Merge pull request #65 from lsst/tickets/DM-35695

doc/changes/DM-35695.bugfix.rst

@@ -0,0 +1 @@
+Fixed problem where a fragment associated with a schemeless URI was erroneously being quoted.

python/lsst/resources/_resourcePath.py

@@ -166,14 +166,21 @@ def __new__(
                 if ESCAPES_RE.search(uri):
                     log.warning("Possible double encoding of %s", uri)
                 else:
-                    uri = urllib.parse.quote(uri)
-                    # Special case hash since we must support fragments
-                    # even in schemeless URIs -- although try to only replace
-                    # them in file part and not directory part
-                    if ESCAPED_HASH in uri:
+                    # Fragments are generally not encoded so we must search
+                    # for the fragment boundary ourselves. This is making
+                    # an assumption that the filename does not include a "#"
+                    # and also that there is no "/" in the fragment itself.
+                    to_encode = uri
+                    fragment = ""
+                    if "#" in uri:
                         dirpos = uri.rfind("/")
-                        # Do replacement after this /
-                        uri = uri[: dirpos + 1] + uri[dirpos + 1 :].replace(ESCAPED_HASH, "#")
+                        trailing = uri[dirpos + 1 :]
+                        hashpos = trailing.rfind("#")
+                        if hashpos != -1:
+                            fragment = trailing[hashpos:]
+                            to_encode = uri[: dirpos + hashpos + 1]
+
+                    uri = urllib.parse.quote(to_encode) + fragment
 
             parsed = urllib.parse.urlparse(uri)
         elif isinstance(uri, urllib.parse.ParseResult):

tests/test_schemeless.py

@@ -56,6 +56,14 @@ def test_creation(self) -> None:
         file_uri = ResourcePath(relative + "#frag", root=prefix_uri)
         self.assertEqual(str(file_uri), f"file://{prefix_uri.ospath}{relative}#frag")
 
+        # Fragments should not be encoded.
+        relative_uri = ResourcePath(relative + "#a,b", forceAbsolute=False)
+        self.assertEqual(str(relative_uri), f"{relative}#a,b")
+
+        # file URI with # in directory name does not encode fragment.
+        file_uri = ResourcePath("./relati#ve/file.yaml#a,v", root=prefix_uri)
+        self.assertEqual(str(file_uri), f"file://{prefix_uri.ospath}relati%23ve/file.yaml#a,v")
+
         # For historical reasons a a root can not be anything other
         # than a file. This does not really make sense in the general
         # sense but can be implemented using uri.join().