fix(migrations): wait out GitHub rate limits and tolerate failed patch downloads (#40012)

Large GitHub migrations failed once the API budget ran out. A rejected
request never updated the downloader's rate state, so go-github refused
every retry locally.

- Record the rate limit from error responses too, so the next request
waits for the reset
- Retry repository-wide comment pages like the other downloader calls
- Stop `waitAndPickClient` spinning when the rate refresh fails
- Skip reaction requests when the reaction rollup reports none
- Log a failed patch download instead of failing the migration

---------

Co-authored-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Giteabot <teabot@gitea.io>

modules/migration/retry_downloader.go

@@ -154,6 +154,21 @@ func (d *RetryDownloader) GetComments(ctx context.Context, commentable Commentab
 	return comments, isEnd, err
 }
 
+func (d *RetryDownloader) GetAllComments(ctx context.Context, page, perPage int) ([]*Comment, bool, error) {
+	var (
+		comments []*Comment
+		isEnd    bool
+		err      error
+	)
+
+	err = d.retry(ctx, func(ctx context.Context) error {
+		comments, isEnd, err = d.Downloader.GetAllComments(ctx, page, perPage)
+		return err
+	})
+
+	return comments, isEnd, err
+}
+
 // GetPullRequests returns a repository's pull requests with retry
 func (d *RetryDownloader) GetPullRequests(ctx context.Context, page, perPage int) ([]*PullRequest, bool, error) {
 	var (

modules/migration/retry_downloader_test.go

@@ -11,12 +11,19 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestRetryDownloaderExhaustsAttempts(t *testing.T) {
-	failure := errors.New("permission denied")
-	attempts := 0
-	assert.ErrorIs(t, NewRetryDownloader(nil, 3, 0).retry(t.Context(), func(_ctx context.Context) error {
-		attempts++
-		return failure
-	}), failure)
-	assert.Equal(t, 3, attempts)
+type failingCommentsDownloader struct {
+	NullDownloader
+	attempts int
+}
+
+func (d *failingCommentsDownloader) GetAllComments(_ctx context.Context, _page, _perPage int) ([]*Comment, bool, error) {
+	d.attempts++
+	return nil, false, errors.New("permission denied")
+}
+
+func TestRetryDownloaderExhaustsAttempts(t *testing.T) {
+	source := &failingCommentsDownloader{}
+	_, _, err := NewRetryDownloader(source, 3, 0).GetAllComments(t.Context(), 1, 50)
+	assert.EqualError(t, err, "permission denied")
+	assert.Equal(t, 3, source.attempts)
 }

services/migrations/gitea_uploader.go

@@ -508,15 +508,15 @@ func (g *GiteaLocalUploader) CreateComments(ctx context.Context, comments ...*ba
 			}
 		case issues_model.CommentTypeChangeTitle:
 			if comment.Meta["OldTitle"] != nil {
-				cm.OldTitle = fmt.Sprint(comment.Meta["OldTitle"])
+				cm.OldTitle = util.TruncateRunes(fmt.Sprint(comment.Meta["OldTitle"]), 255)
 			}
 			if comment.Meta["NewTitle"] != nil {
-				cm.NewTitle = fmt.Sprint(comment.Meta["NewTitle"])
+				cm.NewTitle = util.TruncateRunes(fmt.Sprint(comment.Meta["NewTitle"]), 255)
 			}
 		case issues_model.CommentTypeChangeTargetBranch:
 			if comment.Meta["OldRef"] != nil && comment.Meta["NewRef"] != nil {
-				cm.OldRef = fmt.Sprint(comment.Meta["OldRef"])
-				cm.NewRef = fmt.Sprint(comment.Meta["NewRef"])
+				cm.OldRef = util.TruncateRunes(fmt.Sprint(comment.Meta["OldRef"]), 255)
+				cm.NewRef = util.TruncateRunes(fmt.Sprint(comment.Meta["NewRef"]), 255)
 				cm.Content = ""
 			}
 		case issues_model.CommentTypeLabel:
@@ -540,7 +540,7 @@ func (g *GiteaLocalUploader) CreateComments(ctx context.Context, comments ...*ba
 				continue
 			}
 		case issues_model.CommentTypeDeleteBranch:
-			cm.OldRef = comment.Content
+			cm.OldRef = util.TruncateRunes(comment.Content, 255)
 			cm.Content = ""
 		case issues_model.CommentTypeMergePull:
 			cm.Content = ""
@@ -630,7 +630,7 @@ func (g *GiteaLocalUploader) updateGitForPullRequest(ctx context.Context, pr *ba
 	}
 
 	// Anonymous function to download the patch file (allows us to use defer)
-	err = func() error {
+	if err := func() error {
 		// if the patchURL is empty there is nothing to download
 		if pr.PatchURL == "" {
 			return nil
@@ -656,9 +656,8 @@ func (g *GiteaLocalUploader) updateGitForPullRequest(ctx context.Context, pr *ba
 		_, err = io.Copy(f, ret)
 
 		return err
-	}()
-	if err != nil {
-		return "", err
+	}(); err != nil { // the patch is only a fallback for a missing head ref
+		log.Warn("PR #%d in %s/%s: unable to download patch: %v", pr.Number, g.repoOwner, g.repoName, err)
 	}
 
 	head = "unknown repository"

services/migrations/gitea_uploader_test.go

@@ -203,6 +203,7 @@ func TestGiteaUploadRemapLocalUser(t *testing.T) {
 			&base.Comment{IssueIndex: issue.Index, CommentType: "milestone", Meta: map[string]any{"MilestoneTitle": milestone.Name}},
 			&base.Comment{IssueIndex: issue.Index, CommentType: "milestone", Meta: map[string]any{"MilestoneTitle": milestone.Name, "Removed": true}},
 			&base.Comment{IssueIndex: issue.Index, CommentType: "delete_branch", Content: "feature"},
+			&base.Comment{IssueIndex: issue.Index, CommentType: "delete_branch", Content: strings.Repeat("a", 256)},
 		))
 
 		unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{IssueID: issue.ID, Type: issues_model.CommentTypeLabel, LabelID: label.ID, Content: "1"})
@@ -214,6 +215,7 @@ func TestGiteaUploadRemapLocalUser(t *testing.T) {
 		unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{IssueID: issue.ID, Type: issues_model.CommentTypeMilestone, MilestoneID: milestone.ID})
 		unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{IssueID: issue.ID, Type: issues_model.CommentTypeMilestone, OldMilestoneID: milestone.ID})
 		assert.Empty(t, unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{IssueID: issue.ID, Type: issues_model.CommentTypeDeleteBranch, OldRef: "feature"}).Content)
+		assert.Empty(t, unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{IssueID: issue.ID, Type: issues_model.CommentTypeDeleteBranch, OldRef: strings.Repeat("a", 255)}).Content)
 	})
 }
 
@@ -332,6 +334,7 @@ func TestGiteaUploadForkPullRequestHeadInRepository(t *testing.T) {
 		Head:   base.PullRequestBranch{OwnerName: "fork-owner", RepoName: "repo", Ref: "feature", SHA: headCommitID, CloneURL: "https://fork.invalid/fork-owner/repo.git"},
 		Base:   base.PullRequestBranch{OwnerName: repo.OwnerName, RepoName: repo.Name, Ref: repo.DefaultBranch},
 	}
+	pr.PatchURL = "file:///nonexistent.patch"
 	pr.EnsuredSafe = true
 	require.True(t, pr.IsForkPullRequest())
 

services/migrations/github.go

@@ -167,6 +167,7 @@ func (g *GithubDownloaderV3) waitAndPickClient(ctx context.Context) {
 		err := g.RefreshRate(ctx)
 		if err != nil {
 			log.Error("g.getClient().RateLimit.Get: %s", err)
+			return // the stale reset time is in the past, so looping would spin
 		}
 	}
 }
@@ -195,14 +196,20 @@ func (g *GithubDownloaderV3) setRate(rate *github.Rate) {
 	g.rates[g.curClientIdx] = rate
 }
 
+func (g *GithubDownloaderV3) setRateFromResponse(resp *github.Response) {
+	if resp != nil && resp.Rate.Limit > 0 {
+		g.setRate(&resp.Rate)
+	}
+}
+
 // GetRepoInfo returns a repository information
 func (g *GithubDownloaderV3) GetRepoInfo(ctx context.Context) (*base.Repository, error) {
 	g.waitAndPickClient(ctx)
 	gr, resp, err := g.getClient().Repositories.Get(ctx, g.repoOwner, g.repoName)
+	g.setRateFromResponse(resp)
 	if err != nil {
 		return nil, err
 	}
-	g.setRate(&resp.Rate)
 
 	// convert github repo to stand Repo
 	return &base.Repository{
@@ -221,10 +228,10 @@ func (g *GithubDownloaderV3) GetRepoInfo(ctx context.Context) (*base.Repository,
 func (g *GithubDownloaderV3) GetTopics(ctx context.Context) ([]string, error) {
 	g.waitAndPickClient(ctx)
 	r, resp, err := g.getClient().Repositories.Get(ctx, g.repoOwner, g.repoName)
+	g.setRateFromResponse(resp)
 	if err != nil {
 		return nil, err
 	}
-	g.setRate(&resp.Rate)
 	return r.Topics, nil
 }
 
@@ -242,10 +249,10 @@ func (g *GithubDownloaderV3) GetMilestones(ctx context.Context) ([]*base.Milesto
 					PerPage: perPage,
 				},
 			})
+		g.setRateFromResponse(resp)
 		if err != nil {
 			return nil, err
 		}
-		g.setRate(&resp.Rate)
 
 		for _, m := range ms {
 			state := "open"
@@ -288,10 +295,10 @@ func (g *GithubDownloaderV3) GetLabels(ctx context.Context) ([]*base.Label, erro
 				Page:    i,
 				PerPage: perPage,
 			})
+		g.setRateFromResponse(resp)
 		if err != nil {
 			return nil, err
 		}
-		g.setRate(&resp.Rate)
 
 		for _, label := range ls {
 			labels = append(labels, convertGithubLabel(label))
@@ -387,10 +394,10 @@ func (g *GithubDownloaderV3) GetReleases(ctx context.Context) ([]*base.Release,
 				Page:    i,
 				PerPage: perPage,
 			})
+		g.setRateFromResponse(resp)
 		if err != nil {
 			return nil, err
 		}
-		g.setRate(&resp.Rate)
 
 		for _, release := range ls {
 			releases = append(releases, g.convertGithubRelease(ctx, release))
@@ -429,49 +436,20 @@ func (g *GithubDownloaderV3) GetIssues(ctx context.Context, page, perPage int) (
 	allIssues := make([]*base.Issue, 0, perPage)
 	g.waitAndPickClient(ctx)
 	issues, resp, err := g.getClient().Issues.ListByRepo(ctx, g.repoOwner, g.repoName, opt)
+	g.setRateFromResponse(resp)
 	if err != nil {
 		return nil, false, fmt.Errorf("GetIssues: %w", err)
 	}
 	log.Trace("Request get issues %d/%d, but in fact get %d", perPage, page, len(issues))
-	g.setRate(&resp.Rate)
 	for _, issue := range issues {
 		if issue.IsPullRequest() {
 			continue
 		}
-
-		labels := make([]*base.Label, 0, len(issue.Labels))
-		for _, l := range issue.Labels {
-			labels = append(labels, convertGithubLabel(l))
-		}
-
-		reactions, err := g.getIssueReactions(ctx, issue.GetNumber(), perPage)
+		converted, err := g.convertGithubIssue(ctx, issue, perPage)
 		if err != nil {
 			return nil, false, err
 		}
-
-		var assignees []string
-		for i := range issue.Assignees {
-			assignees = append(assignees, issue.Assignees[i].GetLogin())
-		}
-
-		allIssues = append(allIssues, &base.Issue{
-			Title:        *issue.Title,
-			Number:       int64(*issue.Number),
-			PosterID:     issue.GetUser().GetID(),
-			PosterName:   issue.GetUser().GetLogin(),
-			PosterEmail:  issue.GetUser().GetEmail(),
-			Content:      issue.GetBody(),
-			Milestone:    issue.GetMilestone().GetTitle(),
-			State:        issue.GetState(),
-			Created:      issue.GetCreatedAt().Time,
-			Updated:      issue.GetUpdatedAt().Time,
-			Labels:       labels,
-			Reactions:    reactions,
-			Closed:       issue.ClosedAt.GetTime(),
-			IsLocked:     issue.GetLocked(),
-			Assignees:    assignees,
-			ForeignIndex: int64(*issue.Number),
-		})
+		allIssues = append(allIssues, converted)
 	}
 
 	g.issuePage, g.issueCursor, g.nextIssueCursor = page, opt.After, resp.After
@@ -485,6 +463,82 @@ func (g *GithubDownloaderV3) isLastPage(resp *github.Response, n, perPage int) b
 	return resp.NextPage == 0 && resp.After == ""
 }
 
+func (g *GithubDownloaderV3) convertGithubIssue(ctx context.Context, issue *github.Issue, perPage int) (*base.Issue, error) {
+	labels := make([]*base.Label, 0, len(issue.Labels))
+	for _, l := range issue.Labels {
+		labels = append(labels, convertGithubLabel(l))
+	}
+
+	// get reactions
+	var reactions []*base.Reaction
+	if !g.SkipReactions && (issue.Reactions == nil || issue.Reactions.TotalCount == nil || issue.Reactions.GetTotalCount() > 0) {
+		for i := 1; ; i++ {
+			g.waitAndPickClient(ctx)
+			res, resp, err := g.getClient().Reactions.ListIssueReactions(ctx, g.repoOwner, g.repoName, issue.GetNumber(), &github.ListReactionOptions{
+				ListOptions: github.ListOptions{
+					Page:    i,
+					PerPage: perPage,
+				},
+			})
+			g.setRateFromResponse(resp)
+			if err != nil {
+				return nil, err
+			}
+			if len(res) == 0 {
+				break
+			}
+			for _, reaction := range res {
+				reactions = append(reactions, &base.Reaction{
+					UserID:   reaction.User.GetID(),
+					UserName: reaction.User.GetLogin(),
+					Content:  reaction.GetContent(),
+				})
+			}
+		}
+	}
+
+	var assignees []string
+	for i := range issue.Assignees {
+		assignees = append(assignees, issue.Assignees[i].GetLogin())
+	}
+
+	return &base.Issue{
+		Title:        issue.GetTitle(),
+		Number:       int64(issue.GetNumber()),
+		PosterID:     issue.GetUser().GetID(),
+		PosterName:   issue.GetUser().GetLogin(),
+		PosterEmail:  issue.GetUser().GetEmail(),
+		Content:      issue.GetBody(),
+		Milestone:    issue.GetMilestone().GetTitle(),
+		State:        issue.GetState(),
+		Created:      issue.GetCreatedAt().Time,
+		Updated:      issue.GetUpdatedAt().Time,
+		Labels:       labels,
+		Reactions:    reactions,
+		Closed:       issue.ClosedAt.GetTime(),
+		IsLocked:     issue.GetLocked(),
+		Assignees:    assignees,
+		ForeignIndex: int64(issue.GetNumber()),
+	}, nil
+}
+
+// GetIssue recovers an issue omitted from the repository listing.
+func (g *GithubDownloaderV3) GetIssue(ctx context.Context, number int64) (*base.Issue, error) {
+	g.waitAndPickClient(ctx)
+	issue, resp, err := g.getClient().Issues.Get(ctx, g.repoOwner, g.repoName, int(number))
+	g.setRateFromResponse(resp)
+	if err != nil {
+		return nil, err
+	}
+	if issue.IsPullRequest() {
+		return nil, fmt.Errorf("issue %d is a pull request", number)
+	}
+	if int64(issue.GetNumber()) != number {
+		return nil, fmt.Errorf("GitHub returned issue %d while recovering issue %d", issue.GetNumber(), number)
+	}
+	return g.convertGithubIssue(ctx, issue, g.maxPerPage)
+}
+
 // SupportGetRepoComments return true if it supports get repo comments
 func (g *GithubDownloaderV3) SupportGetRepoComments() bool {
 	return true
@@ -512,14 +566,14 @@ func (g *GithubDownloaderV3) getComments(ctx context.Context, commentable base.C
 	for {
 		g.waitAndPickClient(ctx)
 		comments, resp, err := g.getClient().Issues.ListComments(ctx, g.repoOwner, g.repoName, int(commentable.GetForeignIndex()), opt)
+		g.setRateFromResponse(resp)
 		if err != nil {
 			return nil, fmt.Errorf("error while listing repos: %w", err)
 		}
-		g.setRate(&resp.Rate)
 		for _, comment := range comments {
 			// get reactions
 			var reactions []*base.Reaction
-			if !g.SkipReactions {
+			if !g.SkipReactions && mayHaveReactions(comment.Reactions) {
 				for i := 1; ; i++ {
 					g.waitAndPickClient(ctx)
 					res, resp, err := g.getClient().Reactions.ListIssueCommentReactions(ctx, g.repoOwner, g.repoName, comment.GetID(), &github.ListReactionOptions{
@@ -528,10 +582,10 @@ func (g *GithubDownloaderV3) getComments(ctx context.Context, commentable base.C
 							PerPage: g.maxPerPage,
 						},
 					})
+					g.setRateFromResponse(resp)
 					if err != nil {
 						return nil, err
 					}
-					g.setRate(&resp.Rate)
 					if len(res) == 0 {
 						break
 					}
@@ -586,17 +640,17 @@ func (g *GithubDownloaderV3) GetAllComments(ctx context.Context, page, perPage i
 
 	g.waitAndPickClient(ctx)
 	comments, resp, err := g.getClient().Issues.ListComments(ctx, g.repoOwner, g.repoName, 0, opt)
+	g.setRateFromResponse(resp)
 	if err != nil {
 		return nil, false, fmt.Errorf("error while listing repos: %w", err)
 	}
 	isEnd := resp.NextPage == 0
 
 	log.Trace("Request get comments %d/%d, but in fact get %d, next page is %d", perPage, page, len(comments), resp.NextPage)
-	g.setRate(&resp.Rate)
 	for _, comment := range comments {
 		// get reactions
 		var reactions []*base.Reaction
-		if !g.SkipReactions {
+		if !g.SkipReactions && mayHaveReactions(comment.Reactions) {
 			for i := 1; ; i++ {
 				g.waitAndPickClient(ctx)
 				res, resp, err := g.getClient().Reactions.ListIssueCommentReactions(ctx, g.repoOwner, g.repoName, comment.GetID(), &github.ListReactionOptions{
@@ -605,10 +659,10 @@ func (g *GithubDownloaderV3) GetAllComments(ctx context.Context, page, perPage i
 						PerPage: g.maxPerPage,
 					},
 				})
+				g.setRateFromResponse(resp)
 				if err != nil {
 					return nil, false, err
 				}
-				g.setRate(&resp.Rate)
 				if len(res) == 0 {
 					break
 				}
@@ -656,11 +710,11 @@ func (g *GithubDownloaderV3) GetPullRequests(ctx context.Context, page, perPage
 	allPRs := make([]*base.PullRequest, 0, perPage)
 	g.waitAndPickClient(ctx)
 	prs, resp, err := g.getClient().PullRequests.List(ctx, g.repoOwner, g.repoName, opt)
+	g.setRateFromResponse(resp)
 	if err != nil {
 		return nil, false, fmt.Errorf("error while listing repos: %w", err)
 	}
 	log.Trace("Request get pull requests %d/%d, but in fact get %d", perPage, page, len(prs))
-	g.setRate(&resp.Rate)
 	for _, pr := range prs {
 		basePR, err := g.convertGithubPullRequest(ctx, pr, perPage)
 		if err != nil {
@@ -681,7 +735,7 @@ func (g *GithubDownloaderV3) convertGithubPullRequest(ctx context.Context, pr *g
 		labels = append(labels, convertGithubLabel(l))
 	}
 
-	reactions, err := g.getIssueReactions(ctx, pr.GetNumber(), perPage)
+	reactions, err := g.getIssueReactions(ctx, pr.GetNumber(), perPage, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -725,8 +779,12 @@ func (g *GithubDownloaderV3) convertGithubPullRequest(ctx context.Context, pr *g
 	}, nil
 }
 
-func (g *GithubDownloaderV3) getIssueReactions(ctx context.Context, number, perPage int) ([]*base.Reaction, error) {
-	if g.SkipReactions {
+func mayHaveReactions(reactions *github.Reactions) bool {
+	return reactions == nil || reactions.TotalCount == nil || *reactions.TotalCount > 0
+}
+
+func (g *GithubDownloaderV3) getIssueReactions(ctx context.Context, number, perPage int, rollup *github.Reactions) ([]*base.Reaction, error) {
+	if g.SkipReactions || !mayHaveReactions(rollup) {
 		return nil, nil
 	}
 	var reactions []*base.Reaction
@@ -738,10 +796,10 @@ func (g *GithubDownloaderV3) getIssueReactions(ctx context.Context, number, perP
 				PerPage: perPage,
 			},
 		})
+		g.setRateFromResponse(resp)
 		if err != nil {
 			return nil, err
 		}
-		g.setRate(&resp.Rate)
 		if len(res) == 0 {
 			return reactions, nil
 		}
@@ -774,7 +832,7 @@ func (g *GithubDownloaderV3) convertGithubReviewComments(ctx context.Context, cs
 	for _, c := range cs {
 		// get reactions
 		var reactions []*base.Reaction
-		if !g.SkipReactions {
+		if !g.SkipReactions && mayHaveReactions(c.Reactions) {
 			for i := 1; ; i++ {
 				g.waitAndPickClient(ctx)
 				res, resp, err := g.getClient().Reactions.ListPullRequestCommentReactions(ctx, g.repoOwner, g.repoName, c.GetID(), &github.ListReactionOptions{
@@ -783,10 +841,10 @@ func (g *GithubDownloaderV3) convertGithubReviewComments(ctx context.Context, cs
 						PerPage: g.maxPerPage,
 					},
 				})
+				g.setRateFromResponse(resp)
 				if err != nil {
 					return nil, err
 				}
-				g.setRate(&resp.Rate)
 				if len(res) == 0 {
 					break
 				}
@@ -830,10 +888,10 @@ func (g *GithubDownloaderV3) GetReviews(ctx context.Context, reviewable base.Rev
 	for {
 		g.waitAndPickClient(ctx)
 		reviews, resp, err := g.getClient().PullRequests.ListReviews(ctx, g.repoOwner, g.repoName, int(reviewable.GetForeignIndex()), opt)
+		g.setRateFromResponse(resp)
 		if err != nil {
 			return nil, fmt.Errorf("error while listing repos: %w", err)
 		}
-		g.setRate(&resp.Rate)
 		for _, review := range reviews {
 			r := convertGithubReview(review)
 			r.IssueIndex = reviewable.GetLocalIndex()
@@ -844,10 +902,10 @@ func (g *GithubDownloaderV3) GetReviews(ctx context.Context, reviewable base.Rev
 			for {
 				g.waitAndPickClient(ctx)
 				reviewComments, resp, err := g.getClient().PullRequests.ListReviewComments(ctx, g.repoOwner, g.repoName, int(reviewable.GetForeignIndex()), review.GetID(), opt2)
+				g.setRateFromResponse(resp)
 				if err != nil {
 					return nil, fmt.Errorf("error while listing repos: %w", err)
 				}
-				g.setRate(&resp.Rate)
 
 				cs, err := g.convertGithubReviewComments(ctx, reviewComments)
 				if err != nil {
@@ -869,10 +927,10 @@ func (g *GithubDownloaderV3) GetReviews(ctx context.Context, reviewable base.Rev
 	// Get requested reviews
 	g.waitAndPickClient(ctx)
 	reviewers, resp, err := g.getClient().PullRequests.ListReviewers(ctx, g.repoOwner, g.repoName, int(reviewable.GetForeignIndex()))
+	g.setRateFromResponse(resp)
 	if err != nil {
 		return nil, fmt.Errorf("error while listing repos: %w", err)
 	}
-	g.setRate(&resp.Rate)
 	for _, user := range reviewers.Users {
 		r := &base.Review{
 			ReviewerID:   user.GetID(),

services/migrations/github_issue_recovery.go

@@ -0,0 +1,70 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package migrations
+
+import (
+	"context"
+	"fmt"
+
+	base "gitea.dev/modules/migration"
+)
+
+type githubIssueRecoveryUploader struct {
+	base.Uploader
+	downloader *GithubDownloaderV3
+	issues     map[int64]struct{}
+}
+
+func wrapGithubIssueRecoveryUploader(uploader base.Uploader, downloader base.Downloader) base.Uploader {
+	if retry, ok := downloader.(*base.RetryDownloader); ok {
+		downloader = retry.Downloader
+	}
+	github, ok := downloader.(*GithubDownloaderV3)
+	if !ok {
+		return uploader
+	}
+	return &githubIssueRecoveryUploader{
+		Uploader:   uploader,
+		downloader: github,
+		issues:     make(map[int64]struct{}),
+	}
+}
+
+func (g *githubIssueRecoveryUploader) CreateIssues(ctx context.Context, issues ...*base.Issue) error {
+	if err := g.Uploader.CreateIssues(ctx, issues...); err != nil {
+		return err
+	}
+	for _, issue := range issues {
+		g.issues[issue.Number] = struct{}{}
+	}
+	return nil
+}
+
+func (g *githubIssueRecoveryUploader) CreatePullRequests(ctx context.Context, prs ...*base.PullRequest) error {
+	if err := g.Uploader.CreatePullRequests(ctx, prs...); err != nil {
+		return err
+	}
+	for _, pr := range prs {
+		g.issues[pr.Number] = struct{}{}
+	}
+	return nil
+}
+
+func (g *githubIssueRecoveryUploader) CreateComments(ctx context.Context, comments ...*base.Comment) error {
+	for _, comment := range comments {
+		if _, ok := g.issues[comment.IssueIndex]; ok {
+			continue
+		}
+
+		issue, err := g.downloader.GetIssue(ctx, comment.IssueIndex)
+		if err != nil {
+			return fmt.Errorf("recover missing IssueIndex %d: %w", comment.IssueIndex, err)
+		}
+		if err := g.Uploader.CreateIssues(ctx, issue); err != nil {
+			return err
+		}
+		g.issues[issue.Number] = struct{}{}
+	}
+	return g.Uploader.CreateComments(ctx, comments...)
+}

services/migrations/github_test.go

@@ -120,6 +120,57 @@ func TestGithubIssuePagination(t *testing.T) {
 	}
 }
 
+func TestGithubGetAllCommentsSkipsEmptyReactionsAndRecordsRateLimit(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/api/v3/repos/o/r/issues/comments", r.URL.Path)
+		w.Header().Set("Content-Type", "application/json")
+		w.Header().Set("X-RateLimit-Limit", "5000")
+		w.Header().Set("X-RateLimit-Reset", "4102444800")
+		if r.URL.Query().Get("page") == "1" {
+			w.Header().Set("X-RateLimit-Remaining", "100")
+			_, _ = w.Write([]byte(`[{"issue_url":"https://api.github.com/repos/o/r/issues/7","reactions":{"total_count":0}}]`))
+			return
+		}
+
+		w.Header().Set("X-RateLimit-Remaining", "0")
+		w.WriteHeader(http.StatusForbidden)
+	}))
+	defer server.Close()
+
+	downloader, err := NewGithubDownloaderV3(t.Context(), server.URL, "", "", "", "o", "r")
+	require.NoError(t, err)
+	comments, _, err := downloader.GetAllComments(t.Context(), 1, 100)
+	require.NoError(t, err)
+	require.Len(t, comments, 1)
+
+	_, _, err = downloader.GetAllComments(t.Context(), 2, 100)
+	require.Error(t, err)
+	assert.Zero(t, downloader.rates[0].Remaining)
+}
+
+func TestGithubGetIssueRecoversIssueOmittedFromList(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/api/v3/repos/o/r/issues/123":
+			_, _ = w.Write([]byte(`{"number":123,"title":"recovered issue","user":{"id":1,"login":"user"},"created_at":"2024-08-12T08:38:46Z","updated_at":"2025-01-21T10:05:11Z","state":"closed"}`))
+		case "/api/v3/repos/o/r/issues/123/reactions":
+			_, _ = w.Write([]byte(`[]`))
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer server.Close()
+
+	downloader, err := NewGithubDownloaderV3(t.Context(), server.URL, "", "", "", "o", "r")
+	require.NoError(t, err)
+
+	issue, err := downloader.GetIssue(t.Context(), 123)
+	require.NoError(t, err)
+	assert.EqualValues(t, 123, issue.Number)
+	assert.Equal(t, "recovered issue", issue.Title)
+}
+
 func TestGitHubDownloadRepo(t *testing.T) {
 	token := os.Getenv("GITHUB_READ_TOKEN")
 	liveMode := token != ""

services/migrations/migrate.go

@@ -109,7 +109,7 @@ func MigrateRepository(ctx context.Context, doer *user_model.User, ownerName str
 	uploader := NewGiteaLocalUploader(ctx, doer, ownerName, opts.RepoName)
 	uploader.gitServiceType = opts.GitServiceType
 
-	if err := migrateRepository(ctx, doer, downloader, uploader, opts, messenger); err != nil {
+	if err := migrateRepository(ctx, doer, downloader, wrapGithubIssueRecoveryUploader(uploader, downloader), opts, messenger); err != nil {
 		if err1 := uploader.Rollback(); err1 != nil {
 			log.Error("rollback failed: %v", err1)
 		}