fix: prevent panic when GitLab release has more links than sources (#36295)

The code incorrectly assumed rel.Assets.Links and rel.Assets.Sources
arrays have equal length. This causes index out of bounds panic when
migrating GitLab releases with more links than sources, which is common
with GoReleaser-generated releases.

Fixes #36292

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

services/migrations/github.go

@@ -329,7 +329,6 @@ func (g *GithubDownloaderV3) convertGithubRelease(ctx context.Context, rel *gith
 		r.Assets = append(r.Assets, &base.ReleaseAsset{
 			ID:            asset.GetID(),
 			Name:          asset.GetName(),
-			ContentType:   asset.ContentType,
 			Size:          asset.Size,
 			DownloadCount: asset.DownloadCount,
 			Created:       asset.CreatedAt.Time,

services/migrations/gitlab.go

@@ -316,12 +316,11 @@ func (g *GitlabDownloader) convertGitlabRelease(ctx context.Context, rel *gitlab
 
 	httpClient := NewMigrationHTTPClient()
 
-	for k, asset := range rel.Assets.Links {
+	for _, asset := range rel.Assets.Links {
 		assetID := asset.ID // Don't optimize this, for closure we need a local variable
 		r.Assets = append(r.Assets, &base.ReleaseAsset{
 			ID:            int64(asset.ID),
 			Name:          asset.Name,
-			ContentType:   &rel.Assets.Sources[k].Format,
 			Size:          &zero,
 			DownloadCount: &zero,
 			DownloadFunc: func() (io.ReadCloser, error) {

services/migrations/main_test.go

@@ -171,7 +171,6 @@ func assertReactionsEqual(t *testing.T, expected, actual []*base.Reaction) {
 func assertReleaseAssetEqual(t *testing.T, expected, actual *base.ReleaseAsset) {
 	assert.Equal(t, expected.ID, actual.ID)
 	assert.Equal(t, expected.Name, actual.Name)
-	assert.Equal(t, expected.ContentType, actual.ContentType)
 	assert.Equal(t, expected.Size, actual.Size)
 	assert.Equal(t, expected.DownloadCount, actual.DownloadCount)
 	assertTimeEqual(t, expected.Created, actual.Created)