Fix bug when API get pull changed files for deleted head repository (#34333)

routers/api/v1/repo/pull.go

@@ -1638,7 +1638,9 @@ func GetPullRequestFiles(ctx *context.APIContext) {
 
 apiFiles := make([]*api.ChangedFile, 0, limit)
 for i := start; i < start+limit; i++ {
-apiFiles = append(apiFiles, convert.ToChangedFile(diff.Files[i], pr.HeadRepo, endCommitID))
+// refs/pull/1/head stores the HEAD commit ID, allowing all related commits to be found in the base repository.
+// The head repository might have been deleted, so we should not rely on it here.
+apiFiles = append(apiFiles, convert.ToChangedFile(diff.Files[i], pr.BaseRepo, endCommitID))
 }
 
 ctx.SetLinkHeader(totalNumberOfFiles, listOptions.PageSize)

tests/integration/api_pull_test.go

@@ -9,7 +9,10 @@
 "fmt"
 "io"
 "net/http"
+"net/url"
+"strings"
 "testing"
+"time"
 
 auth_model "code.gitea.io/gitea/models/auth"
 "code.gitea.io/gitea/models/db"
@@ -18,11 +21,15 @@
 repo_model "code.gitea.io/gitea/models/repo"
 "code.gitea.io/gitea/models/unittest"
 user_model "code.gitea.io/gitea/models/user"
+"code.gitea.io/gitea/modules/git"
 "code.gitea.io/gitea/modules/setting"
 api "code.gitea.io/gitea/modules/structs"
+"code.gitea.io/gitea/services/convert"
 "code.gitea.io/gitea/services/forms"
 "code.gitea.io/gitea/services/gitdiff"
 issue_service "code.gitea.io/gitea/services/issue"
+pull_service "code.gitea.io/gitea/services/pull"
+files_service "code.gitea.io/gitea/services/repository/files"
 "code.gitea.io/gitea/tests"
 
 "github.com/stretchr/testify/assert"
@@ -425,3 +432,94 @@
 req = NewRequestf(t, "GET", "/api/v1/repos/%s/%s/commits/%s/pull", owner.Name, repo.Name, invalidCommitSHA).AddTokenAuth(ctx.Token)
 ctx.Session.MakeRequest(t, req, http.StatusNotFound)
 }
+
+func TestAPIViewPullFilesWithHeadRepoDeleted(t *testing.T) {
+onGiteaRun(t, func(t *testing.T, u *url.URL) {
+baseRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+
+ctx := NewAPITestContext(t, "user1", baseRepo.Name, auth_model.AccessTokenScopeAll)
+
+doAPIForkRepository(ctx, "user2")(t)
+
+forkedRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ForkID: baseRepo.ID, OwnerName: "user1"})
+
+// add a new file to the forked repo
+addFileToForkedResp, err := files_service.ChangeRepoFiles(git.DefaultContext, forkedRepo, user1, &files_service.ChangeRepoFilesOptions{
+Files: []*files_service.ChangeRepoFile{
+{
+Operation: "create",
+TreePath: "file_1.txt",
+ContentReader: strings.NewReader("file1"),
+},
+},
+Message: "add file1",
+OldBranch: "master",
+NewBranch: "fork-branch-1",
+Author: &files_service.IdentityOptions{
+GitUserName: user1.Name,
+GitUserEmail: user1.Email,
+},
+Committer: &files_service.IdentityOptions{
+GitUserName: user1.Name,
+GitUserEmail: user1.Email,
+},
+Dates: &files_service.CommitDateOptions{
+Author: time.Now(),
+Committer: time.Now(),
+},
+})
+assert.NoError(t, err)
+assert.NotEmpty(t, addFileToForkedResp)
+
+// create Pull
+pullIssue := &issues_model.Issue{
+RepoID: baseRepo.ID,
+Title: "Test pull-request-target-event",
+PosterID: user1.ID,
+Poster: user1,
+IsPull: true,
+}
+pullRequest := &issues_model.PullRequest{
+HeadRepoID: forkedRepo.ID,
+BaseRepoID: baseRepo.ID,
+HeadBranch: "fork-branch-1",
+BaseBranch: "master",
+HeadRepo: forkedRepo,
+BaseRepo: baseRepo,
+Type: issues_model.PullRequestGitea,
+}
+
+prOpts := &pull_service.NewPullRequestOptions{Repo: baseRepo, Issue: pullIssue, PullRequest: pullRequest}
+err = pull_service.NewPullRequest(git.DefaultContext, prOpts)
+assert.NoError(t, err)
+pr := convert.ToAPIPullRequest(t.Context(), pullRequest, user1)
+
+ctx = NewAPITestContext(t, "user2", baseRepo.Name, auth_model.AccessTokenScopeAll)
+doAPIGetPullFiles(ctx, pr, func(t *testing.T, files []*api.ChangedFile) {
+if assert.Len(t, files, 1) {
+assert.Equal(t, "file_1.txt", files[0].Filename)
+assert.Empty(t, files[0].PreviousFilename)
+assert.Equal(t, 1, files[0].Additions)
+assert.Equal(t, 1, files[0].Changes)
+assert.Equal(t, 0, files[0].Deletions)
+assert.Equal(t, "added", files[0].Status)
+}
+})(t)
+
+// delete the head repository of the pull request
+forkCtx := NewAPITestContext(t, "user1", forkedRepo.Name, auth_model.AccessTokenScopeAll)
+doAPIDeleteRepository(forkCtx)(t)
+
+doAPIGetPullFiles(ctx, pr, func(t *testing.T, files []*api.ChangedFile) {
+if assert.Len(t, files, 1) {
+assert.Equal(t, "file_1.txt", files[0].Filename)
+assert.Empty(t, files[0].PreviousFilename)
+assert.Equal(t, 1, files[0].Additions)
+assert.Equal(t, 1, files[0].Changes)
+assert.Equal(t, 0, files[0].Deletions)
+assert.Equal(t, "added", files[0].Status)
+}
+})(t)
+})
+}