diff --git a/models/issues/pull.go b/models/issues/pull.go
index 3707f66bb9a0..0666edc1822b 100644
--- a/models/issues/pull.go
+++ b/models/issues/pull.go
@@ -430,10 +430,11 @@ func (pr *PullRequest) GetGitHeadBranchRefName() string {
 	return fmt.Sprintf("%s%s", git.BranchPrefix, pr.HeadBranch)
 }
 
+// GetReviewCommentsCount returns the number of review comments made on the diff of a PR review (not including comments on commits or issues in a PR)
 func (pr *PullRequest) GetReviewCommentsCount(ctx context.Context) int {
 	opts := FindCommentsOptions{
-		Type:     CommentTypeReview,
-		IssueID:  pr.IssueID,
+		Type:    CommentTypeReview,
+		IssueID: pr.IssueID,
 	}
 	conds := opts.ToConds()
 	if pr.ID == 0 {
diff --git a/modules/structs/pull.go b/modules/structs/pull.go
index f6b498df009c..abf1df36fd3d 100644
--- a/modules/structs/pull.go
+++ b/modules/structs/pull.go
@@ -24,10 +24,11 @@ type PullRequest struct {
 	Draft              bool       `json:"draft"`
 	IsLocked           bool       `json:"is_locked"`
 	Comments           int        `json:"comments"`
-	ReviewComments     int        `json:"review_comments"`
-	Additions          int        `json:"additions"`
-	Deletions          int        `json:"deletions"`
-	ChangedFiles       int        `json:"changed_files"`
+	// number of review comments made on the diff of a PR review (not including comments on commits or issues in a PR)
+	ReviewComments int `json:"review_comments"`
+	Additions      int `json:"additions"`
+	Deletions      int `json:"deletions"`
+	ChangedFiles   int `json:"changed_files"`
 
 	HTMLURL  string `json:"html_url"`
 	DiffURL  string `json:"diff_url"`
diff --git a/services/convert/pull.go b/services/convert/pull.go
index 06d879a6a871..d3679d26a9e3 100644
--- a/services/convert/pull.go
+++ b/services/convert/pull.go
@@ -13,9 +13,7 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
-	"code.gitea.io/gitea/services/gitdiff"
 )
 
 // ToAPIPullRequest assumes following fields have been assigned with valid values:
@@ -203,24 +201,11 @@ func ToAPIPullRequest(ctx context.Context, pr *issues_model.PullRequest, doer *u
 		// Calculate diff
 		startCommitID = pr.MergeBase
 
-		// FIXME: If there are too many files in the repo, may cause some unpredictable issues.
-		diff, err := gitdiff.GetDiff(ctx, gitRepo,
-			&gitdiff.DiffOptions{
-				BeforeCommitID:     startCommitID,
-				AfterCommitID:      endCommitID,
-				MaxLines:           setting.Git.MaxGitDiffLines,
-				MaxLineCharacters:  setting.Git.MaxGitDiffLineCharacters,
-				MaxFiles:           -1, // GetDiff() will return all files
-				WhitespaceBehavior: gitdiff.GetWhitespaceFlag("show-all"),
-			})
+		apiPullRequest.ChangedFiles, apiPullRequest.Additions, apiPullRequest.Deletions, err = gitRepo.GetDiffShortStat(startCommitID, endCommitID)
 		if err != nil {
-			log.Error("GetDiff: %v", err)
+			log.Error("GetDiffShortStat: %v", err)
 			return nil
 		}
-
-		apiPullRequest.Additions = diff.TotalAddition
-		apiPullRequest.Deletions = diff.TotalDeletion
-		apiPullRequest.ChangedFiles = diff.NumFiles
 	}
 
 	if len(apiPullRequest.Head.Sha) == 0 && len(apiPullRequest.Head.Ref) != 0 {