refactor(changelog): add get_next_tag_name_after_version and test, mark unused for get_smart_tag_range

Author: bearomorphism

commitizen/changelog.py

@@ -281,6 +281,18 @@ def incremental_build(
     return output_lines
 
 
+def get_next_tag_name_after_version(tags: Sequence[GitTag], version: str) -> str | None:
+    idx = len(tags) - 1
+    while idx >= 0:
+        if tags[idx].name == version:
+            if idx == len(tags) - 1:
+                return None
+            return tags[idx + 1].name
+        idx -= 1
+    raise NoCommitsFoundError(f"Could not find a valid revision range. {version=}")
+
+
+# TODO: unused, deprecate this?
 def get_smart_tag_range(
     tags: Sequence[GitTag], newest: str, oldest: str | None = None
 ) -> list[GitTag]:
@@ -331,15 +343,13 @@ def get_tag_name(v: str) -> str:
     newest_tag_name = get_tag_name(newest_version)
     oldest_tag_name = get_tag_name(oldest_version) if oldest_version else None
 
-    tags_range = get_smart_tag_range(tags, newest_tag_name, oldest_tag_name)
-    if not tags_range:
-        raise NoCommitsFoundError("Could not find a valid revision range.")
-
-    oldest_rev: str | None = tags_range[-1].name
+    oldest_rev = get_next_tag_name_after_version(
+        tags, oldest_tag_name or newest_tag_name
+    )
 
     # Return None for oldest_rev if:
     # 1. The oldest tag is the last tag in the list and matches the requested oldest tag
     # 2. The oldest and the newest tag are the same
-    if oldest_rev == oldest_tag_name == tags[-1].name or oldest_rev == newest_tag_name:
-        oldest_rev = None
+    if oldest_rev == newest_tag_name:
+        return None, newest_tag_name
     return oldest_rev, newest_tag_name

tests/test_changelog.py

@@ -1535,6 +1535,24 @@ def test_get_smart_tag_range_returns_an_extra_for_a_single_tag(tags):
     assert 2 == len(res)
 
 
+def test_get_next_tag_name_after_version(tags):
+    # Test finding next tag after a version
+    next_tag_name = changelog.get_next_tag_name_after_version(tags, "v1.2.0")
+    assert next_tag_name == "v1.1.1"
+
+    next_tag_name = changelog.get_next_tag_name_after_version(tags, "v1.1.0")
+    assert next_tag_name == "v1.0.0"
+
+    # Test finding last tag when given version is last
+    last_tag_name = changelog.get_next_tag_name_after_version(tags, "v0.9.1")
+    assert last_tag_name is None
+
+    # Test error when version not found
+    with pytest.raises(changelog.NoCommitsFoundError) as exc_info:
+        changelog.get_next_tag_name_after_version(tags, "nonexistent")
+    assert "Could not find a valid revision range" in str(exc_info.value)
+
+
 @dataclass
 class TagDef:
     name: str