Abort install if Requires-Python do not match the running version

CHANGES.txt

@@ -52,6 +52,9 @@
 
 * Normalize package names before using in ``pip show`` (:issue:`3976`)
 
+* Raises when Requires-Python do not match the running version.
+  Add ``--ignore-requires-python`` escape hatch.
+
 
 **8.1.2 (2016-05-10)**
 

pip/cmdoptions.py

@@ -477,6 +477,13 @@ def only_binary():
     help='Directory to unpack packages into and build in.'
 )
 
+ignore_requires_python = partial(
+    Option,
+    '--ignore-requires-python',
+    dest='ignore_requires_python',
+    action='store_true',
+    help='Ignore the Requires-Python information.')
+
 install_options = partial(
     Option,
     '--install-option',

pip/commands/install.py

@@ -118,6 +118,7 @@ def __init__(self, *args, **kw):
             action='store_true',
             help='Ignore the installed packages (reinstalling instead).')
 
+        cmd_opts.add_option(cmdoptions.ignore_requires_python())
         cmd_opts.add_option(cmdoptions.no_deps())
 
         cmd_opts.add_option(cmdoptions.install_options())
@@ -295,6 +296,7 @@ def run(self, options, args):
                     as_egg=options.as_egg,
                     ignore_installed=options.ignore_installed,
                     ignore_dependencies=options.ignore_dependencies,
+                    ignore_requires_python=options.ignore_requires_python,
                     force_reinstall=options.force_reinstall,
                     use_user_site=options.use_user_site,
                     target_dir=temp_target_dir,

pip/commands/wheel.py

@@ -70,6 +70,7 @@ def __init__(self, *args, **kw):
         cmd_opts.add_option(cmdoptions.editable())
         cmd_opts.add_option(cmdoptions.requirements())
         cmd_opts.add_option(cmdoptions.src())
+        cmd_opts.add_option(cmdoptions.ignore_requires_python())
         cmd_opts.add_option(cmdoptions.no_deps())
         cmd_opts.add_option(cmdoptions.build_dir())
 
@@ -171,6 +172,7 @@ def run(self, options, args):
                     download_dir=None,
                     ignore_dependencies=options.ignore_dependencies,
                     ignore_installed=True,
+                    ignore_requires_python=options.ignore_requires_python,
                     isolated=options.isolated_mode,
                     session=session,
                     wheel_cache=wheel_cache,

pip/exceptions.py

@@ -237,3 +237,8 @@ def hash_then_or(hash_name):
                          self.gots[hash_name].hexdigest())
             prefix = '    or'
         return '\n'.join(lines)
+
+
+class UnsupportedPythonVersion(InstallationError):
+    """Unsupported python version according to Requires-Python package
+    metadata."""

pip/req/req_set.py

@@ -14,12 +14,14 @@
 from pip.exceptions import (InstallationError, BestVersionAlreadyInstalled,
                             DistributionNotFound, PreviousBuildDirError,
                             HashError, HashErrors, HashUnpinned,
-                            DirectoryUrlHashUnsupported, VcsHashUnsupported)
+                            DirectoryUrlHashUnsupported, VcsHashUnsupported,
+                            UnsupportedPythonVersion)
 from pip.req.req_install import InstallRequirement
 from pip.utils import (
     display_path, dist_in_usersite, ensure_dir, normalize_path)
 from pip.utils.hashes import MissingHashes
 from pip.utils.logging import indent_log
+from pip.utils.packaging import check_dist_requires_python
 from pip.vcs import vcs
 from pip.wheel import Wheel
 
@@ -144,7 +146,8 @@ def __init__(self, build_dir, src_dir, download_dir, upgrade=False,
                  target_dir=None, ignore_dependencies=False,
                  force_reinstall=False, use_user_site=False, session=None,
                  pycompile=True, isolated=False, wheel_download_dir=None,
-                 wheel_cache=None, require_hashes=False):
+                 wheel_cache=None, require_hashes=False,
+                 ignore_requires_python=False):
         """Create a RequirementSet.
 
         :param wheel_download_dir: Where still-packed .whl files should be
@@ -178,6 +181,7 @@ def __init__(self, build_dir, src_dir, download_dir, upgrade=False,
         self.requirement_aliases = {}
         self.unnamed_requirements = []
         self.ignore_dependencies = ignore_dependencies
+        self.ignore_requires_python = ignore_requires_python
         self.successfully_downloaded = []
         self.successfully_installed = []
         self.reqs_to_cleanup = []
@@ -655,6 +659,14 @@ def _prepare_file(self,
             # # parse dependencies # #
             # ###################### #
             dist = abstract_dist.dist(finder)
+            try:
+                check_dist_requires_python(dist)
+            except UnsupportedPythonVersion as e:
+                if self.ignore_requires_python:
+                    logger.warning(e.args[0])
+                else:
+                    req_to_install.remove_temporary_source()
+                    raise
             more_reqs = []
 
             def add_req(subreq):

pip/utils/packaging.py

@@ -1,9 +1,15 @@
 from __future__ import absolute_import
+
+from email.parser import FeedParser
+
 import logging
 import sys
 
 from pip._vendor.packaging import specifiers
 from pip._vendor.packaging import version
+from pip._vendor import pkg_resources
+
+from pip import exceptions
 
 logger = logging.getLogger(__name__)
 
@@ -26,3 +32,32 @@ def check_requires_python(requires_python):
     # We only use major.minor.micro
     python_version = version.parse('.'.join(map(str, sys.version_info[:3])))
     return python_version in requires_python_specifier
+
+
+def get_metadata(dist):
+    if (isinstance(dist, pkg_resources.DistInfoDistribution) and
+            dist.has_metadata('METADATA')):
+        return dist.get_metadata('METADATA')
+    elif dist.has_metadata('PKG-INFO'):
+        return dist.get_metadata('PKG-INFO')
+
+
+def check_dist_requires_python(dist):
+    metadata = get_metadata(dist)
+    feed_parser = FeedParser()
+    feed_parser.feed(metadata)
+    pkg_info_dict = feed_parser.close()
+    requires_python = pkg_info_dict.get('Requires-Python')
+    try:
+        if not check_requires_python(requires_python):
+            raise exceptions.UnsupportedPythonVersion(
+                "%s requires Python '%s' but the running Python is %s" % (
+                    dist.project_name,
+                    requires_python,
+                    '.'.join(map(str, sys.version_info[:3])),)
+            )
+    except specifiers.InvalidSpecifier as e:
+        logger.warning(
+            "Package %s has an invalid Requires-Python entry %s - %s" % (
+                dist.project_name, requires_python, e))
+        return

tests/functional/test_install.py

@@ -1076,3 +1076,67 @@ def test_double_install_fail(script, data):
     msg = ("Double requirement given: pip==7.1.2 (already in pip==*, "
            "name='pip')")
     assert msg in result.stderr
+
+
+def test_install_incompatible_python_requires(script):
+    script.scratch_path.join("pkga").mkdir()
+    pkga_path = script.scratch_path / 'pkga'
+    pkga_path.join("setup.py").write(textwrap.dedent("""
+        from setuptools import setup
+        setup(name='pkga',
+              python_requires='<1.0',
+              version='0.1')
+    """))
+    script.pip('install', 'setuptools>24.2')  # This should not be needed
+    result = script.pip('install', pkga_path, expect_error=True)
+    assert ("pkga requires Python '<1.0' "
+            "but the running Python is ") in result.stderr
+
+
+def test_install_incompatible_python_requires_editable(script):
+    script.scratch_path.join("pkga").mkdir()
+    pkga_path = script.scratch_path / 'pkga'
+    pkga_path.join("setup.py").write(textwrap.dedent("""
+        from setuptools import setup
+        setup(name='pkga',
+              python_requires='<1.0',
+              version='0.1')
+    """))
+    script.pip('install', 'setuptools>24.2')  # This should not be needed
+    result = script.pip(
+        'install', '--editable=%s' % pkga_path, expect_error=True)
+    assert ("pkga requires Python '<1.0' "
+            "but the running Python is ") in result.stderr
+
+
+def test_install_incompatible_python_requires_wheel(script):
+    script.scratch_path.join("pkga").mkdir()
+    pkga_path = script.scratch_path / 'pkga'
+    pkga_path.join("setup.py").write(textwrap.dedent("""
+        from setuptools import setup
+        setup(name='pkga',
+              python_requires='<1.0',
+              version='0.1')
+    """))
+    script.pip('install', 'setuptools>24.2')  # This should not be needed
+    script.pip('install', 'wheel')
+    script.run(
+        'python', 'setup.py', 'bdist_wheel', '--universal', cwd=pkga_path)
+    result = script.pip('install', './pkga/dist/pkga-0.1-py2.py3-none-any.whl',
+                        expect_error=True)
+    assert ("pkga requires Python '<1.0' "
+            "but the running Python is ") in result.stderr
+
+
+def test_install_compatible_python_requires(script):
+    script.scratch_path.join("pkga").mkdir()
+    pkga_path = script.scratch_path / 'pkga'
+    pkga_path.join("setup.py").write(textwrap.dedent("""
+        from setuptools import setup
+        setup(name='pkga',
+              python_requires='>1.0',
+              version='0.1')
+    """))
+    script.pip('install', 'setuptools>24.2')  # This should not be needed
+    res = script.pip('install', pkga_path, expect_error=True)
+    assert "Successfully installed pkga-0.1" in res.stdout, res

tests/unit/test_utils.py

@@ -15,13 +15,15 @@
 import pytest
 
 from mock import Mock, patch
-from pip.exceptions import HashMismatch, HashMissing, InstallationError
+from pip.exceptions import (HashMismatch, HashMissing, InstallationError,
+                            UnsupportedPythonVersion)
 from pip.utils import (egg_link_path, get_installed_distributions,
                        untar_file, unzip_file, rmtree, normalize_path)
 from pip.utils.build import BuildDirectory
 from pip.utils.encoding import auto_decode
 from pip.utils.hashes import Hashes, MissingHashes
 from pip.utils.glibc import check_glibc_version
+from pip.utils.packaging import check_dist_requires_python
 from pip._vendor.six import BytesIO
 
 
@@ -524,3 +526,25 @@ def test_manylinux1_check_glibc_version(self):
                 else:
                     # Didn't find the warning we were expecting
                     assert False
+
+
+class TestCheckRequiresPython(object):
+
+    @pytest.mark.parametrize(
+        ("metadata", "should_raise"),
+        [
+            ("Name: test\n", False),
+            ("Name: test\nRequires-Python:", False),
+            ("Name: test\nRequires-Python: invalid_spec", False),
+            ("Name: test\nRequires-Python: <=1", True),
+        ],
+    )
+    def test_check_requires(self, metadata, should_raise):
+        fake_dist = Mock(
+            has_metadata=lambda _: True,
+            get_metadata=lambda _: metadata)
+        if should_raise:
+            with pytest.raises(UnsupportedPythonVersion):
+                check_dist_requires_python(fake_dist)
+        else:
+            check_dist_requires_python(fake_dist)