python3.pkgs.pythonRuntimeDepsCheckHook: init

Implements a hook, that checks whether all dependencies, as specified by
the wheel manifest, are present in the current environment.

Complains about missing packages, as well as version specifier
mismatches.

pkgs/development/interpreters/python/hooks/default.nix

···
       };
     } ./python-remove-tests-dir-hook.sh) {};
 
+  pythonRuntimeDepsCheckHook = callPackage ({ makePythonHook, packaging }:
+    makePythonHook {
+      name = "python-runtime-deps-check-hook.sh";
+      propagatedBuildInputs = [ packaging ];
+      substitutions = {
+        inherit pythonInterpreter pythonSitePackages;
+        hook = ./python-runtime-deps-check-hook.py;
+      };
+    } ./python-runtime-deps-check-hook.sh) {};
+
   setuptoolsBuildHook = callPackage ({ makePythonHook, setuptools, wheel }:
     makePythonHook {
       name = "setuptools-setup-hook";

pkgs/development/interpreters/python/hooks/python-runtime-deps-check-hook.py

···
+#!/usr/bin/env python3
+"""
+The runtimeDependenciesHook validates, that all dependencies specified
+in wheel metadata are available in the local environment.
+
+In case that does not hold, it will print missing dependencies and
+violated version constraints.
+"""
+
+
+import importlib.metadata
+import re
+import sys
+import tempfile
+from argparse import ArgumentParser
+from zipfile import ZipFile
+
+from packaging.metadata import Metadata, parse_email
+from packaging.requirements import Requirement
+
+argparser = ArgumentParser()
+argparser.add_argument("wheel", help="Path to the .whl file to test")
+
+
+def error(msg: str) -> None:
+    print(f"  - {msg}", file=sys.stderr)
+
+
+def normalize_name(name: str) -> str:
+    """
+    Normalize package names according to PEP503
+    """
+    return re.sub(r"[-_.]+", "-", name).lower()
+
+
+def get_manifest_text_from_wheel(wheel: str) -> str:
+    """
+    Given a path to a wheel, this function will try to extract the
+    METADATA file in the wheels .dist-info directory.
+    """
+    with ZipFile(wheel) as zipfile:
+        for zipinfo in zipfile.infolist():
+            if zipinfo.filename.endswith(".dist-info/METADATA"):
+                with tempfile.TemporaryDirectory() as tmp:
+                    path = zipfile.extract(zipinfo, path=tmp)
+                    with open(path, encoding="utf-8") as fd:
+                        return fd.read()
+
+    raise RuntimeError("No METADATA file found in wheel")
+
+
+def get_metadata(wheel: str) -> Metadata:
+    """
+    Given a path to a wheel, returns a parsed Metadata object.
+    """
+    text = get_manifest_text_from_wheel(wheel)
+    raw, _ = parse_email(text)
+    metadata = Metadata.from_raw(raw)
+
+    return metadata
+
+
+def test_requirement(requirement: Requirement) -> bool:
+    """
+    Given a requirement specification, tests whether the dependency can
+    be resolved in the local environment, and whether it satisfies the
+    specified version constraints.
+    """
+    if requirement.marker and not requirement.marker.evaluate():
+        # ignore requirements with incompatible markers
+        return True
+
+    package_name = normalize_name(requirement.name)
+
+    try:
+        package = importlib.metadata.distribution(requirement.name)
+    except importlib.metadata.PackageNotFoundError:
+        error(f"{package_name} not installed")
+        return False
+
+    if package.version not in requirement.specifier:
+        error(
+            f"{package_name}{requirement.specifier} not satisfied by version {package.version}"
+        )
+        return False
+
+    return True
+
+
+if __name__ == "__main__":
+    args = argparser.parse_args()
+
+    metadata = get_metadata(args.wheel)
+    tests = [test_requirement(requirement) for requirement in metadata.requires_dist]
+
+    if not all(tests):
+        sys.exit(1)

pkgs/development/interpreters/python/hooks/python-runtime-deps-check-hook.sh

···
+# Setup hook for PyPA installer.
+echo "Sourcing python-runtime-deps-check-hook"
+
+pythonRuntimeDepsCheckHook() {
+    echo "Executing pythonRuntimeDepsCheck"
+
+    export PYTHONPATH="$out/@pythonSitePackages@:$PYTHONPATH"
+
+    for wheel in dist/*.whl; do
+        echo "Checking runtime dependencies for $(basename $wheel)"
+        @pythonInterpreter@ @hook@ "$wheel"
+    done
+
+    echo "Finished executing pythonRuntimeDepsCheck"
+}
+
+if [ -z "${dontCheckRuntimeDeps-}" ]; then
+    echo "Using pythonRuntimeDepsCheckHook"
+    preInstallPhases+=" pythonRuntimeDepsCheckHook"
+fi

pkgs/development/interpreters/python/mk-python-derivation.nix

···
 , pythonOutputDistHook
 , pythonRemoveBinBytecodeHook
 , pythonRemoveTestsDirHook
+, pythonRuntimeDepsCheckHook
 , setuptoolsBuildHook
 , setuptoolsCheckHook
 , wheelUnpackHook
···
         }
       else
         pypaBuildHook
+    ) (
+      if isBootstrapPackage then
+        pythonRuntimeDepsCheckHook.override {
+          inherit (python.pythonOnBuildForHost.pkgs.bootstrap) packaging;
+        }
+      else
+        pythonRuntimeDepsCheckHook
     )] ++ lib.optionals (format' == "wheel") [
       wheelUnpackHook
     ] ++ lib.optionals (format' == "egg") [

pkgs/development/python-modules/bootstrap/packaging/default.nix

···
+{ stdenv
+, python
+, flit-core
+, installer
+, packaging
+}:
+
+stdenv.mkDerivation {
+  pname = "${python.libPrefix}-bootstrap-${packaging.pname}";
+  inherit (packaging) version src meta;
+
+  buildPhase = ''
+    runHook preBuild
+
+    PYTHONPATH="${flit-core}/${python.sitePackages}" \
+      ${python.interpreter} -m flit_core.wheel
+
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    PYTHONPATH="${installer}/${python.sitePackages}" \
+      ${python.interpreter} -m installer \
+        --destdir "$out" --prefix "" dist/*.whl
+
+    runHook postInstall
+  '';
+}

pkgs/top-level/python-packages.nix

···
     build = toPythonModule (callPackage ../development/python-modules/bootstrap/build {
       inherit (bootstrap) flit-core installer;
     });
+    packaging = toPythonModule (callPackage ../development/python-modules/bootstrap/packaging {
+      inherit (bootstrap) flit-core installer;
+    });
   };
 
   setuptools = callPackage ../development/python-modules/setuptools { };