From 527173b872b7673a0d43fa042dab9f095b24181f Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sun, 25 Feb 2024 14:16:46 -0500
Subject: [PATCH 1/3] Give precedence to native traversable readers.

Ensure that standard library readers are replaced while third-party readers are passed along. Closes #295.
---
 importlib_resources/future/adapters.py | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/importlib_resources/future/adapters.py b/importlib_resources/future/adapters.py
index 56dea7c..3c2d0fb 100644
--- a/importlib_resources/future/adapters.py
+++ b/importlib_resources/future/adapters.py
@@ -1,3 +1,4 @@
+import contextlib
 import pathlib
 from contextlib import suppress
 from types import SimpleNamespace
@@ -15,7 +16,18 @@ class TraversableResourcesLoader(_adapters.TraversableResourcesLoader):
     """
 
     def get_resource_reader(self, name):
-        return self._standard_reader() or super().get_resource_reader(name)
+        with contextlib.suppress(Exception):
+            return self._block_standard(super().get_resource_reader(name))
+        return self._standard_reader()
+
+    def _block_standard(self, reader):
+        """
+        If the reader is from the standard library, raise an exception to
+        allow likely newer implementations in this library to take precedence.
+        """
+        if reader.__class__.__module__.startswith('importlib.resources.'):
+            raise RuntimeError("Reader blocked to be superseded.")
+        return reader
 
     def _standard_reader(self):
         return self._zip_reader() or self._namespace_reader() or self._file_reader()

From a7b1b802a29d3fa35f59162dd4a085cd38513d6e Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Wed, 6 Mar 2024 17:49:53 -0500
Subject: [PATCH 2/3] Re-implement _block_standard as a wrapper function around
 _adapters.TraversableResourcesLoader and ensure that the known standard
 readers are replaced by readers from importlib_resources.

---
 importlib_resources/future/adapters.py | 51 +++++++++++++++++++-------
 1 file changed, 38 insertions(+), 13 deletions(-)

diff --git a/importlib_resources/future/adapters.py b/importlib_resources/future/adapters.py
index 3c2d0fb..9aa5b5e 100644
--- a/importlib_resources/future/adapters.py
+++ b/importlib_resources/future/adapters.py
@@ -1,4 +1,4 @@
-import contextlib
+import functools
 import pathlib
 from contextlib import suppress
 from types import SimpleNamespace
@@ -6,6 +6,39 @@
 from .. import readers, _adapters
 
 
+def _block_standard(reader_getter):
+    """
+    Wrap _adapters.TraversableResourcesLoader.get_resource_reader
+    and intercept any standard library readers.
+    """
+
+    @functools.wraps(reader_getter)
+    def wrapper(*args, **kwargs):
+        """
+        If the reader is from the standard library, return None to allow
+        allow likely newer implementations in this library to take precedence.
+        """
+        try:
+            reader = reader_getter(*args, **kwargs)
+        except NotADirectoryError:
+            # MultiplexedPath may fail on zip subdirectory
+            return
+        # Python 3.10+
+        if reader.__class__.__module__.startswith('importlib.resources.'):
+            return
+        # Python 3.8, 3.9
+        if isinstance(reader, _adapters.CompatibilityFiles) and (
+            reader.spec.loader.__class__.__module__.startswith('zipimport')
+            or reader.spec.loader.__class__.__module__.startswith(
+                '_frozen_importlib_external'
+            )
+        ):
+            return
+        return reader
+
+    return wrapper
+
+
 class TraversableResourcesLoader(_adapters.TraversableResourcesLoader):
     """
     Adapt loaders to provide TraversableResources and other
@@ -16,18 +49,10 @@ class TraversableResourcesLoader(_adapters.TraversableResourcesLoader):
     """
 
     def get_resource_reader(self, name):
-        with contextlib.suppress(Exception):
-            return self._block_standard(super().get_resource_reader(name))
-        return self._standard_reader()
-
-    def _block_standard(self, reader):
-        """
-        If the reader is from the standard library, raise an exception to
-        allow likely newer implementations in this library to take precedence.
-        """
-        if reader.__class__.__module__.startswith('importlib.resources.'):
-            raise RuntimeError("Reader blocked to be superseded.")
-        return reader
+        return (
+            _block_standard(super().get_resource_reader)(name)
+            or self._standard_reader()
+        )
 
     def _standard_reader(self):
         return self._zip_reader() or self._namespace_reader() or self._file_reader()

From 6d48bc93d76431b5538250d236c1c54c53f0fdcd Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Wed, 6 Mar 2024 17:54:26 -0500
Subject: [PATCH 3/3] Add news fragment.

---
 newsfragments/295.feature.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 newsfragments/295.feature.rst

diff --git a/newsfragments/295.feature.rst b/newsfragments/295.feature.rst
new file mode 100644
index 0000000..3d74253
--- /dev/null
+++ b/newsfragments/295.feature.rst
@@ -0,0 +1 @@
+Future compatibility adapters now ensure that standard library readers are replaced without overriding non-standard readers.