Unify plugin loading

.editorconfig

@@ -33,3 +33,7 @@ max_line_length = 88
 # tab indentation
 [Makefile]
 indent_style = tab
+
+[*.{cfg,ini}]
+indent_style = space
+indent_size = 4

rdflib/plugin.py

@@ -50,8 +50,10 @@
     overload,
 )
 
-if TYPE_CHECKING:
-    from pkg_resources import EntryPoint
+if sys.version_info < (3, 8):
+    from importlib_metadata import entry_points, EntryPoint
+else:
+    from importlib.metadata import entry_points, EntryPoint
 
 __all__ = ["register", "get", "plugins", "PluginException", "Plugin", "PKGPlugin"]
 
@@ -127,20 +129,17 @@ def get(name: str, kind: Type[PluginT]) -> Type[PluginT]:
     return p.getClass()
 
 
-if sys.version_info < (3, 8):
-    from importlib_metadata import entry_points
-else:
-    from importlib.metadata import entry_points
-
 all_entry_points = entry_points()
 if hasattr(all_entry_points, "select"):
     for entry_point, kind in rdflib_entry_points.items():
         for ep in all_entry_points.select(group=entry_point):
             _plugins[(ep.name, kind)] = PKGPlugin(ep.name, kind, ep)
 else:
     # Prior to Python 3.10, this returns a dict instead of the selection interface, which is slightly slower
+    if TYPE_CHECKING:
+        assert isinstance(all_entry_points, dict)
     for entry_point, kind in rdflib_entry_points.items():
-        for ep in all_entry_points.get(entry_point, []):  # type: ignore[union-attr]
+        for ep in all_entry_points.get(entry_point, []):
             _plugins[(ep.name, kind)] = PKGPlugin(ep.name, kind, ep)
 
 

rdflib/plugins/sparql/__init__.py

@@ -31,6 +31,7 @@
 PLUGIN_ENTRY_POINT = "rdf.plugins.sparqleval"
 
 import sys
+from typing import TYPE_CHECKING, Any
 from . import parser
 from . import operators
 from . import parserutils
@@ -47,10 +48,12 @@
     from importlib.metadata import entry_points
 
 all_entry_points = entry_points()
-if isinstance(all_entry_points, dict):
-    # Prior to Python 3.10, this returns a dict instead of the selection interface
-    for ep in all_entry_points.get(PLUGIN_ENTRY_POINT, []):
+if hasattr(all_entry_points, "select"):
+    for ep in all_entry_points.select(group=PLUGIN_ENTRY_POINT):
         CUSTOM_EVALS[ep.name] = ep.load()
 else:
-    for ep in all_entry_points.select(group=PLUGIN_ENTRY_POINT):
+    # Prior to Python 3.10, this returns a dict instead of the selection interface
+    if TYPE_CHECKING:
+        assert isinstance(all_entry_points, dict)
+    for ep in all_entry_points.get(PLUGIN_ENTRY_POINT, []):
         CUSTOM_EVALS[ep.name] = ep.load()

setup.cfg

@@ -30,10 +30,11 @@ disallow_subclassing_any = False
 warn_unreachable = True
 warn_unused_ignores = True
 
-[mypy-rdflib.plugin]
-# There is one type ignore in rdflib.plugin which is not needed on python 3.10
-# but is needed on earlier versions, so this does not work for that module.
-warn_unused_ignores = False
+# This is here to exclude the setup.py files in test plugins because these
+# confuse mypy as mypy think they are the same module.
+exclude = (?x)(
+    ^.*test/plugins/.*/setup.py$
+  )
 
 [tool:pytest]
 addopts =

test/plugins/parser/example/rdflib/plugin/parser/__init__.py

@@ -0,0 +1,28 @@
+from typing import TYPE_CHECKING, Set, Tuple
+from rdflib.parser import Parser
+
+
+if TYPE_CHECKING:
+    from rdflib.parser import InputSource
+    from rdflib.graph import Graph
+    from rdflib.namespace import Namespace
+    from rdflib.term import Identifier
+
+
+class ExampleParser(Parser):
+    def __init__(self):
+        super().__init__()
+
+    def parse(self, source: "InputSource", sink: "Graph"):
+        for triple in self.constant_output():
+            sink.add(triple)
+
+    @classmethod
+    def namespace(cls) -> "Namespace":
+        return Namespace("example:rdflib:plugin:parser:")
+
+    @classmethod
+    def constant_output(cls) -> Set[Tuple["Identifier", "Identifier", "Identifier"]]:
+        return {(cls.namespace().subj, cls.namespace().pred, cls.namespace().obj)}
+
+from rdflib.namespace import Namespace

test/plugins/parser/setup.cfg

@@ -0,0 +1,17 @@
+# https://setuptools.pypa.io/en/latest/userguide/declarative_config.html
+# https://setuptools.pypa.io/en/latest/references/keywords.html
+[metadata]
+name = example.rdflib.plugin.parser
+version = 0.0.0
+
+[options]
+packages = find_namespace:
+
+[options.packages.find]
+include =
+    example.rdflib.plugin.parser
+
+
+[options.entry_points]
+rdf.plugins.parser =
+    example.rdflib.plugin.parser = example.rdflib.plugin.parser:ExampleParser

test/plugins/parser/setup.py

@@ -0,0 +1,3 @@
+from setuptools import setup
+
+setup()

test/plugins/sparqleval/example/rdflib/plugin/sparqleval/__init__.py

@@ -0,0 +1,34 @@
+from typing import Any
+
+
+def custom_eval_extended(ctx: Any, extend: Any) -> Any:
+    for c in evalPart(ctx, extend.p):
+        try:
+            if hasattr(extend.expr, "iri") and extend.expr.iri == function_uri:
+                evaluation = function_result
+            else:
+                evaluation = _eval(extend.expr, c.forget(ctx, _except=extend._vars))
+                if isinstance(evaluation, SPARQLError):
+                    raise evaluation
+
+            yield c.merge({extend.var: evaluation})
+
+        except SPARQLError:
+            yield c
+
+
+def custom_eval(ctx: Any, part: Any) -> Any:
+    if part.name == "Extend":
+        return custom_eval_extended(ctx, part)
+    else:
+        raise NotImplementedError()
+
+
+from rdflib import Namespace
+from rdflib.plugins.sparql.evaluate import evalPart
+from rdflib.plugins.sparql.evalutils import _eval
+from rdflib.plugins.sparql.sparql import SPARQLError
+
+namespace = Namespace("example:rdflib:plugin:sparqleval:")
+function_uri = namespace["function"]
+function_result = namespace["result"]

test/plugins/sparqleval/setup.cfg

@@ -0,0 +1,17 @@
+# https://setuptools.pypa.io/en/latest/userguide/declarative_config.html
+# https://setuptools.pypa.io/en/latest/references/keywords.html
+[metadata]
+name = example.rdflib.plugin.sparqleval
+version = 0.0.0
+
+[options]
+packages = find_namespace:
+
+[options.packages.find]
+include =
+    example.rdflib.plugin.sparqleval
+
+
+[options.entry_points]
+rdf.plugins.sparqleval =
+    example.rdflib.plugin.sparqleval = example.rdflib.plugin.sparqleval:custom_eval

test/plugins/sparqleval/setup.py

@@ -0,0 +1,3 @@
+from setuptools import setup
+
+setup()

test/test_plugins.py

@@ -0,0 +1,127 @@
+import importlib
+import logging
+import shutil
+import subprocess
+import sys
+from contextlib import ExitStack, contextmanager
+from pathlib import Path
+from typing import Any, Callable, Dict, Generator, List
+
+from sphinx import warnings
+
+import rdflib.plugin
+import rdflib.plugins.sparql
+import rdflib.plugins.sparql.evaluate
+from rdflib import Graph
+from rdflib.parser import Parser
+
+TEST_DIR = Path(__file__).parent
+TEST_PLUGINS_DIR = TEST_DIR / "plugins"
+
+
+def del_key(d: Dict[Any, Any], key: Any) -> None:
+    del d[key]
+
+
+@contextmanager
+def ctx_plugin(tmp_path: Path, plugin_src: Path) -> Generator[None, None, None]:
+    base = tmp_path / f"{hash(plugin_src)}"
+    pypath = (base / "pypath").absolute()
+    plugpath = (base / "plugin").absolute()
+    shutil.copytree(plugin_src, plugpath)
+    logging.debug("Installing %s into %s", plugin_src, pypath)
+    subprocess.run(
+        [
+            sys.executable,
+            "-m",
+            "pip",
+            "install",
+            "--isolated",
+            "--no-input",
+            "--no-clean",
+            "--no-index",
+            "--disable-pip-version-check",
+            "--target",
+            f"{pypath}",
+            f"{plugpath}",
+        ],
+        check=True,
+    )
+
+    sys.path.append(f"{pypath}")
+
+    yield None
+
+    sys.path.remove(f"{pypath}")
+
+
+@contextmanager
+def ctx_cleaners() -> Generator[List[Callable[[], None]], None, None]:
+    cleaners: List[Callable[[], None]] = []
+    yield cleaners
+    for cleaner in cleaners:
+        logging.debug("running cleaner %s", cleaner)
+        cleaner()
+
+
+# Using no_cover as coverage freaks out and crashes because of what is happening here.
+def test_sparqleval(tmp_path: Path, no_cover: None) -> None:
+    with ExitStack() as stack:
+        stack.enter_context(ctx_plugin(tmp_path, TEST_PLUGINS_DIR / "sparqleval"))
+        warnings_record = stack.enter_context(warnings.catch_warnings(record=True))
+        cleaners = stack.enter_context(ctx_cleaners())
+
+        ep_name = "example.rdflib.plugin.sparqleval"
+        ep_ns = f'{ep_name.replace(".", ":")}:'
+        plugin_module = importlib.import_module(ep_name)
+        assert plugin_module.namespace == ep_ns
+
+        importlib.reload(rdflib.plugins.sparql)
+        importlib.reload(rdflib.plugins.sparql.evaluate)
+
+        cleaners.insert(0, lambda: del_key(rdflib.plugins.sparql.CUSTOM_EVALS, ep_name))
+
+        logging.debug(
+            "rdflib.plugins.sparql.CUSTOM_EVALS = %s",
+            rdflib.plugins.sparql.CUSTOM_EVALS,
+        )
+
+        graph = Graph()
+        query_string = (
+            "SELECT ?output1 WHERE { BIND(<" + ep_ns + "function>() AS ?output1) }"
+        )
+        logging.debug("query_string = %s", query_string)
+        result = graph.query(query_string)
+        assert result.type == "SELECT"
+        rows = list(result)
+        logging.debug("rows = %s", rows)
+        assert len(rows) == 1
+        assert len(rows[0]) == 1
+        assert rows[0][0] == plugin_module.function_result
+        assert [str(msg) for msg in warnings_record] == []
+
+
+# Using no_cover as coverage freaks out and crashes because of what is happening here.
+def test_parser(tmp_path: Path, no_cover: None) -> None:
+    with ExitStack() as stack:
+        stack.enter_context(ctx_plugin(tmp_path, TEST_PLUGINS_DIR / "parser"))
+        warnings_record = stack.enter_context(warnings.catch_warnings(record=True))
+        cleaners = stack.enter_context(ctx_cleaners())
+
+        ep_name = "example.rdflib.plugin.parser"
+        ep_ns = f'{ep_name.replace(".", ":")}:'
+        plugin_module = importlib.import_module(ep_name)
+        assert plugin_module.ExampleParser.namespace() == ep_ns
+
+        importlib.reload(rdflib.plugin)
+        cleaners.insert(0, lambda: del_key(rdflib.plugin._plugins, (ep_name, Parser)))
+
+        graph = Graph()
+        assert len(graph) == 0
+        graph.parse(format=ep_name, data="")
+
+        assert len(graph) > 0
+        triples = set(graph.triples((None, None, None)))
+        logging.debug("triples = %s", triples)
+        assert triples == plugin_module.ExampleParser.constant_output()
+        assert [str(msg) for msg in warnings_record] == []