python version (#339)
 
+* Don't create a new URL if fragment is unchanged (#292)
+
 1.3.0 (2018-12-11)
 ------------------
 

setup.cfg

@@ -12,7 +12,7 @@ junit_suite_name = yarl_test_suite
 
 
 [flake8]
-ignore = E301,E302,E704,W503,W504
+ignore = E301,E302,E704,W503,W504,F811
 max-line-length = 88
 
 [mypy]

tests/test_url.py

@@ -668,6 +668,18 @@ def test_with_fragment_None():
     assert str(url2) == "http://example.com/path"
 
 
+def test_with_fragment_None_matching():
+    url = URL("http://example.com/path")
+    url2 = url.with_fragment(None)
+    assert url is url2
+
+
+def test_with_fragment_matching():
+    url = URL("http://example.com/path#frag")
+    url2 = url.with_fragment("frag")
+    assert url is url2
+
+
 def test_with_fragment_bad_type():
     url = URL("http://example.com")
     with pytest.raises(TypeError):

yarl/__init__.py

@@ -913,12 +913,14 @@ def with_fragment(self, fragment):
         """
         # N.B. doesn't cleanup query/fragment
         if fragment is None:
-            fragment = ""
+            raw_fragment = ""
         elif not isinstance(fragment, str):
             raise TypeError("Invalid fragment type")
-        return URL(
-            self._val._replace(fragment=self._FRAGMENT_QUOTER(fragment)), encoded=True
-        )
+        else:
+            raw_fragment = self._FRAGMENT_QUOTER(fragment)
+        if self.raw_fragment == raw_fragment:
+            return self
+        return URL(self._val._replace(fragment=raw_fragment), encoded=True)
 
     def with_name(self, name):
         """Return a new URL with name (last part of path) replaced.

yarl/__init__.pyi

@@ -68,11 +68,11 @@ class URL:
     def with_path(self, path: str, *, encoded: bool = ...) -> URL: ...
     @overload
     def with_query(self, query: Query) -> URL: ...
-    @overload  # noqa: F811
+    @overload
     def with_query(self, **kwargs: QueryVariable) -> URL: ...
     @overload
     def update_query(self, query: Query) -> URL: ...
-    @overload  # noqa: F811
+    @overload
     def update_query(self, **kwargs: QueryVariable) -> URL: ...
     def with_fragment(self, fragment: Optional[str]) -> URL: ...
     def with_name(self, name: str) -> URL: ...