plugins: only flag updates when remote head is not contained in local history (#3778)

* plugins: only flag updates when remote head is not contained in local history

* meta: remove inline comments

core/internal/plugins/registry.go

@@ -62,7 +62,7 @@ func (g *realGitClient) Pull(path string) error {
 	}
 
 	err = worktree.Pull(&git.PullOptions{})
-	if err != nil && err.Error() != "already up-to-date" {
+	if err != nil && !errors.Is(err, git.NoErrAlreadyUpToDate) {
 		return err
 	}
 
@@ -116,12 +116,30 @@ func (g *realGitClient) HasUpdates(path string) (bool, string, string, error) {
 		}
 	}
 
-	localHash := head.Hash().String()
+	localHash := head.Hash()
 	if remoteHead == "" {
-		return false, localHash, "", nil
+		return false, localHash.String(), "", nil
+	}
+	if localHash.String() == remoteHead {
+		return false, localHash.String(), remoteHead, nil
 	}
 
-	return localHash != remoteHead, localHash, remoteHead, nil
+	remoteCommit, err := repo.CommitObject(plumbing.NewHash(remoteHead))
+	if errors.Is(err, plumbing.ErrObjectNotFound) {
+		return true, localHash.String(), remoteHead, nil
+	}
+	if err != nil {
+		return false, "", "", err
+	}
+	headCommit, err := repo.CommitObject(localHash)
+	if err != nil {
+		return false, "", "", err
+	}
+	contained, err := remoteCommit.IsAncestor(headCommit)
+	if err != nil {
+		return false, "", "", err
+	}
+	return !contained, localHash.String(), remoteHead, nil
 }
 
 func (g *realGitClient) CurrentRevision(path string) (string, error) {

core/internal/plugins/registry_test.go

@@ -652,3 +652,37 @@ func TestRealGitClientChecksUpdatesWithoutFetching(t *testing.T) {
 	_, _, _, err = client.HasUpdates(localPath)
 	assert.Error(t, err)
 }
+
+func TestRealGitClientHasUpdatesIgnoresLocalAheadAfterRemoteRewind(t *testing.T) {
+	t.Setenv("GIT_CONFIG_GLOBAL", "")
+	t.Setenv("GIT_CONFIG_SYSTEM", "")
+	remotePath := t.TempDir()
+	remote, err := git.PlainInit(remotePath, false)
+	require.NoError(t, err)
+	worktree, err := remote.Worktree()
+	require.NoError(t, err)
+	signature := &object.Signature{Name: "DMS Test", Email: "[email protected]", When: time.Unix(1, 0)}
+	commit := func(content string) plumbing.Hash {
+		t.Helper()
+		require.NoError(t, os.WriteFile(filepath.Join(remotePath, "value.txt"), []byte(content), 0o644))
+		_, err := worktree.Add("value.txt")
+		require.NoError(t, err)
+		hash, err := worktree.Commit(content, &git.CommitOptions{Author: signature})
+		require.NoError(t, err)
+		return hash
+	}
+	first := commit("one")
+	second := commit("two")
+	localPath := t.TempDir()
+	_, err = git.PlainClone(localPath, &git.CloneOptions{URL: remotePath})
+	require.NoError(t, err)
+
+	require.NoError(t, remote.Storer.SetReference(plumbing.NewHashReference(plumbing.NewBranchReferenceName("master"), first)))
+
+	client := &realGitClient{}
+	updated, localHash, remoteHash, err := client.HasUpdates(localPath)
+	require.NoError(t, err)
+	assert.False(t, updated)
+	assert.Equal(t, second.String(), localHash)
+	assert.Equal(t, first.String(), remoteHash)
+}