rfc3986 - default port

tests/test_url.py

@@ -1338,6 +1338,7 @@ def test_is_default_port_for_absolute_url_without_port():
 def test_is_default_port_for_absolute_url_with_default_port():
     url = URL("http://example.com:80")
     assert url.is_default_port()
+    assert str(url) == "http://example.com"
 
 
 def test_is_default_port_for_absolute_url_with_nondefault_port():
@@ -1548,7 +1549,7 @@ def test_parent_for_empty_url():
 
 def test_empty_value_for_query():
     url = URL("http://example.com/path").with_query({"a": ""})
-    assert str(url) == "http://example.com/path?a="
+    assert str(url) == "http://example.com/path?a"
 
 
 def test_none_value_for_query():

yarl/_url.py

@@ -292,6 +292,16 @@ def __str__(self):
         val = self._val
         if not val.path and self.is_absolute() and (val.query or val.fragment):
             val = val._replace(path="/")
+        if (port := self._get_port()) is None:
+            val = val._replace(
+                netloc=self._make_netloc(
+                    self.raw_user,
+                    self.raw_password,
+                    self.raw_host,
+                    port,
+                    encode_host=False,
+                )
+            )
         return urlunsplit(val)
 
     def __repr__(self):
@@ -437,19 +447,17 @@ def raw_authority(self):
         return self._val.netloc
 
     def _get_port(self):
-        """Port or "" if default port"""
+        """Port or None if default port"""
         port = self.port
         if self.scheme:
-            port = DEFAULT_PORTS.get(self.scheme, -1)
-            if port == self.port:
-                port = ""
-            elif port == -1:
+            p = DEFAULT_PORTS.get(self.scheme)
+            if p == self.port:
+                port = None
+            elif p is None:
                 with suppress(OSError):
-                    port = socket.getservbyname(self.scheme)
-                    if port == self.port:
-                        port = ""
-            else:
-                port = self.port
+                    p = socket.getservbyname(self.scheme)
+                    if p == self.port:
+                        port = None
         return port
 
     @cached_property
@@ -744,9 +752,7 @@ def _make_child(self, paths, encoded=False):
                     f"Appending path {path!r} starting from slash is forbidden"
                 )
             path = path if encoded else self._PATH_QUOTER(path)
-            segments = [
-                segment for segment in reversed(path.split("/")) if segment != "."
-            ]
+            segments = list(reversed(path.split("/")))
             if not segments:
                 continue
             # remove trailing empty segment for all but the last path