Use importlib_metadata rather than pip freeze

macros.pyproject

@@ -24,7 +24,6 @@ fi
 %{-e:%{expand:%global toxenv %{-e*}}}
 echo 'python3-devel'
 echo 'python3dist(packaging)'
-echo 'python3dist(pip) >= 19'
 echo 'python3dist(pytoml)'
 # setuptools assumes no pre-existing dist-info
 rm -rfv *.dist-info/

pyproject-rpm-macros.spec

@@ -21,17 +21,28 @@ URL:            https://src.fedoraproject.org/rpms/pyproject-rpm-macros
 
 BuildArch:      noarch
 
-# We keep them here for now to avoid one loop of %%generate_buildrequires
-# And to allow the other macros without %%pyproject_buildrequires (e.g. on Fedora 30)
-# But those are also always in the output of %%generate_buildrequires
-# in order to be removable in the future
 Requires: python3-pip >= 19
 Requires: python3-devel
 
+# We keep these here for now to avoid one loop of %%generate_buildrequires
+# But those are also always in the output of %%generate_buildrequires
+# in order to be removable in the future
+Requires: python3dist(packaging)
+Requires: python3dist(pytoml)
+
+# This is not output from %%generate_buildrequires to work around:
+#   https://github.com/rpm-software-management/mock/issues/336
+Requires: (python3dist(importlib-metadata) if python3 < 3.8)
+
 %if %{with tests}
 BuildRequires: python3dist(pytest)
 BuildRequires: python3dist(pyyaml)
 BuildRequires: python3dist(packaging)
+%if 0%{fedora} < 32
+# The %%if should not be needed, it works around:
+#   https://github.com/rpm-software-management/mock/issues/336
+BuildRequires: (python3dist(importlib-metadata) if python3 < 3.8)
+%endif
 BuildRequires: python3dist(pytoml)
 BuildRequires: python3dist(pip)
 BuildRequires: python3dist(setuptools)

pyproject_buildrequires.py

@@ -26,7 +26,10 @@ try:
     from packaging.requirements import Requirement, InvalidRequirement
     from packaging.version import Version
     from packaging.utils import canonicalize_name, canonicalize_version
-    import pip
+    try:
+        import importlib.metadata as importlib_metadata
+    except ImportError:
+        import importlib_metadata
 except ImportError as e:
     print_err('Import error:', e)
     # already echoed by the %pyproject_buildrequires macro
@@ -44,14 +47,8 @@ def hook_call():
 
 class Requirements:
     """Requirement printer"""
-    def __init__(self, freeze_output, extras=''):
+    def __init__(self, get_installed_version, extras=''):
-        self.installed_packages = {}
+        self.get_installed_version = get_installed_version
-        for line in freeze_output.splitlines():
-            line = line.strip()
-            if line.startswith('#'):
-                continue
-            name, version = line.split('==')
-            self.installed_packages[name.strip()] = Version(version)
 
         self.marker_env = {'extra': extras}
 
@@ -77,7 +74,11 @@ class Requirements:
             print_err(f'Ignoring alien requirement:', requirement_str)
             return
 
-        installed = self.installed_packages.get(requirement.name)
+        try:
+            installed = self.get_installed_version(requirement.name)
+        except importlib_metadata.PackageNotFoundError:
+            print_err(f'Requirement not satisfied: {requirement_str}')
+            installed = None
         if installed and installed in requirement.specifier:
             print_err(f'Requirement satisfied: {requirement_str}')
             print_err(f'   (installed: {requirement.name} {installed})')
@@ -203,9 +204,14 @@ def python3dist(name, op=None, version=None):
 
 
 def generate_requires(
-    freeze_output, *, include_runtime=False, toxenv=None, extras='',
+    *, include_runtime=False, toxenv=None, extras='',
+    get_installed_version=importlib_metadata.version,  # for dep injection
 ):
-    requirements = Requirements(freeze_output, extras=extras)
+    """Generate the BuildRequires for the project in the current directory
+
+    This is the main Python entry point.
+    """
+    requirements = Requirements(get_installed_version, extras=extras)
 
     try:
         backend = get_backend(requirements)
@@ -259,16 +265,8 @@ def main(argv):
         print_err('-x (--extras) are only useful with -r (--runtime)')
         exit(1)
 
-    freeze_output = subprocess.run(
-        [sys.executable, '-I', '-m', 'pip', 'freeze', '--all'],
-        encoding='utf-8',
-        stdout=subprocess.PIPE,
-        check=True,
-    ).stdout
-
     try:
         generate_requires(
-            freeze_output,
             include_runtime=args.runtime,
             toxenv=args.toxenv,
             extras=args.extras,

test_pyproject_buildrequires.py

@@ -6,6 +6,11 @@ import yaml
 
 from pyproject_buildrequires import generate_requires
 
+try:
+    import importlib.metadata as importlib_metadata
+except ImportError:
+    import importlib_metadata
+
 testcases = {}
 with Path(__file__).parent.joinpath('testcases.yaml').open() as f:
     testcases = yaml.safe_load(f)
@@ -26,9 +31,17 @@ def test_data(case_name, capsys, tmp_path, monkeypatch):
         if filename in case:
             cwd.joinpath(filename).write_text(case[filename])
 
+    def get_installed_version(dist_name):
+        try:
+            return str(case['installed'][dist_name])
+        except (KeyError, TypeError):
+            raise importlib_metadata.PackageNotFoundError(
+                f'info not found for {dist_name}'
+            )
+
     try:
         generate_requires(
-            case['freeze_output'],
+            get_installed_version=get_installed_version,
             include_runtime=case.get('include_runtime', False),
             extras=case.get('extras', ''),
             toxenv=case.get('toxenv', None),

testcases.yaml

@@ -1,5 +1,5 @@
 No pyproject.toml, nothing installed:
-  freeze_output: |
+  installed:
     # empty
   expected: |
     python3dist(setuptools) >= 40.8
@@ -7,7 +7,7 @@ No pyproject.toml, nothing installed:
   result: 0
 
 Nothing installed yet:
-  freeze_output: |
+  installed:
     # empty
   pyproject.toml: |
     # empty
@@ -17,9 +17,9 @@ Nothing installed yet:
   result: 0
 
 Insufficient version of setuptools:
-  freeze_output: |
+  installed:
-    setuptools==5
+    setuptools: 5
-    wheel==1
+    wheel: 1
   pyproject.toml: |
     # empty
   expected: |
@@ -28,9 +28,9 @@ Insufficient version of setuptools:
   result: 0
 
 Empty pyproject.toml, empty setup.py:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
   setup.py: |
   expected: |
     python3dist(setuptools) >= 40.8
@@ -39,9 +39,9 @@ Empty pyproject.toml, empty setup.py:
   result: 0
 
 Default build system, empty setup.py:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
   pyproject.toml: |
     # empty
   setup.py: |
@@ -52,24 +52,24 @@ Default build system, empty setup.py:
   result: 0
 
 Erroring setup.py:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
   setup.py: |
     exit(77)
   result: 77
 
 Bad character in version:
-  freeze_output: |
+  installed: {}
   pyproject.toml: |
     [build-system]
     requires = ["pkg == 0.$.^.*"]
   except: ValueError
 
 Build system dependencies in pyproject.toml:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
   pyproject.toml: |
     [build-system]
     requires = [
@@ -100,9 +100,9 @@ Build system dependencies in pyproject.toml:
   result: 0
 
 Default build system, build dependencies in setup.py:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
   setup.py: |
     from setuptools import setup
     setup(
@@ -120,10 +120,10 @@ Default build system, build dependencies in setup.py:
   result: 0
 
 Default build system, run dependencies in setup.py:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
-    pyyaml==1
+    pyyaml: 1
   include_runtime: true
   setup.py: |
     from setuptools import setup
@@ -143,10 +143,10 @@ Default build system, run dependencies in setup.py:
   result: 0
 
 Run dependencies with extras (not selected):
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
-    pyyaml==1
+    pyyaml: 1
   include_runtime: true
   setup.py: &pytest_setup_py |
         # slightly abriged copy of pytest's setup.py
@@ -200,10 +200,10 @@ Run dependencies with extras (not selected):
   result: 0
 
 Run dependencies with extras (selected):
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
-    pyyaml==1
+    pyyaml: 1
   include_runtime: true
   extras: testing
   setup.py: *pytest_setup_py
@@ -227,10 +227,10 @@ Run dependencies with extras (selected):
 
 Run dependencies with multiple extras:
   xfail: requirement.marker.evaluate seems to not support multiple extras
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
-    pyyaml==1
+    pyyaml: 1
   include_runtime: true
   extras: testing,more-testing, even-more-testing , cool-feature
   setup.py: |
@@ -246,19 +246,18 @@ Run dependencies with multiple extras:
   expected: |
     python3dist(setuptools) >= 40.8
     python3dist(wheel)
-    python3dist(wheel)
     python3dist(dep1)
     python3dist(dep2)
     python3dist(dep3)
     python3dist(dep4)
   result: 0
 
-Tox depndencies:
+Tox dependencies:
-  freeze_output: |
+  installed:
-    setuptools==50
+    setuptools: 50
-    wheel==1
+    wheel: 1
-    tox==3.5.3
+    tox: 3.5.3
-    tox-current-env==0.0.2
+    tox-current-env: 0.0.2
   toxenv: py3
   setup.py: |
     from setuptools import setup