Merge "generate-constraints: Make use of ranges"

Author: Zuul

openstack_requirements/cmds/generate.py

@@ -127,6 +127,7 @@ def _combine_freezes(freezes, denylist=None):
     for py_version, freeze in freezes:
         if py_version in reference_versions:
             raise Exception("Duplicate python %s" % py_version)
+
         reference_versions.append(py_version)
         for package, version in freeze:
             packages.setdefault(
@@ -135,18 +136,29 @@ def _combine_freezes(freezes, denylist=None):
     for package, versions in sorted(packages.items()):
         if package.lower() in excludes:
             continue
-        if (len(versions) != 1 or
-                list(versions.values())[0] != reference_versions):
-            # markers
-            for version, py_versions in sorted(versions.items()):
-                # Once the ecosystem matures, we can consider using OR.
+
+        if len(versions) > 1:
+            # markers for packages with multiple versions - we use python
+            # version ranges for these
+            for idx, (version, py_versions) in enumerate(sorted(versions.items())):  # noqa: E501
+                if idx == 0:  # lower-bound
+                    marker = f"python_version<='{py_versions[-1]}'"
+                elif idx + 1 != len(versions):  # intermediate version(s)
+                    marker = f"python_version>='{py_versions[0]}',<={py_versions[-1]}"  # noqa: E501
+                else:  # upper-bound
+                    marker = f"python_version>='{py_versions[0]}'"
+
+                yield f'{package}==={version};{marker}\n'
+        elif list(versions.values())[0] != reference_versions:
+            # markers for packages with a single version - these are usually
+            # version specific so we use strict python versions for these
+            for idx, (version, py_versions) in enumerate(sorted(versions.items())):  # noqa: E501
                 for py_version in sorted(py_versions):
-                    yield (
-                        "%s===%s;python_version=='%s'\n" %
-                        (package, version, py_version))
+                    marker = f"python_version=='{py_version}'"
+                    yield f'{package}==={version};{marker}\n'
         else:
             # no markers
-            yield '%s===%s\n' % (package, list(versions.keys())[0])
+            yield f'{package}==={list(versions)[0]}\n'
 
 
 def _clone_versions(freezes, options):

openstack_requirements/tests/test_generate.py

@@ -89,8 +89,8 @@ def test_different_versions(self):
         freeze_27 = ('2.7', [('fixtures', '1.2.0')])
         freeze_34 = ('3.4', [('fixtures', '1.5.0')])
         self.assertEqual(
-            ["fixtures===1.2.0;python_version=='2.7'\n",
-             "fixtures===1.5.0;python_version=='3.4'\n"],
+            ["fixtures===1.2.0;python_version<='2.7'\n",
+             "fixtures===1.5.0;python_version>='3.4'\n"],
             list(generate._combine_freezes([freeze_27, freeze_34])))
 
     def test_duplicate_pythons(self):