Use importlib to load numba extensions

buildscripts/condarecipe.local/meta.yaml

@@ -35,6 +35,7 @@ requirements:
     - llvmlite 0.31.*
     - funcsigs                 # [py27]
     - singledispatch           # [py27]
+    - importlib-metadata       # [py27]
     # TBB devel version is to match TBB libs
     - tbb-devel >=2018.0.5     # [not ((armv6l or armv7l or aarch64) or (win and py27))]
   run:
@@ -45,6 +46,7 @@ requirements:
     - llvmlite 0.31.*
     - funcsigs                 # [py27]
     - singledispatch           # [py27]
+    - importlib-metadata       # [py27]
   run_constrained:
     # If TBB is present it must be at least this version from Anaconda due to
     # build flag issues triggering UB

buildscripts/incremental/setup_conda_environment.cmd

@@ -32,6 +32,7 @@ call activate %CONDA_ENV%
 if %PYTHON% LSS 3.4 (%CONDA_INSTALL% enum34)
 if %PYTHON% LSS 3.4 (%PIP_INSTALL% singledispatch)
 if %PYTHON% LSS 3.3 (%CONDA_INSTALL% -c numba funcsigs)
+if %PYTHON% LSS 3.8 (%PIP_INSTALL% importlib-metadata)
 @rem Install dependencies for building the documentation
 if "%BUILD_DOC%" == "yes" (%CONDA_INSTALL% sphinx pygments)
 if "%BUILD_DOC%" == "yes" (%PIP_INSTALL% sphinx_bootstrap_theme)

buildscripts/incremental/setup_conda_environment.sh

@@ -80,6 +80,8 @@ $CONDA_INSTALL -c numba llvmlite
 # Install enum34 and singledispatch for Python < 3.4
 if [ $PYTHON \< "3.4" ]; then $CONDA_INSTALL enum34; fi
 if [ $PYTHON \< "3.4" ]; then $PIP_INSTALL singledispatch; fi
+# Install importlib-metadata for Python < 3.8
+if [ $PYTHON \< "3.8" ]; then $PIP_INSTALL importlib-metadata; fi
 # Install funcsigs for Python < 3.3
 if [ $PYTHON \< "3.3" ]; then $CONDA_INSTALL -c numba funcsigs; fi
 # Install dependencies for building the documentation

numba/core/entrypoints.py

@@ -1,6 +1,9 @@
 import logging
 
-from pkg_resources import iter_entry_points
+try:
+    from importlib import metadata as importlib_metadata
+except ImportError:
+    import importlib_metadata
 
 _already_initialized = False
 logger = logging.getLogger(__name__)
@@ -18,7 +21,10 @@ def init_all():
     # Must put this here to avoid extensions re-triggering initialization
     _already_initialized = True
 
-    for entry_point in iter_entry_points('numba_extensions', 'init'):
-        logger.debug('Loading extension: %s', entry_point)
-        func = entry_point.load()
-        func()
+    for entry_point in importlib_metadata.entry_points().get(
+        'numba_extensions', tuple()
+    ):
+        if entry_point.name == 'init':
+            logger.debug('Loading extension: %s', entry_point)
+            func = entry_point.load()
+            func()

numba/tests/test_entrypoints.py

@@ -1,7 +1,10 @@
 import sys
-import types
+from unittest import mock
 
-import pkg_resources
+try:
+    from importlib import metadata as importlib_metadata
+except ImportError:
+    import importlib_metadata
 
 from numba.tests.support import TestCase
 
@@ -15,45 +18,38 @@ def test_init_entrypoint(self):
         # loosely based on Pandas test from:
         #   https://github.com/pandas-dev/pandas/pull/27488
 
-        # FIXME: Python 2 workaround because nonlocal doesn't exist
-        counters = {'init': 0}
-
-        def init_function():
-            counters['init'] += 1
-
-        mod = types.ModuleType("_test_numba_extension")
-        mod.init_func = init_function
+        mod = mock.Mock(__name__='_test_numba_extension')
 
         try:
             # will remove this module at the end of the test
             sys.modules[mod.__name__] = mod
 
             # We are registering an entry point using the "numba" package
-            # ("distribution" in pkg_resources-speak) itself, though these are
+            # ("distribution" in importlib-speak) itself, though these are
             # normally registered by other packages.
-            dist = "numba"
-            entrypoints = pkg_resources.get_entry_map(dist)
-            my_entrypoint = pkg_resources.EntryPoint(
-                "init", # name of entry point
-                mod.__name__, # module with entry point object
-                attrs=['init_func'], # name of entry point object
-                dist=pkg_resources.get_distribution(dist)
+            my_entrypoint = importlib_metadata.EntryPoint(
+                'init', '_test_numba_extension:init_func', 'numba_extensions',
             )
-            entrypoints.setdefault('numba_extensions',
-                                   {})['init'] = my_entrypoint
 
-            from numba.core import entrypoints
-            # Allow reinitialization
-            entrypoints._already_initialized = False
+            with mock.patch.object(
+                importlib_metadata,
+                'entry_points',
+                return_value={'numba_extensions': (my_entrypoint,)},
+            ):
+
+                from numba.core import entrypoints
+
+                # Allow reinitialization
+                entrypoints._already_initialized = False
 
-            entrypoints.init_all()
+                entrypoints.init_all()
 
-            # was our init function called?
-            self.assertEqual(counters['init'], 1)
+                # was our init function called?
+                mod.init_func.assert_called_once()
 
-            # ensure we do not initialize twice
-            entrypoints.init_all()
-            self.assertEqual(counters['init'], 1)
+                # ensure we do not initialize twice
+                entrypoints.init_all()
+                mod.init_func.assert_called_once()
         finally:
             # remove fake module
             if mod.__name__ in sys.modules:

requirements.txt

@@ -4,3 +4,4 @@ llvmlite>=0.31
 argparse
 funcsigs ; python_version < '3.4'
 singledispatch ; python_version < '3.4'
+importlib-metadata ; python_version < '3.8'