improvement: remove dependency on pkg_resources directly in the mod…

…ule, although a transitive dependency (`nr.util.plugin`) still uses it

.changelog/_unreleased.toml

@@ -14,3 +14,12 @@ pr = "https://github.com/NiklasRosenstein/slap/pull/103"
 issues = [
     "https://github.com/NiklasRosenstein/slap/issues/102",
 ]
+
+[[entries]]
+id = "d8af87d8-191f-40e8-8099-e5a5618cf230"
+type = "improvement"
+description = "remove dependency on `pkg_resources` directly in the module, although a transitive dependency (`nr.util.plugin`) still uses it"
+author = "@NiklasRosenstein"
+issues = [
+    "https://github.com/NiklasRosenstein/slap/issues/98",
+]

docs/content/commands/add.md

@@ -23,13 +23,14 @@ Poetry as the build backend, it will add `httpx = "^0.22.0"` wheras if it is usi
 
 !!! note
 
-    Slap uses `pkg_resources.get_distribution()` to retrieve the version of the package that got installed, or was
-    already installed, and assumes that the package is available in the target Python environment.
+    Slap uses `importlib.metadata.distribution()` to retrieve the version of the package that got installed, or was
+    already installed, and assumes that the module is available in the target Python environment. The module is part
+    of the Python standard library starting with Python 3.8.
 
 ## Support matrix
 
-| Build system | Supported |
-| ------------ | --------- |
-| Flit | ✅ |
-| Poetry | ✅ |
-| Setuptools | ❌ (dependencies defined in `setup.cfg`) |
+| Build system | Supported                               |
+|--------------|-----------------------------------------|
+| Flit         | ✅                                       |
+| Poetry       | ✅                                       |
+| Setuptools   | ❌ (dependencies defined in `setup.cfg`) |

pyproject.toml

@@ -32,7 +32,7 @@ ptyprocess = "^0.7.0"
 pygments = "^2.11.2"
 PyYAML = ">=6.0"
 requests = "^2.27.1"
-setuptools = ">=39.1.0"  # Needed for pkg_resources
+setuptools = ">=39.1.0"  # Needed for setuptools backend
 tomli = "^2.0.0"
 tomlkit = "^0.12.1"
 twine = "^3.7.0"

src/slap/ext/application/report.py

@@ -3,8 +3,7 @@
 import json
 import logging
 import typing as t
-
-import pkg_resources
+from importlib.metadata import Distribution
 
 from slap.application import Application, option
 from slap.ext.application.venv import VenvAwareCommand
@@ -50,7 +49,7 @@ def handle(self) -> int:
             for extra in extras:
                 requirements += project.dependencies().extra.get(extra, [])
 
-        dists_cache: dict[str, pkg_resources.Distribution | None] = {}
+        dists_cache: dict[str, Distribution | None] = {}
         python_environment = PythonEnvironment.of("python")
         requirements = filter_dependencies(requirements, python_environment.pep508, extras)
         with tqdm.tqdm(desc="Resolving requirements graph") as progress:
@@ -67,15 +66,16 @@ def handle(self) -> int:
         # Retrieve the license text from the distributions.
         if self.option("with-license-text"):
             for dist_name, dist_data in output["metadata"].items():
-                dist = dists_cache[dist_name]
+                if (dist := dists_cache[dist_name]) is None:
+                    continue
+
                 dist_data["license_text"] = None
-                if dist is not None:
-                    for filename in ("LICENSE", "LICENSE.txt", "LICENSE.text", "LICENSE.rst"):
-                        try:
-                            dist_data["license_text"] = dist.get_metadata(filename)
-                            break
-                        except FileNotFoundError:
-                            pass
+                for file in dist.files or []:
+                    if not file.parent.name.endswith(".dist-info"):
+                        continue
+                    if file.name == "LICENSE" or file.name.startswith("LICENSE."):
+                        dist_data["license_text"] = file.read_text()
+                        break
 
         print(json.dumps(output, indent=2, sort_keys=True))
         return 0

src/slap/python/environment.py

@@ -9,12 +9,13 @@
 import subprocess as sp
 import textwrap
 import typing as t
+from importlib.metadata import PathDistribution
 from pathlib import Path
 
 from slap.python import pep508
 
 if t.TYPE_CHECKING:
-    import pkg_resources
+    from importlib.metadata import Distribution
 
     from slap.python.dependency import Dependency
 
@@ -40,13 +41,13 @@ def is_venv(self) -> bool:
 
         return bool(self.real_prefix or (self.base_prefix and self.prefix != self.base_prefix))
 
-    def has_pkg_resources(self) -> bool:
-        """Checks if the Python environment has the `pkg_resources` module available."""
+    def has_importlib_metadata(self) -> bool:
+        """Checks if the Python environment has the `importlib.metadata` module available."""
 
         if self._has_pkg_resources is None:
             code = textwrap.dedent(
                 """
-        try: import pkg_resources
+        try: import importlib.metadata
         except ImportError: print('false')
         else: print('true')
       """
@@ -79,8 +80,8 @@ def of(python: str | t.Sequence[str]) -> "PythonEnvironment":
       import sys, platform, json, pickle
       sys.path.append({pep508_path!r})
       import pep508
-      try: import pkg_resources
-      except ImportError: pkg_resources = None
+      try: import importlib.metadata as metadata
+      except ImportError: metadata = None
       print(json.dumps({{
         "executable": sys.executable,
         "version": sys.version,
@@ -90,7 +91,7 @@ def of(python: str | t.Sequence[str]) -> "PythonEnvironment":
         "base_prefix": getattr(sys, 'base_prefix', None),
         "real_prefix": getattr(sys, 'real_prefix', None),
         "pep508": pep508.Pep508Environment.current().as_json(),
-        "_has_pkg_resources": pkg_resources is not None,
+        "_has_pkg_resources": metadata is not None,
       }}))
     """
         )
@@ -100,25 +101,25 @@ def of(python: str | t.Sequence[str]) -> "PythonEnvironment":
         payload["pep508"] = pep508.Pep508Environment(**payload["pep508"])
         return PythonEnvironment(**payload)
 
-    def get_distribution(self, distribution: str) -> pkg_resources.Distribution | None:
+    def get_distribution(self, distribution: str) -> Distribution | None:
         """Query the details for a single distribution in the Python environment."""
 
         return self.get_distributions([distribution])[distribution]
 
-    def get_distributions(self, distributions: t.Collection[str]) -> dict[str, pkg_resources.Distribution | None]:
+    def get_distributions(self, distributions: t.Collection[str]) -> dict[str, Distribution | None]:
         """Query the details for the given distributions in the Python environment with
-        #pkg_resources.get_distribution()."""
+        #importlib.metadata.distribution()."""
 
         code = textwrap.dedent(
             """
-      import sys, pkg_resources, pickle
+      import sys, importlib.metadata as metadata, pickle
       result = []
       for arg in sys.argv[1:]:
         try:
-          dist = pkg_resources.get_distribution(arg)
-        except pkg_resources.DistributionNotFound:
+          dist = metadata.distribution(arg)
+        except metadata.PackageNotFoundError:
           dist = None
-        result.append(dist  )
+        result.append(dist)
       sys.stdout.buffer.write(pickle.dumps(result))
     """
         )
@@ -132,7 +133,7 @@ def get_distributions(self, distributions: t.Collection[str]) -> dict[str, pkg_r
 class DistributionMetadata:
     """Additional metadata for a distribution."""
 
-    location: str
+    location: str | None
     version: str
     license_name: str | None
     platform: str | None
@@ -141,21 +142,17 @@ class DistributionMetadata:
     extras: set[str]
 
 
-def get_distribution_metadata(dist: pkg_resources.Distribution) -> DistributionMetadata:
+def get_distribution_metadata(dist: Distribution) -> DistributionMetadata:
     """Parses the distribution metadata."""
 
-    from email.parser import Parser
-
-    data = Parser().parsestr(dist.get_metadata(dist.PKG_INFO))
-
     return DistributionMetadata(
-        location=dist.location,
-        version=data.get("Version"),
-        license_name=data.get("License"),
-        platform=data.get("Platform"),
-        requires_python=data.get("Requires-Python"),
-        requirements=data.get_all("Requires-Dist") or [],
-        extras=set(data.get_all("Provides-Extra") or []),
+        location=str(dist._path) if isinstance(dist, PathDistribution) else None,  # type: ignore[attr-defined]
+        version=dist.metadata["Version"],
+        license_name=dist.metadata.get("License"),
+        platform=dist.metadata.get("Platform"),
+        requires_python=dist.metadata.get("Requires-Python"),
+        requirements=dist.metadata.get_all("Requires-Dist") or [],
+        extras=set(dist.metadata.get_all("Provides-Extra") or []),
     )
 
 
@@ -187,8 +184,8 @@ def update(self, other: DistributionGraph) -> None:
 def build_distribution_graph(
     env: PythonEnvironment,
     dependencies: list[Dependency],
-    resolved_callback: t.Callable[[dict[str, pkg_resources.Distribution | None]], t.Any] | None = None,
-    dists_cache: dict[str, pkg_resources.Distribution | None] | None = None,
+    resolved_callback: t.Callable[[dict[str, Distribution | None]], t.Any] | None = None,
+    dists_cache: dict[str, Distribution | None] | None = None,
 ) -> DistributionGraph:
     """Builds a #DistributionGraph in the given #PythonEnvironment using the given dependencies.
 

src/slap/templates/github/.github/workflows/python.yaml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.x"]
+        python-version: ["3.8", "3.9", "3.10", "3.11"]
     steps:
     - uses: actions/checkout@v2
     - uses: NiklasRosenstein/slap@gha/install/v1

tests/slap/python/test_environment.py

@@ -12,5 +12,5 @@ def test__PythonEnvironment__with_current_python_instance():
     assert environment.prefix == sys.prefix
     assert environment.base_prefix == getattr(sys, "base_prefix", None)
     assert environment.real_prefix == getattr(sys, "real_prefix", None)
-    assert environment.has_pkg_resources()  # Slap requires setuptools, so pkg_resources is definitely available
+    assert environment.has_importlib_metadata()
     assert environment.get_distribution("setuptools") is not None