refactor: extract tag object creation and improve annotation handling

Co-authored-by: jimeh <39563+jimeh@users.noreply.github.com>

__tests__/main.test.ts

@@ -721,6 +721,33 @@ describe('run', () => {
       expect(core.setOutput).toHaveBeenCalledWith('created', ['v1.0.0'])
     })
 
+    it('creates lightweight tags when annotation is only whitespace', async () => {
+      setupInputs({
+        tags: 'v1.0.0',
+        ref: 'abc123',
+        github_token: 'test-token',
+        when_exists: 'update',
+        annotation: '   '
+      })
+      setupCommitResolver('sha-abc123')
+      setupTagDoesNotExist()
+
+      await run()
+
+      // Should NOT create tag object for whitespace-only annotation
+      expect(github.mockOctokit.rest.git.createTag).not.toHaveBeenCalled()
+
+      // Should create reference pointing directly to commit
+      expect(github.mockOctokit.rest.git.createRef).toHaveBeenCalledWith({
+        owner: 'test-owner',
+        repo: 'test-repo',
+        ref: 'refs/tags/v1.0.0',
+        sha: 'sha-abc123'
+      })
+
+      expect(core.setOutput).toHaveBeenCalledWith('created', ['v1.0.0'])
+    })
+
     it('updates tags with annotation', async () => {
       setupInputs({
         tags: 'v1',

src/tags.ts

@@ -170,6 +170,36 @@ export async function processTag(
   }
 }
 
+/**
+ * Create a tag object for an annotated tag.
+ *
+ * @param tagName - Name of the tag
+ * @param sha - Commit SHA to tag
+ * @param annotation - Annotation message
+ * @param owner - Repository owner
+ * @param repo - Repository name
+ * @param octokit - GitHub API client
+ * @returns SHA of the created tag object
+ */
+async function createTagObject(
+  tagName: string,
+  sha: string,
+  annotation: string,
+  owner: string,
+  repo: string,
+  octokit: ReturnType<typeof github.getOctokit>
+): Promise<string> {
+  const tagObject = await octokit.rest.git.createTag({
+    owner,
+    repo,
+    tag: tagName,
+    message: annotation,
+    object: sha,
+    type: 'commit'
+  })
+  return tagObject.data.sha
+}
+
 /**
  * Create a tag (annotated or lightweight based on annotation parameter).
  *
@@ -190,17 +220,16 @@ async function createTag(
 ): Promise<void> {
   let refSha = sha
 
-  // If annotation is provided, create an annotated tag object first
-  if (annotation) {
-    const tagObject = await octokit.rest.git.createTag({
+  // If annotation is provided and non-empty, create an annotated tag object first
+  if (annotation && annotation.trim()) {
+    refSha = await createTagObject(
+      tagName,
+      sha,
+      annotation,
       owner,
       repo,
-      tag: tagName,
-      message: annotation,
-      object: sha,
-      type: 'commit'
-    })
-    refSha = tagObject.data.sha
+      octokit
+    )
   }
 
   // Create the reference pointing to the tag object (or commit for lightweight)
@@ -232,17 +261,16 @@ async function updateTag(
 ): Promise<void> {
   let refSha = sha
 
-  // If annotation is provided, create an annotated tag object first
-  if (annotation) {
-    const tagObject = await octokit.rest.git.createTag({
+  // If annotation is provided and non-empty, create an annotated tag object first
+  if (annotation && annotation.trim()) {
+    refSha = await createTagObject(
+      tagName,
+      sha,
+      annotation,
       owner,
       repo,
-      tag: tagName,
-      message: annotation,
-      object: sha,
-      type: 'commit'
-    })
-    refSha = tagObject.data.sha
+      octokit
+    )
   }
 
   // Update the reference