RepoVersionInfo: Add a method to find the last tag

This method gets the last tag if we are at a tag or the last tag
matching the current branch major and minor (if any) if we are at a
branch.

Useful for calculating minimal dependencies.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/repo/config/version.py

@@ -326,6 +326,27 @@ def branches(self) -> dict[str, BranchVersion]:
         """
         return self._branches
 
+    def find_last_tag(self) -> semver.Version | None:
+        """Find the last tag.
+
+        Returns:
+            If we are at a tag, return the [current
+                tag][frequenz.repo.config.version.RepoVersionInfo.current_tag]. If we
+                are at a branch, return the last tag matching the branch major and minor
+                (if any). If there are no matching tags, return `None`.
+        """
+        if self._current_tag:
+            return self._current_tag
+        branch = self.current_branch
+        if branch is None:
+            return None
+        tags = [t for t in self._tags.values() if t.major == branch.major]
+        if branch.minor is not None:
+            tags = [t for t in tags if t.minor == branch.minor]
+        if not tags:
+            return None
+        return max(tags)
+
     def find_next_minor_for_major_branch(self) -> int | None:
         """Find the next minor version for the current major branch.
 

tests/test_version.py

@@ -176,6 +176,7 @@ class _Expected:  # pylint: disable=too-many-instance-attributes
     is_tag: bool = False
     is_tag_last_minor_for_major: bool = False
     is_tag_latest: bool = False
+    last_tag: semver.Version | None = None
     # Branch
     current_branch: BranchVersion | None = None
     is_branch: bool = False
@@ -212,6 +213,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(1, 0, 1),
             is_tag=True,
             is_tag_last_minor_for_major=True,
+            last_tag=semver.Version(1, 0, 1),
         ),
     ),
     _TestCase(
@@ -223,6 +225,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(1, 1, 0),
             is_tag=True,
             is_tag_last_minor_for_major=True,
+            last_tag=semver.Version(1, 1, 0),
         ),
     ),
     _TestCase(
@@ -234,6 +237,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(2, 0, 1),
             is_tag=True,
             is_tag_last_minor_for_major=False,
+            last_tag=semver.Version(2, 0, 1),
         ),
     ),
     _TestCase(
@@ -247,6 +251,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             is_tag=True,
             is_tag_last_minor_for_major=True,
             is_tag_latest=True,
+            last_tag=semver.Version(3, 0, 0),
         ),
     ),
     _TestCase(
@@ -259,6 +264,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             is_tag=True,
             is_tag_last_minor_for_major=True,
             is_tag_latest=True,
+            last_tag=semver.Version(2, 1, 0),
         ),
     ),
     _TestCase(
@@ -272,6 +278,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             is_tag=True,
             is_tag_last_minor_for_major=True,
             is_tag_latest=True,
+            last_tag=semver.Version(2, 1, 1),
         ),
     ),
     _TestCase(
@@ -283,6 +290,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             ref_name="v1.0.2-alpha.1",
             current_tag=semver.Version(1, 0, 2, "alpha.1"),
             is_tag=True,
+            last_tag=semver.Version(1, 0, 2, "alpha.1"),
         ),
     ),
     _TestCase(
@@ -295,6 +303,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(1, 1, 0, "beta"),
             is_tag=True,
             is_tag_last_minor_for_major=True,
+            last_tag=semver.Version(1, 1, 0, "beta"),
         ),
     ),
     _TestCase(
@@ -308,6 +317,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             is_tag=True,
             is_tag_last_minor_for_major=True,
             is_tag_latest=True,
+            last_tag=semver.Version(3, 0, 0, "rc1"),
         ),
     ),
     _TestCase(
@@ -321,6 +331,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             is_tag=True,
             is_tag_last_minor_for_major=True,
             is_tag_latest=True,
+            last_tag=semver.Version(2, 1, 0, "alpha.1"),
         ),
     ),
     _TestCase(
@@ -334,6 +345,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             is_tag=True,
             is_tag_last_minor_for_major=True,
             is_tag_latest=True,
+            last_tag=semver.Version(2, 0, 1, "rc1"),
         ),
     ),
     _TestCase(
@@ -355,6 +367,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_branch=BranchVersion(major=1, minor=None, name="v1.x.x"),
             is_branch=True,
             next_minor_for_major_branch=1,
+            last_tag=semver.Version(1, 1, 0, "rc"),
         ),
     ),
     _TestCase(
@@ -365,6 +378,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             ref_name="v1.0.x",
             current_branch=BranchVersion(major=1, minor=0, name="v1.0.x"),
             is_branch=True,
+            last_tag=semver.Version(1, 0, 2, "alpha.1"),
         ),
     ),
     _TestCase(
@@ -377,6 +391,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(1, 0, 0),
             is_tag=True,
             is_tag_last_minor_for_major=True,
+            last_tag=semver.Version(1, 0, 0),
         ),
     ),
     _TestCase(
@@ -389,6 +404,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(1, 0, 2),
             is_tag=True,
             is_tag_last_minor_for_major=True,
+            last_tag=semver.Version(1, 0, 2),
         ),
     ),
     _TestCase(
@@ -400,6 +416,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             ref_name="v2.0.1",
             current_tag=semver.Version(2, 0, 1),
             is_tag=True,
+            last_tag=semver.Version(2, 0, 1),
         ),
     ),
     _TestCase(
@@ -413,6 +430,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_tag=semver.Version(1, 0, 0),
             is_tag=True,
             is_tag_last_minor_for_major=True,
+            last_tag=semver.Version(1, 0, 0),
         ),
     ),
     _TestCase(
@@ -437,6 +455,7 @@ class _TestCase:  # pylint: disable=too-many-instance-attributes
             current_branch=BranchVersion(major=1, minor=None, name="v1.x.x"),
             is_branch=True,
             next_minor_for_major_branch=1,
+            last_tag=semver.Version(1, 1, 0, "rc"),
         ),
     ),
     _TestCase(
@@ -488,3 +507,9 @@ def test_repo_version(
     )
     assert repo_version_info.is_tag_latest() == case.expected.is_tag_latest
     assert repo_version_info.is_branch_latest() == case.expected.is_branch_latest
+    if case.expected.last_tag is None:
+        assert repo_version_info.find_last_tag() is None
+    else:
+        last_tag = repo_version_info.find_last_tag()
+        assert last_tag is not None
+        assert last_tag == case.expected.last_tag