feat(diff): Enable commenting on expanded lines in PR diffs

routers/web/repo/compare.go

@@ -14,6 +14,7 @@ import (
 	"net/http"
 	"net/url"
 	"path/filepath"
+	"sort"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
@@ -43,6 +44,7 @@ import (
 	"code.gitea.io/gitea/services/context/upload"
 	"code.gitea.io/gitea/services/gitdiff"
 	pull_service "code.gitea.io/gitea/services/pull"
+	user_service "code.gitea.io/gitea/services/user"
 )
 
 const (
@@ -947,6 +949,69 @@ func ExcerptBlob(ctx *context.Context) {
 			section.Lines = append(section.Lines, lineSection)
 		}
 	}
+	if ctx.Doer != nil {
+		ctx.Data["SignedUserID"] = ctx.Doer.ID
+	}
+	isPull := ctx.FormBool("is_pull")
+	ctx.Data["PageIsPullFiles"] = isPull
+
+	if isPull {
+		if !ctx.Repo.CanRead(unit.TypePullRequests) {
+			ctx.NotFound(nil)
+			return
+		}
+		issueIndex := ctx.FormInt64("issue_index")
+		ctx.Data["IssueIndex"] = issueIndex
+		if issueIndex > 0 {
+			if issue, err := issues_model.GetIssueByIndex(ctx, ctx.Repo.Repository.ID, issueIndex); err == nil && issue.IsPull {
+				ctx.Data["Issue"] = issue
+				ctx.Data["CanBlockUser"] = func(blocker, blockee *user_model.User) bool {
+					return user_service.CanBlockUser(ctx, ctx.Doer, blocker, blockee)
+				}
+
+				if allComments, err := issues_model.FetchCodeComments(ctx, issue, ctx.Doer, ctx.FormBool("show_outdated")); err == nil {
+					if lineComments, ok := allComments[filePath]; ok {
+						for _, line := range section.Lines {
+							if comments, ok := lineComments[int64(line.LeftIdx*-1)]; ok {
+								line.Comments = append(line.Comments, comments...)
+							}
+							if comments, ok := lineComments[int64(line.RightIdx)]; ok {
+								line.Comments = append(line.Comments, comments...)
+							}
+							sort.SliceStable(line.Comments, func(i, j int) bool {
+								return line.Comments[i].CreatedUnix < line.Comments[j].CreatedUnix
+							})
+						}
+
+						// Recalculate hidden comment counts for expand buttons after loading comments
+						for _, line := range section.Lines {
+							if line.Type == gitdiff.DiffLineSection && line.SectionInfo != nil {
+								var hiddenCommentIDs []int64
+								// Check if there are comments in the hidden range
+								for commentLineNum, comments := range lineComments {
+									absLineNum := commentLineNum
+									if absLineNum < 0 {
+										absLineNum = -absLineNum
+									}
+									// Count comments that are in the hidden range
+									if int(absLineNum) > line.SectionInfo.LastRightIdx && int(absLineNum) < line.SectionInfo.RightIdx {
+										// Collect comment IDs
+										for _, comment := range comments {
+											hiddenCommentIDs = append(hiddenCommentIDs, comment.ID)
+										}
+									}
+								}
+								if len(hiddenCommentIDs) > 0 {
+									line.HiddenCommentIDs = hiddenCommentIDs
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+
 	ctx.Data["section"] = section
 	ctx.Data["FileNameHash"] = git.HashFilePathForWebUI(filePath)
 	ctx.Data["AfterCommitID"] = commitID

services/gitdiff/gitdiff.go

@@ -81,13 +81,14 @@ const (
 
 // DiffLine represents a line difference in a DiffSection.
 type DiffLine struct {
-	LeftIdx     int // line number, 1-based
-	RightIdx    int // line number, 1-based
-	Match       int // the diff matched index. -1: no match. 0: plain and no need to match. >0: for add/del, "Lines" slice index of the other side
-	Type        DiffLineType
-	Content     string
-	Comments    issues_model.CommentList // related PR code comments
-	SectionInfo *DiffLineSectionInfo
+	LeftIdx          int // line number, 1-based
+	RightIdx         int // line number, 1-based
+	Match            int // the diff matched index. -1: no match. 0: plain and no need to match. >0: for add/del, "Lines" slice index of the other side
+	Type             DiffLineType
+	Content          string
+	Comments         issues_model.CommentList // related PR code comments
+	SectionInfo      *DiffLineSectionInfo
+	HiddenCommentIDs []int64 // IDs of hidden comments in this section
 }
 
 // DiffLineSectionInfo represents diff line section meta data
@@ -485,6 +486,27 @@ func (diff *Diff) LoadComments(ctx context.Context, issue *issues_model.Issue, c
 					sort.SliceStable(line.Comments, func(i, j int) bool {
 						return line.Comments[i].CreatedUnix < line.Comments[j].CreatedUnix
 					})
+
+					// Mark expand buttons that have comments in hidden lines
+					if line.Type == DiffLineSection && line.SectionInfo != nil {
+						var hiddenCommentIDs []int64
+						// Check if there are comments in the hidden range
+						for commentLineNum, comments := range lineCommits {
+							absLineNum := int(commentLineNum)
+							if commentLineNum < 0 {
+								absLineNum = int(-commentLineNum)
+							}
+							if absLineNum > line.SectionInfo.LastRightIdx && absLineNum < line.SectionInfo.RightIdx {
+								// Collect comment IDs
+								for _, comment := range comments {
+									hiddenCommentIDs = append(hiddenCommentIDs, comment.ID)
+								}
+							}
+						}
+						if len(hiddenCommentIDs) > 0 {
+							line.HiddenCommentIDs = hiddenCommentIDs
+						}
+					}
 				}
 			}
 		}
@@ -1386,6 +1408,70 @@ func CommentAsDiff(ctx context.Context, c *issues_model.Comment) (*Diff, error)
 	return diff, nil
 }
 
+// GeneratePatchForUnchangedLine creates a patch showing code context for an unchanged line
+func GeneratePatchForUnchangedLine(gitRepo *git.Repository, commitID, treePath string, line int64, contextLines int) (string, error) {
+	commit, err := gitRepo.GetCommit(commitID)
+	if err != nil {
+		return "", fmt.Errorf("GetCommit: %w", err)
+	}
+
+	entry, err := commit.GetTreeEntryByPath(treePath)
+	if err != nil {
+		return "", fmt.Errorf("GetTreeEntryByPath: %w", err)
+	}
+
+	blob := entry.Blob()
+	dataRc, err := blob.DataAsync()
+	if err != nil {
+		return "", fmt.Errorf("DataAsync: %w", err)
+	}
+	defer dataRc.Close()
+
+	// Calculate line range (commented line + lines above it)
+	commentLine := int(line)
+	if line < 0 {
+		commentLine = int(-line)
+	}
+	startLine := max(commentLine-contextLines, 1)
+	endLine := commentLine
+
+	// Read only the needed lines efficiently
+	scanner := bufio.NewScanner(dataRc)
+	currentLine := 0
+	var lines []string
+	for scanner.Scan() {
+		currentLine++
+		if currentLine >= startLine && currentLine <= endLine {
+			lines = append(lines, scanner.Text())
+		}
+		if currentLine > endLine {
+			break
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return "", fmt.Errorf("scanner error: %w", err)
+	}
+
+	if len(lines) == 0 {
+		return "", fmt.Errorf("no lines found in range %d-%d", startLine, endLine)
+	}
+
+	// Generate synthetic patch
+	var patchBuilder strings.Builder
+	patchBuilder.WriteString(fmt.Sprintf("diff --git a/%s b/%s\n", treePath, treePath))
+	patchBuilder.WriteString(fmt.Sprintf("--- a/%s\n", treePath))
+	patchBuilder.WriteString(fmt.Sprintf("+++ b/%s\n", treePath))
+	patchBuilder.WriteString(fmt.Sprintf("@@ -%d,%d +%d,%d @@\n", startLine, len(lines), startLine, len(lines)))
+
+	for _, lineContent := range lines {
+		patchBuilder.WriteString(" ")
+		patchBuilder.WriteString(lineContent)
+		patchBuilder.WriteString("\n")
+	}
+
+	return patchBuilder.String(), nil
+}
+
 // CommentMustAsDiff executes AsDiff and logs the error instead of returning
 func CommentMustAsDiff(ctx context.Context, c *issues_model.Comment) *Diff {
 	if c == nil {

services/pull/review.go

@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/modules/optional"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/services/gitdiff"
 	notify_service "code.gitea.io/gitea/services/notify"
 )
 
@@ -283,6 +284,16 @@ func createCodeComment(ctx context.Context, doer *user_model.User, repo *repo_mo
 			log.Error("Error whilst generating patch: %v", err)
 			return nil, err
 		}
+
+		// If patch is still empty (unchanged line), generate code context
+		if len(patch) == 0 && len(commitID) > 0 {
+			patch, err = gitdiff.GeneratePatchForUnchangedLine(gitRepo, commitID, treePath, line, setting.UI.CodeCommentLines)
+			if err != nil {
+				// Log the error but don't fail comment creation
+				// This can happen for deleted/renamed files or other edge cases
+				log.Warn("Unable to generate patch for unchanged line (file=%s, line=%d, commit=%s): %v", treePath, line, commitID, err)
+			}
+		}
 	}
 	return issues_model.CreateComment(ctx, &issues_model.CreateCommentOptions{
 		Type:        issues_model.CommentTypeCode,

templates/repo/diff/blob_excerpt.tmpl

@@ -1,24 +1,27 @@
-{{$blobExcerptLink := print $.RepoLink (Iif $.PageIsWiki "/wiki" "") "/blob_excerpt/" (PathEscape $.AfterCommitID) (QueryBuild "?" "anchor" $.Anchor)}}
+{{$blobExcerptLink := print $.RepoLink (Iif $.PageIsWiki "/wiki" "") "/blob_excerpt/" (PathEscape $.AfterCommitID) (QueryBuild "?" "anchor" $.Anchor) (Iif $.PageIsPullFiles (print "&is_pull=true&issue_index=" $.IssueIndex) "")}}
 {{if $.IsSplitStyle}}
 	{{range $k, $line := $.section.Lines}}
-	<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}} line-expanded">
+	<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}} line-expanded" data-line-type="{{.GetHTMLDiffLineType}}">
 		{{if eq .GetType 4}}
 			{{$expandDirection := $line.GetExpandDirection}}
 			<td class="lines-num lines-num-old" data-line-num="{{if $line.LeftIdx}}{{$line.LeftIdx}}{{end}}">
 				<div class="code-expander-buttons" data-expand-direction="{{$expandDirection}}">
 				{{if or (eq $expandDirection 3) (eq $expandDirection 5)}}
-					<button class="code-expander-button" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=split&direction=down">
+					<button class="code-expander-button{{if $line.HiddenCommentIDs}} has-hidden-comments{{end}}" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=split&direction=down" title="{{if $line.HiddenCommentIDs}}{{len $line.HiddenCommentIDs}} hidden comment(s){{end}}">
 						{{svg "octicon-fold-down"}}
+						{{if $line.HiddenCommentIDs}}<span class="ui mini label">{{len $line.HiddenCommentIDs}}</span>{{end}}
 					</button>
 				{{end}}
 				{{if or (eq $expandDirection 3) (eq $expandDirection 4)}}
-					<button class="code-expander-button" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=split&direction=up">
+					<button class="code-expander-button{{if $line.HiddenCommentIDs}} has-hidden-comments{{end}}" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=split&direction=up" title="{{if $line.HiddenCommentIDs}}{{len $line.HiddenCommentIDs}} hidden comment(s){{end}}">
 						{{svg "octicon-fold-up"}}
+						{{if $line.HiddenCommentIDs}}<span class="ui mini label">{{len $line.HiddenCommentIDs}}</span>{{end}}
 					</button>
 				{{end}}
 				{{if eq $expandDirection 2}}
-					<button class="code-expander-button" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=split">
+					<button class="code-expander-button{{if $line.HiddenCommentIDs}} has-hidden-comments{{end}}" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=split" title="{{if $line.HiddenCommentIDs}}{{len $line.HiddenCommentIDs}} hidden comment(s){{end}}">
 						{{svg "octicon-fold"}}
+						{{if $line.HiddenCommentIDs}}<span class="ui mini label">{{len $line.HiddenCommentIDs}}</span>{{end}}
 					</button>
 				{{end}}
 				</div>
@@ -33,6 +36,11 @@
 			<td class="lines-escape lines-escape-old">{{if and $line.LeftIdx $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button btn interact-bg" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff}}"></button>{{end}}</td>
 			<td class="lines-type-marker lines-type-marker-old">{{if $line.LeftIdx}}<span class="tw-font-mono" data-type-marker=""></span>{{end}}</td>
 			<td class="lines-code lines-code-old">
+				{{- if and $.SignedUserID $.PageIsPullFiles $line.LeftIdx -}}
+					<button type="button" aria-label="{{ctx.Locale.Tr "repo.diff.comment.add_line_comment"}}" class="ui primary button add-code-comment add-code-comment-left{{if (not $line.CanComment)}} tw-invisible{{end}}" data-side="left" data-idx="{{$line.LeftIdx}}">
+						{{- svg "octicon-plus" -}}
+					</button>
+				{{- end -}}
 				{{- if $line.LeftIdx -}}
 					{{- template "repo/diff/section_code" dict "diff" $inlineDiff -}}
 				{{- else -}}
@@ -43,6 +51,11 @@
 			<td class="lines-escape lines-escape-new">{{if and $line.RightIdx $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button btn interact-bg" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff}}"></button>{{end}}</td>
 			<td class="lines-type-marker lines-type-marker-new">{{if $line.RightIdx}}<span class="tw-font-mono" data-type-marker=""></span>{{end}}</td>
 			<td class="lines-code lines-code-new">
+				{{- if and $.SignedUserID $.PageIsPullFiles $line.RightIdx -}}
+					<button type="button" aria-label="{{ctx.Locale.Tr "repo.diff.comment.add_line_comment"}}" class="ui primary button add-code-comment add-code-comment-right{{if (not $line.CanComment)}} tw-invisible{{end}}" data-side="right" data-idx="{{$line.RightIdx}}">
+						{{- svg "octicon-plus" -}}
+					</button>
+				{{- end -}}
 				{{- if $line.RightIdx -}}
 					{{- template "repo/diff/section_code" dict "diff" $inlineDiff -}}
 				{{- else -}}
@@ -51,27 +64,44 @@
 			</td>
 		{{end}}
 	</tr>
+	{{if $line.Comments}}
+		<tr class="add-comment" data-line-type="{{.GetHTMLDiffLineType}}">
+			<td class="add-comment-left" colspan="4">
+				{{if eq $line.GetCommentSide "previous"}}
+					{{template "repo/diff/conversation" dict "." $ "comments" $line.Comments}}
+				{{end}}
+			</td>
+			<td class="add-comment-right" colspan="4">
+				{{if eq $line.GetCommentSide "proposed"}}
+					{{template "repo/diff/conversation" dict "." $ "comments" $line.Comments}}
+				{{end}}
+			</td>
+		</tr>
+	{{end}}
 	{{end}}
 {{else}}
 	{{range $k, $line := $.section.Lines}}
-	<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}} line-expanded">
+	<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}} line-expanded" data-line-type="{{.GetHTMLDiffLineType}}">
 		{{if eq .GetType 4}}
 			{{$expandDirection := $line.GetExpandDirection}}
 			<td colspan="2" class="lines-num">
 				<div class="code-expander-buttons" data-expand-direction="{{$expandDirection}}">
 					{{if or (eq $expandDirection 3) (eq $expandDirection 5)}}
-						<button class="code-expander-button" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=unified&direction=down">
+						<button class="code-expander-button{{if $line.HiddenCommentIDs}} has-hidden-comments{{end}}" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=unified&direction=down" title="{{if $line.HiddenCommentIDs}}{{len $line.HiddenCommentIDs}} hidden comment(s){{end}}"{{if $line.HiddenCommentIDs}} data-hidden-comment-ids="{{StringUtils.ToString $line.HiddenCommentIDs}}"{{end}}>
 							{{svg "octicon-fold-down"}}
+							{{if $line.HiddenCommentIDs}}<span class="ui mini label">{{len $line.HiddenCommentIDs}}</span>{{end}}
 						</button>
 					{{end}}
 					{{if or (eq $expandDirection 3) (eq $expandDirection 4)}}
-						<button class="code-expander-button" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=unified&direction=up">
+						<button class="code-expander-button{{if $line.HiddenCommentIDs}} has-hidden-comments{{end}}" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=unified&direction=up" title="{{if $line.HiddenCommentIDs}}{{len $line.HiddenCommentIDs}} hidden comment(s){{end}}"{{if $line.HiddenCommentIDs}} data-hidden-comment-ids="{{StringUtils.ToString $line.HiddenCommentIDs}}"{{end}}>
 							{{svg "octicon-fold-up"}}
+							{{if $line.HiddenCommentIDs}}<span class="ui mini label">{{len $line.HiddenCommentIDs}}</span>{{end}}
 						</button>
 					{{end}}
 					{{if eq $expandDirection 2}}
-						<button class="code-expander-button" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=unified">
+						<button class="code-expander-button{{if $line.HiddenCommentIDs}} has-hidden-comments{{end}}" hx-target="closest tr" hx-get="{{$blobExcerptLink}}&{{$line.GetBlobExcerptQuery}}&style=unified" title="{{if $line.HiddenCommentIDs}}{{len $line.HiddenCommentIDs}} hidden comment(s){{end}}"{{if $line.HiddenCommentIDs}} data-hidden-comment-ids="{{StringUtils.ToString $line.HiddenCommentIDs}}"{{end}}>
 							{{svg "octicon-fold"}}
+							{{if $line.HiddenCommentIDs}}<span class="ui mini label">{{len $line.HiddenCommentIDs}}</span>{{end}}
 						</button>
 					{{end}}
 				</div>
@@ -83,7 +113,21 @@
 		{{$inlineDiff := $.section.GetComputedInlineDiffFor $line ctx.Locale}}
 		<td class="lines-escape">{{if $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button btn interact-bg" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff}}"></button>{{end}}</td>
 		<td class="lines-type-marker"><span class="tw-font-mono" data-type-marker="{{$line.GetLineTypeMarker}}"></span></td>
-		<td class="lines-code{{if (not $line.RightIdx)}} lines-code-old{{end}}"><code {{if $inlineDiff.EscapeStatus.Escaped}}class="code-inner has-escaped" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff}}"{{else}}class="code-inner"{{end}}>{{$inlineDiff.Content}}</code></td>
+		<td class="lines-code{{if (not $line.RightIdx)}} lines-code-old{{end}}">
+			{{- if and $.SignedUserID $.PageIsPullFiles -}}
+				<button type="button" aria-label="{{ctx.Locale.Tr "repo.diff.comment.add_line_comment"}}" class="ui primary button add-code-comment add-code-comment-{{if $line.RightIdx}}right{{else}}left{{end}}{{if (not $line.CanComment)}} tw-invisible{{end}}" data-side="{{if $line.RightIdx}}right{{else}}left{{end}}" data-idx="{{if $line.RightIdx}}{{$line.RightIdx}}{{else}}{{$line.LeftIdx}}{{end}}">
+					{{- svg "octicon-plus" -}}
+				</button>
+			{{- end -}}
+			<code {{if $inlineDiff.EscapeStatus.Escaped}}class="code-inner has-escaped" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff}}"{{else}}class="code-inner"{{end}}>{{$inlineDiff.Content}}</code>
+		</td>
 	</tr>
+	{{if $line.Comments}}
+		<tr class="add-comment" data-line-type="{{.GetHTMLDiffLineType}}">
+			<td class="add-comment-left add-comment-right" colspan="5">
+				{{template "repo/diff/conversation" dict "." $ "comments" $line.Comments}}
+			</td>
+		</tr>
+	{{end}}
 	{{end}}
 {{end}}