From 4cc3e63e98b1adaaf6aedc09830569767d5eb653 Mon Sep 17 00:00:00 2001
From: "Karl O. Pinc" <kop@karlpinc.com>
Date: Thu, 21 Mar 2024 14:43:39 -0500
Subject: [PATCH] Use importlib.metadata instead of pkg_resources for
 entrypoint processing

---
 setup.py                   |  2 ++
 src/pgwui_common/plugin.py | 20 ++++++++++++----
 tests/test_plugin.py       | 47 +++++++++++++++++++++-----------------
 3 files changed, 43 insertions(+), 26 deletions(-)

diff --git a/setup.py b/setup.py
index cdd4ad6..98dc527 100644
--- a/setup.py
+++ b/setup.py
@@ -143,6 +143,8 @@ setup(
     # Run-time dependencies.
     install_requires=[
         'pgwui_core==' + version,
+        # for plugin.py's entrypoint processing.
+        'importlib_metadata > 3.6 ; python_version < "3.10"',
         'pyramid',
         'pyramid_beaker',
         'pyramid_mako',
diff --git a/src/pgwui_common/plugin.py b/src/pgwui_common/plugin.py
index ab7215f..f69bafc 100644
--- a/src/pgwui_common/plugin.py
+++ b/src/pgwui_common/plugin.py
@@ -22,7 +22,16 @@
 '''Plugin support library for PGWUI
 '''
 
-import pkg_resources
+import sys
+
+if sys.version_info < (3, 10):
+    import importlib_metadata
+
+    class importlib:
+        pass
+    setattr(importlib, 'metadata', importlib_metadata)
+else:
+    import importlib.metadata
 
 
 def get_component(module):
@@ -34,8 +43,8 @@ def get_component(module):
 def find_pgwui_components():
     '''Return list of all pgwui component names as strings
     '''
-    return [get_component(entry_point.resolve().__name__) for entry_point in
-            pkg_resources.iter_entry_points('pgwui.components')]
+    return [get_component(entry_point.module) for entry_point in
+            importlib.metadata.entry_points(group='pgwui.components')]
 
 
 def find_pgwui_check_settings():
@@ -43,7 +52,8 @@ def find_pgwui_check_settings():
     component
     '''
     check_settings = dict()
-    for entry_point in pkg_resources.iter_entry_points('pgwui.check_settings'):
-        callable = entry_point.resolve()
+    for entry_point in importlib.metadata.entry_points(
+            group='pgwui.check_settings'):
+        callable = entry_point.load()
         check_settings[get_component(callable.__module__)] = callable
     return check_settings
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index bd1fa8e..439bb5a 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -26,23 +26,16 @@ from pgwui_common import plugin
 
 
 # Helper classes
+# (We might want to mock this, but what module defines EntryPoint()?)
 class MockEntryPoint():
     def __init__(self, val):
+        self.module = val
         self.__module__ = val
-        self.__name__ = val
 
-    def resolve(self):
+    def load(self):
         return self
 
 
-class MockPkgResources():
-    def __init__(self, entry_points):
-        self.entry_points = entry_points
-
-    def iter_entry_points(self, *args):
-        return [MockEntryPoint(name) for name in self.entry_points]
-
-
 # get_component()
 
 @pytest.mark.unittest
@@ -59,33 +52,45 @@ mock_get_component = testing.make_mock_fixture(
 
 # find_pgwui_components()
 
+# Use late binding; eaiser since the module hierarchy is sometimes constructed
+# because importlib.metadata sometimes uses a compatibility module.
+mock_importlib_metadata_entry_points = testing.late_instance_mock_fixture(
+    'entry_points')
+
+
 @pytest.mark.unittest
-def test_find_pgwui_components(mock_get_component, monkeypatch):
-    '''Returns list of entry points via iter_entry_points()
+def test_find_pgwui_components(
+        mock_get_component, mock_importlib_metadata_entry_points):
+    '''Returns collection of entry points via entry_points()
     '''
-    entry_points = ['a', 'b', 'c']
+    entry_point_modules = ['a', 'b', 'c']
+    entry_points = [MockEntryPoint(mod) for mod in entry_point_modules]
 
     mock_get_component.side_effect = lambda x: x
-    monkeypatch.setattr(
-        plugin, 'pkg_resources', MockPkgResources(entry_points))
+    mocked_importlib_metadata_entry_points = (
+        mock_importlib_metadata_entry_points(plugin.importlib.metadata))
+    mocked_importlib_metadata_entry_points.return_value = entry_points
 
     result = plugin.find_pgwui_components()
 
-    assert result == entry_points
+    assert result == entry_point_modules
 
 
 # find_pgwui_check_settings
 @pytest.mark.unittest
-def test_find_pgwui_check_settings(mock_get_component, monkeypatch):
+def test_find_pgwui_check_settings(
+        mock_get_component, mock_importlib_metadata_entry_points):
     '''Returns a dict, keyed by name, of entry points
     '''
-    entry_points = ['a', 'b', 'c']
+    entry_point_modules = ['a', 'b', 'c']
+    entry_points = [MockEntryPoint(mod) for mod in entry_point_modules]
 
     mock_get_component.side_effect = lambda x: x
-    monkeypatch.setattr(
-        plugin, 'pkg_resources', MockPkgResources(entry_points))
+    mocked_importlib_metadata_entry_points = (
+        mock_importlib_metadata_entry_points(plugin.importlib.metadata))
+    mocked_importlib_metadata_entry_points.return_value = entry_points
 
     result = plugin.find_pgwui_check_settings()
 
     assert isinstance(result, dict)
-    assert list(result.keys()).sort() == entry_points.sort()
+    assert list(result.keys()).sort() == entry_point_modules.sort()
-- 
2.34.1