add validation rules for lower constraints

The requirement lower bound and lower-constraints.txt value must
match.

The lower-constraints.txt value must be compatible with the specified
range, including exclusions.

If there is no lower-constraints.txt file the additional tests are
skipped.

If no minimum is specified, the misconfiguration is left to the other
validation logic to catch.

Only files associated with test jobs are checked because other jobs
are not run with the lower constraints list.

Change-Id: Iefe3ef8a89e965537486a1c9a62ab887b4401530
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

openstack_requirements/check.py

@@ -19,6 +19,9 @@ import collections
 from openstack_requirements import project
 from openstack_requirements import requirement
 
+from packaging import markers
+from packaging import specifiers
+
 
 class RequirementsList(object):
     def __init__(self, name, project):
@@ -181,3 +184,125 @@ def validate(head_reqs, branch_reqs, blacklist, global_reqs):
             )
 
     return failed
+
+
+def _find_constraint(req, constraints):
+    """Return the constraint matching the markers for req.
+
+    Given a requirement, find the constraint with matching markers.
+    If none match, find a constraint without any markers at all.
+    Otherwise return None.
+    """
+    if req.markers:
+        req_markers = markers.Marker(req.markers)
+        for constraint_setting, _ in constraints:
+            if constraint_setting.markers == req.markers:
+                return constraint_setting
+            # NOTE(dhellmann): This is a very naive attempt to check
+            # marker compatibility that relies on internal
+            # implementation details of the packaging library.  The
+            # best way to ensure the constraint and requirements match
+            # is to use the same marker string in the corresponding
+            # lines.
+            c_markers = markers.Marker(constraint_setting.markers)
+            env = {
+                str(var): str(val)
+                for var, op, val in c_markers._markers  # WARNING: internals
+            }
+            if req_markers.evaluate(env):
+                return constraint_setting
+    # Try looking for a constraint without any markers.
+    for constraint_setting, _ in constraints:
+        if not constraint_setting.markers:
+            return constraint_setting
+    return None
+
+
+def validate_lower_constraints(req_list, constraints, blacklist):
+    """Return True if there is an error.
+
+    :param reqs: RequirementsList for the head of the branch
+    :param constraints: Parsed lower-constraints.txt or None
+
+    """
+    if constraints is None:
+        return False
+
+    parsed_constraints = requirement.parse(constraints)
+
+    failed = False
+
+    for fname, freqs in req_list.reqs_by_file.items():
+
+        if fname == 'doc/requirements.txt':
+            # Skip things that are not needed for unit or functional
+            # tests.
+            continue
+
+        print("Validating lower constraints of {}".format(fname))
+
+        for name, reqs in freqs.items():
+
+            if name in blacklist:
+                continue
+
+            if name not in parsed_constraints:
+                print('Package {!r} is used in {} '
+                      'but not in lower-constraints.txt'.format(
+                          name, fname))
+                failed = True
+                continue
+
+            for req in reqs:
+                spec = specifiers.SpecifierSet(req.specifiers)
+                # FIXME(dhellmann): This will only find constraints
+                # where the markers match the requirements list
+                # exactly, so we can't do things like use different
+                # constrained versions for different versions of
+                # python 3 if the requirement range is expressed as
+                # python_version>3.0. We can support different
+                # versions if there is a different requirement
+                # specification for each version of python. I don't
+                # really know how smart we want this to be, because
+                # I'm not sure we want to support extremely
+                # complicated dependency sets.
+                constraint_setting = _find_constraint(
+                    req,
+                    parsed_constraints[name],
+                )
+                if not constraint_setting:
+                    print('Unable to find constraint for {} '
+                          'matching {!r} or without any markers.'.format(
+                              name, req.markers))
+                    failed = True
+                    continue
+                print('req', req)
+                print('constraint_setting', constraint_setting)
+
+                version = constraint_setting.specifiers.lstrip('=')
+
+                if not spec.contains(version):
+                    print('Package {!r} is constrained to {} '
+                          'which is incompatible with the settings {} '
+                          'from {}.'.format(
+                              name, version, req, fname))
+                    failed = True
+
+                min = [
+                    s
+                    for s in req.specifiers.split(',')
+                    if '>' in s
+                ]
+                if not min:
+                    # No minimum specified. Ignore this and let some
+                    # other validation trap the error.
+                    continue
+
+                expected = min[0].lstrip('>=')
+                if version != expected:
+                    print('Package {!r} is constrained to {} '
+                          'which does not match '
+                          'the minimum version specifier {} in {}'.format(
+                              name, version, expected, fname))
+                    failed = True
+    return failed

openstack_requirements/project.py

@@ -132,13 +132,17 @@ def read(root):
     target_files = [
         'requirements.txt', 'tools/pip-requires',
         'test-requirements.txt', 'tools/test-requires',
-        'doc/requirements.txt'
+        'doc/requirements.txt',
     ]
     for py_version in (2, 3):
         target_files.append('requirements-py%s.txt' % py_version)
         target_files.append('test-requirements-py%s.txt' % py_version)
     for target_file in target_files:
         _safe_read(result, target_file, output=requirements)
+    # Read lower-constraints.txt and ensure the key is always present
+    # in case the file is missing.
+    result['lower-constraints.txt'] = None
+    _safe_read(result, 'lower-constraints.txt')
     return result
 
 

openstack_requirements/tests/test_check.py

@@ -396,3 +396,253 @@ class TestValidateOne(testtools.TestCase):
                 global_reqs=global_reqs,
             )
         )
+
+
+class TestValidateLowerConstraints(testtools.TestCase):
+
+    def setUp(self):
+        super(TestValidateLowerConstraints, self).setUp()
+        self._stdout_fixture = fixtures.StringStream('stdout')
+        self.stdout = self.useFixture(self._stdout_fixture).stream
+        self.useFixture(fixtures.MonkeyPatch('sys.stdout', self.stdout))
+
+    def test_no_constraints_file(self):
+        constraints_content = None
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.2,!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_no_min(self):
+        constraints_content = textwrap.dedent("""
+        name==1.2
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_matches(self):
+        constraints_content = textwrap.dedent("""
+        name==1.2
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.2,!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_not_constrained(self):
+        constraints_content = textwrap.dedent("""
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.2,!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertTrue(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_mismatch_blacklisted(self):
+        constraints_content = textwrap.dedent("""
+        name==1.2
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.3,!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse('name'),
+            )
+        )
+
+    def test_lower_bound_lower(self):
+        constraints_content = textwrap.dedent("""
+        name==1.2
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.1,!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertTrue(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_lower_bound_higher(self):
+        constraints_content = textwrap.dedent("""
+        name==1.2
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.3,!=1.4'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertTrue(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_constrained_version_excluded(self):
+        constraints_content = textwrap.dedent("""
+        name==1.2
+        """)
+        project_data = {
+            'requirements': {'requirements.txt': 'name>=1.1,!=1.2'},
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertTrue(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_constraints_with_markers(self):
+        constraints_content = textwrap.dedent("""
+        name==1.1;python_version=='2.7'
+        name==2.0;python_version=='3.5'
+        name==2.0;python_version=='3.6'
+        """)
+        project_data = {
+            'requirements': {
+                'requirements.txt': textwrap.dedent("""
+                name>=1.1,!=1.2;python_version=='2.7'
+                name>=2.0;python_version=='3.5'
+                name>=2.0;python_version=='3.6'
+                """),
+            },
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_constraints_with_markers_missing_one_req(self):
+        constraints_content = textwrap.dedent("""
+        name==1.1;python_version=='2.7'
+        name==2.0;python_version=='3.5'
+        name==2.0;python_version=='3.6'
+        """)
+        project_data = {
+            'requirements': {
+                'requirements.txt': textwrap.dedent("""
+                name>=1.1,!=1.2;python_version=='2.7'
+                name>=2.0;python_version=='3.5'
+                """),
+            },
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_constraints_with_markers_missing_one_marker(self):
+        constraints_content = textwrap.dedent("""
+        name==1.1;python_version=='2.7'
+        name==2.0;python_version=='3.5'
+        """)
+        project_data = {
+            'requirements': {
+                'requirements.txt': textwrap.dedent("""
+                name>=1.1,!=1.2;python_version=='2.7'
+                name>=2.0;python_version=='3.5'
+                name>=2.0;python_version=='3.6'
+                """),
+            },
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertTrue(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )
+
+    def test_complex_marker_evaluation(self):
+        constraints_content = textwrap.dedent("""
+        name===0.8.0;python_version=='2.7'
+        name===1.0.0;python_version>='3.0'
+        """)
+        project_data = {
+            'requirements': {
+                'requirements.txt': textwrap.dedent("""
+                name>=0.8.0;python_version<'3.0'  # BSD
+                name>=1.0.0;python_version>='3.0'  # BSD
+                """),
+            },
+            'lower-constraints.txt': constraints_content,
+        }
+        head_reqs = check.RequirementsList('testproj', project_data)
+        head_reqs.process(False)
+        self.assertFalse(
+            check.validate_lower_constraints(
+                req_list=head_reqs,
+                constraints=project_data['lower-constraints.txt'],
+                blacklist=requirement.parse(''),
+            )
+        )

openstack_requirements/tests/test_project.py

@@ -45,7 +45,8 @@ class TestReadProject(testtools.TestCase):
         root = self.useFixture(fixtures.TempDir()).path
         proj = project.read(root)
         self.expectThat(
-            proj, matchers.Equals({'root': root, 'requirements': {}}))
+            proj, matchers.Equals({'root': root, 'requirements': {},
+                                   'lower-constraints.txt': None}))
 
 
 class TestProjectExtras(testtools.TestCase):

playbooks/files/project-requirements-change.py

@@ -146,6 +146,15 @@ def main():
 
         failed = check.validate(head_reqs, branch_reqs, blacklist, global_reqs)
 
+        failed = (
+            check.validate_lower_constraints(
+                head_reqs,
+                head_proj['lower_constraints.txt'],
+                blacklist,
+            )
+            or failed
+        )
+
     # report the results
     if failed or head_reqs.failed or branch_reqs.failed:
         print("*** Incompatible requirement found!")