class-based DistroVersion

Author: vivus-ignis

src/gardenlinux/distro_version/__init__.py

@@ -9,43 +9,55 @@ class NotAPatchRelease(Exception):
     pass
 
 
-class DistroVersion:
-    major: Optional[int] = None
-    minor: Optional[int] = None
-    patch: Optional[int] = None
+def DistroVersion(maybe_distro_version):
+    version_components = maybe_distro_version.split(".")
+    if len(version_components) > 3 or len(version_components) < 2:
+        raise UnsupportedDistroVersion(
+            f"Unexpected version number format {maybe_distro_version}"
+        )
+
+    if not all(map(lambda x: x.isdigit(), version_components)):
+        raise UnsupportedDistroVersion(
+            f"Unexpected version number format {maybe_distro_version}"
+        )
 
-    def __init__(self, maybe_version_str):
-        version_components = maybe_version_str.split(".")
-        if len(version_components) > 3 or len(version_components) < 2:
-            raise UnsupportedDistroVersion(
-                f"Unexpected version number format {maybe_version_str}"
-            )
+    if len(version_components) == 2:
+        return LegacyDistroVersion(*(int(c) for c in version_components))
+    if len(version_components) == 3:
+        return SemverDistroVersion(*(int(c) for c in version_components))
 
-        if not all(map(lambda x: x.isdigit(), version_components)):
-            raise UnsupportedDistroVersion(
-                f"Unexpected version number format {maybe_version_str}"
-            )
 
-        self.major = int(version_components[0])
+class BaseDistroVersion:
+    def is_patch_release(self):
+        return self.patch and self.patch > 0
 
-        if len(version_components) == 2:
-            self.patch = int(version_components[1])
 
-        if len(version_components) == 3:
-            self.minor = int(version_components[1])
-            self.patch = int(version_components[2])
+class LegacyDistroVersion(BaseDistroVersion):
+    def __init__(self, major, patch):
+        self.major = major
+        self.patch = patch
 
     def __str__(self):
-        return (
-            f"{self.major}.{self.minor}.{self.patch - 1}"
-            if self.minor
-            else f"{self.major}.{self.patch - 1}"
-        )
+        return f"{self.major}.{self.patch}"
 
-    def is_patch_release(self):
-        return self.patch > 0
+    def previous_patch_release(self):
+        if not self.is_patch_release():
+            raise NotAPatchRelease(f"{self} is not a patch release")
+
+        return LegacyDistroVersion(self.major, self.patch - 1)
+
+
+class SemverDistroVersion(BaseDistroVersion):
+    def __init__(self, major, minor, patch):
+        self.major = major
+        self.minor = minor
+        self.patch = patch
+
+    def __str__(self):
+        return f"{self.major}.{self.minor}.{self.patch}"
 
     def previous_patch_release(self):
         if not self.is_patch_release():
             raise NotAPatchRelease(f"{self} is not a patch release")
-        return self.__str__()
+
+        return SemverDistroVersion(self.major, self.minor, self.patch - 1)

src/gardenlinux/github/release_notes/sections.py

@@ -107,7 +107,7 @@ def release_notes_compare_package_versions_section(gardenlinux_version, package_
     output = ""
 
     if version.is_patch_release():
-        previous_version = version.previous_patch_release()
+        previous_version = f"{version.previous_patch_release()}"
 
         output += f"## Changes in Package Versions Compared to {previous_version}\n"
         output += compare_apt_repo_versions(previous_version, gardenlinux_version)

tests/distro_version/test_distro_version.py

@@ -2,7 +2,9 @@
 
 from gardenlinux.distro_version import (
     DistroVersion,
+    LegacyDistroVersion,
     NotAPatchRelease,
+    SemverDistroVersion,
     UnsupportedDistroVersion,
 )
 
@@ -25,11 +27,11 @@ def test_distro_version_unrecognizable_too_short_version():
 
 
 def test_distro_version_legacy_version_is_parsable():
-    assert isinstance(DistroVersion("1.2"), DistroVersion)
+    assert isinstance(DistroVersion("1.2"), LegacyDistroVersion)
 
 
 def test_distro_version_semver_version_is_parsable():
-    assert isinstance(DistroVersion("1.2.3"), DistroVersion)
+    assert isinstance(DistroVersion("1.2.3"), SemverDistroVersion)
 
 
 def test_distro_version_patch_release_is_recognized():
@@ -40,8 +42,8 @@ def test_distro_version_patch_release_is_recognized():
 
 
 def test_distro_version_previous_patch_release_is_recognized():
-    assert DistroVersion("1.1").previous_patch_release() == "1.0"
-    assert DistroVersion("1.1.100").previous_patch_release() == "1.1.99"
+    assert DistroVersion("1.1").previous_patch_release().__str__() == "1.0"
+    assert DistroVersion("1.1.100").previous_patch_release().__str__() == "1.1.99"
     with pytest.raises(NotAPatchRelease):
         DistroVersion("1.0").previous_patch_release()
     with pytest.raises(NotAPatchRelease):