feat: Improve Gitea-compatible forge migrations, fix many migration bugs (#39424)

Supports migrating from Gitea-compatible forges like Forgejo and fixes
many migration bugs.

1. Pre-release and `+gitea-` suffixed server versions no longer drop
reviews, reactions and pagination.
2. Review states, dismissals, scoped and archived labels and merge bases
are migrated.
3. Disabled units, external trackers, unavailable release assets, and
GitLab confidential issues and internal notes are skipped.
4. Credentials are only sent to the source host, and `Retry-After` rate
limits are waited out.
5. GitHub migrations of only issues or pull requests, basic auth clones
and dismissed reviews work again.
6. The API returns 404 for releases of a disabled unit and shows
migrated authors as mannequins, replacing the never populated
`original_author` and `original_author_id` fields.

Fixes: https://github.com/go-gitea/gitea/issues/19533
Fixes: https://github.com/go-gitea/gitea/issues/35885
Fixes: https://github.com/go-gitea/gitea/issues/18275
Fixes: https://github.com/go-gitea/gitea/issues/35069
Fixes: https://github.com/go-gitea/gitea/issues/17763
Fixes: https://github.com/go-gitea/gitea/issues/39548
Co-authored-by: bircni <bircni@icloud.com>

models/issues/review_list.go

@@ -170,14 +170,22 @@ func GetReviewsByIssueID(ctx context.Context, issueID int64) (latestReviews, mig
 	// filter them in memory to get the latest review of each reviewer
 	// Since the reviews should not be too many for one issue, less than 100 commonly, it's acceptable to do this in memory
 	// And since there are too less indexes in review table, it will be very slow to filter in the database
-	reviewersMap := make(map[int64][]*Review)         // key is reviewer id
-	originalReviewersMap := make(map[int64][]*Review) // key is original author id
-	reviewTeamsMap := make(map[int64][]*Review)       // key is reviewer team id
+	type originalReviewer struct {
+		id   int64
+		name string
+	}
+	reviewersMap := make(map[int64][]*Review)                    // key is reviewer id
+	originalReviewersMap := make(map[originalReviewer][]*Review) // key is original author
+	reviewTeamsMap := make(map[int64][]*Review)                  // key is reviewer team id
 	countedReviewTypes := []ReviewType{ReviewTypeApprove, ReviewTypeReject, ReviewTypeRequest, ReviewTypeComment}
 	for _, review := range reviews {
 		if review.ReviewerTeamID == 0 && slices.Contains(countedReviewTypes, review.Type) && !review.Dismissed {
 			if review.OriginalAuthorID != 0 {
-				originalReviewersMap[review.OriginalAuthorID] = append(originalReviewersMap[review.OriginalAuthorID], review)
+				key := originalReviewer{id: review.OriginalAuthorID}
+				if review.OriginalAuthorID == user_model.GhostUserID {
+					key.name = review.OriginalAuthor
+				}
+				originalReviewersMap[key] = append(originalReviewersMap[key], review)
 			} else {
 				reviewersMap[review.ReviewerID] = append(reviewersMap[review.ReviewerID], review)
 			}

models/issues/review_test.go

@@ -194,6 +194,19 @@ func TestGetReviewersByIssueID(t *testing.T) {
 			assert.Equal(t, expectedReviews[i].UpdatedUnix, review.UpdatedUnix)
 		}
 	}
+
+	for _, review := range []*issues_model.Review{
+		{OriginalAuthor: "octocat", OriginalAuthorID: user_model.GhostUserID},
+		{OriginalAuthor: "hubot", OriginalAuthorID: user_model.GhostUserID},
+		{OriginalAuthor: "octocat", OriginalAuthorID: 583231},
+		{OriginalAuthor: "renamed-octocat", OriginalAuthorID: 583231},
+	} {
+		review.IssueID, review.Type = issue.ID, issues_model.ReviewTypeApprove
+		assert.NoError(t, db.Insert(t.Context(), review))
+	}
+	_, migratedReviews, err = issues_model.GetReviewsByIssueID(t.Context(), issue.ID)
+	assert.NoError(t, err)
+	assert.Len(t, migratedReviews, 3)
 }
 
 func TestDismissReview(t *testing.T) {