feat(repo): add co-author parsing and avatar components

Extract and harden co-author trailer parsing, add reusable co-author avatar templates, and wire commit/repo views to render co-author metadata.

models/user/user.go

@@ -1140,9 +1140,16 @@ func GetUsersBySource(ctx context.Context, s *auth.Source) ([]*User, error) {
 	return users, err
 }
 
+// CoAuthorUser represents a co-author parsed from a commit trailer, with optional Gitea user.
+type CoAuthorUser struct {
+	GiteaUser        *User
+	TrailerSignature *git.Signature
+}
+
 // UserCommit represents a commit with validation of user.
 type UserCommit struct { //revive:disable-line:exported
-	User *User
+	User      *User
+	CoAuthors []*CoAuthorUser
 	*git.Commit
 }
 
@@ -1158,6 +1165,27 @@ func ValidateCommitWithEmail(ctx context.Context, c *git.Commit) *User {
 	return u
 }
 
+// CoAuthorsFromCommit resolves co-author signatures from a commit into CoAuthorUser values.
+func CoAuthorsFromCommit(ctx context.Context, c *git.Commit) ([]*CoAuthorUser, error) {
+	sigs := c.CoAuthorSignatures()
+	if len(sigs) == 0 {
+		return nil, nil
+	}
+	emails := make([]string, len(sigs))
+	for i, sig := range sigs {
+		emails[i] = sig.Email
+	}
+	emailUserMap, err := GetUsersByEmails(ctx, emails)
+	if err != nil {
+		return nil, err
+	}
+	coAuthors := make([]*CoAuthorUser, len(sigs))
+	for i, sig := range sigs {
+		coAuthors[i] = &CoAuthorUser{GiteaUser: emailUserMap.GetByEmail(sig.Email), TrailerSignature: sig}
+	}
+	return coAuthors, nil
+}
+
 // ValidateCommitsWithEmails checks if authors' e-mails of commits are corresponding to users.
 func ValidateCommitsWithEmails(ctx context.Context, oldCommits []*git.Commit) ([]*UserCommit, error) {
 	var (
@@ -1168,6 +1196,9 @@ func ValidateCommitsWithEmails(ctx context.Context, oldCommits []*git.Commit) ([
 		if c.Author != nil {
 			emailSet.Add(c.Author.Email)
 		}
+		for _, sig := range c.CoAuthorSignatures() {
+			emailSet.Add(sig.Email)
+		}
 	}
 
 	emailUserMap, err := GetUsersByEmails(ctx, emailSet.Values())
@@ -1177,9 +1208,18 @@ func ValidateCommitsWithEmails(ctx context.Context, oldCommits []*git.Commit) ([
 
 	for _, c := range oldCommits {
 		user := emailUserMap.GetByEmail(c.Author.Email) // FIXME: why ValidateCommitsWithEmails uses "Author", but ParseCommitsWithSignature uses "Committer"?
+		coAuthorSigs := c.CoAuthorSignatures()
+		coAuthors := make([]*CoAuthorUser, 0, len(coAuthorSigs))
+		for _, sig := range coAuthorSigs {
+			coAuthors = append(coAuthors, &CoAuthorUser{
+				GiteaUser:        emailUserMap.GetByEmail(sig.Email),
+				TrailerSignature: sig,
+			})
+		}
 		newCommits = append(newCommits, &UserCommit{
-			User:   user,
-			Commit: c,
+			User:      user,
+			CoAuthors: coAuthors,
+			Commit:    c,
 		})
 	}
 	return newCommits, nil

modules/git/commit.go

@@ -17,10 +17,11 @@ import (
 )
 
 type CommitMessage struct {
-	MessageRaw   string
-	messageUTF8  *string
-	messageTitle *string
-	messageBody  *string
+	MessageRaw       string
+	messageUTF8      *string
+	messageTitle     *string
+	messageBody      *string
+	messageCoAuthors *[]*Signature
 }
 
 // Commit represents a git commit.
@@ -68,6 +69,50 @@ func (c *CommitMessage) MessageBody() string {
 	return *c.messageBody
 }
 
+// CoAuthorSignatures parses "Co-authored-by:" and "Co-committed-by:" trailers
+// from the trailing block of the commit message and returns deduplicated
+// Signature values. Only the last paragraph of the body is scanned so that
+// quoted or in-body occurrences (e.g. inside a revert/cherry-pick description)
+// are not misinterpreted as trailers, matching `git interpret-trailers`.
+func (c *CommitMessage) CoAuthorSignatures() []*Signature {
+	if c.messageCoAuthors != nil {
+		return *c.messageCoAuthors
+	}
+	var sigs []*Signature
+	seen := make(map[string]struct{})
+	body := strings.TrimRight(c.MessageBody(), "\n")
+	if idx := strings.LastIndex(body, "\n\n"); idx >= 0 {
+		body = body[idx+2:]
+	}
+	for line := range strings.SplitSeq(body, "\n") {
+		var rest string
+		var ok bool
+		if rest, ok = strings.CutPrefix(line, "Co-authored-by:"); !ok {
+			rest, ok = strings.CutPrefix(line, "Co-committed-by:")
+			if !ok {
+				continue
+			}
+		}
+		rest = strings.TrimSpace(rest)
+		name, emailWithBracket, ok := strings.Cut(rest, " <")
+		if !ok {
+			continue
+		}
+		email, _, ok := strings.Cut(emailWithBracket, ">")
+		if !ok {
+			continue
+		}
+		email = strings.ToLower(strings.TrimSpace(email))
+		if _, exists := seen[email]; exists {
+			continue
+		}
+		seen[email] = struct{}{}
+		sigs = append(sigs, &Signature{Name: strings.TrimSpace(name), Email: email})
+	}
+	c.messageCoAuthors = &sigs
+	return sigs
+}
+
 // ParentID returns oid of n-th parent (0-based index).
 // It returns nil if no such parent exists.
 func (c *Commit) ParentID(n int) (ObjectID, error) {

options/locale/locale_en-US.json

@@ -2589,6 +2589,10 @@
   "repo.diff.review.reject": "Request changes",
   "repo.diff.review.self_approve": "Pull request authors can't approve their own pull request",
   "repo.diff.committed_by": "committed by",
+  "repo.diff.coauthored_by": "co-authored by",
+  "repo.commits.coauthor_and": "and",
+  "repo.commits.coauthor_others_1": "%d other",
+  "repo.commits.coauthor_others_n": "%d others",
   "repo.diff.protected": "Protected",
   "repo.diff.image.side_by_side": "Side by Side",
   "repo.diff.image.swipe": "Swipe",

routers/web/repo/commit.go

@@ -382,6 +382,11 @@ func Diff(ctx *context.Context) {
 	verification := asymkey_service.ParseCommitWithSignature(ctx, commit)
 	ctx.Data["Verification"] = verification
 	ctx.Data["Author"] = user_model.ValidateCommitWithEmail(ctx, commit)
+	if coAuthors, err := user_model.CoAuthorsFromCommit(ctx, commit); err != nil {
+		log.Error("CoAuthorsFromCommit: %v", err)
+	} else {
+		ctx.Data["CoAuthors"] = coAuthors
+	}
 	ctx.Data["Parents"] = parents
 	ctx.Data["DiffNotAvailable"] = diffShortStat.NumFiles == 0
 

routers/web/repo/view.go

@@ -135,6 +135,12 @@ func loadLatestCommitData(ctx *context.Context, latestCommit *git.Commit) bool {
 		ctx.Data["LatestCommitVerification"] = verification
 		ctx.Data["LatestCommitUser"] = user_model.ValidateCommitWithEmail(ctx, latestCommit)
 
+		if coAuthors, err := user_model.CoAuthorsFromCommit(ctx, latestCommit); err != nil {
+			log.Error("CoAuthorsFromCommit: %v", err)
+		} else {
+			ctx.Data["LatestCommitCoAuthors"] = coAuthors
+		}
+
 		statuses, err := git_model.GetLatestCommitStatus(ctx, ctx.Repo.Repository.ID, latestCommit.ID.String(), db.ListOptionsAll)
 		if err != nil {
 			log.Error("GetLatestCommitStatus: %v", err)

templates/repo/commit_coauthor_avatar_stack.tmpl

@@ -0,0 +1,49 @@
+{{if or .CoAuthors .CoAuthorSignatures}}
+	{{- $additionalClasses := .AdditionalClasses -}}
+	<span class="coauthor-avatar-stack {{$additionalClasses}}">
+		{{- if .AuthorUser -}}
+			<a href="{{.AuthorUser.HomeLink}}" data-tooltip-content="{{.AuthorUser.GetDisplayName}}">{{- ctx.AvatarUtils.Avatar .AuthorUser 20 -}}</a>
+		{{- else -}}
+			{{- ctx.AvatarUtils.AvatarByEmail .AuthorSignature.Email .AuthorSignature.Name 20 -}}
+		{{- end -}}
+		{{- if .CoAuthors -}}
+			{{- $coCount := len .CoAuthors -}}
+			{{- $maxCo := 9 -}}
+			{{- $visibleCo := .CoAuthors -}}
+			{{- $overflow := 0 -}}
+			{{- if gt $coCount $maxCo -}}
+				{{- $visibleCo = slice .CoAuthors 0 $maxCo -}}
+				{{- $overflow = Eval $coCount "-" $maxCo -}}
+			{{- end -}}
+			{{- range $visibleCo -}}
+				{{- if .GiteaUser -}}
+					<a href="{{.GiteaUser.HomeLink}}" data-tooltip-content="{{.GiteaUser.GetDisplayName}}">{{- ctx.AvatarUtils.Avatar .GiteaUser 20 -}}</a>
+				{{- else -}}
+					{{- ctx.AvatarUtils.AvatarByEmail .TrailerSignature.Email .TrailerSignature.Name 20 -}}
+				{{- end -}}
+			{{- end -}}
+			{{- if gt $overflow 0 -}}
+				<span class="coauthor-overflow-chip" data-tooltip-content="{{ctx.Locale.TrN $overflow "repo.commits.coauthor_others_1" "repo.commits.coauthor_others_n" $overflow}}">+{{$overflow}}</span>
+			{{- end -}}
+		{{- else -}}
+			{{- $coCount := len .CoAuthorSignatures -}}
+			{{- $maxCo := 9 -}}
+			{{- $visibleCo := .CoAuthorSignatures -}}
+			{{- $overflow := 0 -}}
+			{{- if gt $coCount $maxCo -}}
+				{{- $visibleCo = slice .CoAuthorSignatures 0 $maxCo -}}
+				{{- $overflow = Eval $coCount "-" $maxCo -}}
+			{{- end -}}
+			{{- range $visibleCo -}}
+				{{- ctx.AvatarUtils.AvatarByEmail .Email .Name 20 -}}
+			{{- end -}}
+			{{- if gt $overflow 0 -}}
+				<span class="coauthor-overflow-chip" data-tooltip-content="{{ctx.Locale.TrN $overflow "repo.commits.coauthor_others_1" "repo.commits.coauthor_others_n" $overflow}}">+{{$overflow}}</span>
+			{{- end -}}
+		{{- end -}}
+	</span>
+{{else if .AuthorUser}}
+	{{- ctx.AvatarUtils.Avatar .AuthorUser 20 .AdditionalClasses -}}
+{{else}}
+	{{- ctx.AvatarUtils.AvatarByEmail .AuthorSignature.Email .AuthorSignature.Name 20 .AdditionalClasses -}}
+{{end}}

templates/repo/commit_coauthor_avatars.tmpl

@@ -0,0 +1,43 @@
+{{/*
+	Renders the author/co-author avatar stack and name text for a commit.
+	Args (via dict):
+		AuthorUser       - *user_model.User (may be nil if no Gitea account)
+		AuthorSignature  - *git.Signature   (always set: name + email from git)
+		CoAuthors        - []*user_model.CoAuthorUser
+		fields: GiteaUser (*User, may be nil), TrailerSignature (*git.Signature)
+
+	Avatar stack is capped at 10 children (author + up to 9 co-authors); any
+	remainder is collapsed into a trailing "+N" chip. The .coauthor-avatar-stack
+	CSS rules expect at most 10 children to fan out cleanly on hover.
+*/}}
+<span class="author-wrapper">
+{{- if .CoAuthors -}}
+	{{- $coCount := len .CoAuthors -}}
+	{{template "repo/commit_coauthor_avatar_stack" dict "AuthorUser" .AuthorUser "AuthorSignature" .AuthorSignature "CoAuthors" .CoAuthors}}
+	{{- if .AuthorUser -}}
+		{{- .AuthorUser.GetShortDisplayNameLinkHTML -}}
+	{{- else -}}
+		{{.AuthorSignature.Name}}
+	{{- end -}}
+	{{" "}}{{ctx.Locale.Tr "repo.commits.coauthor_and"}}{{" "}}
+	{{- if eq $coCount 1 -}}
+		{{- with index .CoAuthors 0 -}}
+			{{- if .GiteaUser -}}
+				<a class="muted" href="{{.GiteaUser.HomeLink}}">{{.GiteaUser.GetDisplayName}}</a>
+			{{- else -}}
+				{{.TrailerSignature.Name}}
+			{{- end -}}
+		{{- end -}}
+	{{- else -}}
+		{{- ctx.Locale.TrN $coCount "repo.commits.coauthor_others_1" "repo.commits.coauthor_others_n" $coCount -}}
+	{{- end -}}
+{{- else -}}
+	{{- if .AuthorUser -}}
+		{{- template "repo/commit_coauthor_avatar_stack" dict "AuthorUser" .AuthorUser "AuthorSignature" .AuthorSignature "AdditionalClasses" "tw-mr-1" -}}
+		{{- .AuthorUser.GetShortDisplayNameLinkHTML -}}
+	{{- else -}}
+		{{- template "repo/commit_coauthor_avatar_stack" dict "AuthorSignature" .AuthorSignature "AdditionalClasses" "tw-mr-1" -}}
+		{{.AuthorSignature.Name}}
+	{{- end -}}
+{{- end -}}
+</span>

templates/repo/commit_page.tmpl

@@ -155,6 +155,21 @@
 				{{end}}
 			</div>
 
+			{{if .CoAuthors}}
+				<div class="flex-text-inline">
+					<span class="tw-text-text-light">{{ctx.Locale.Tr "repo.diff.coauthored_by"}}</span>
+					{{range .CoAuthors}}
+						{{if .GiteaUser}}
+							{{ctx.AvatarUtils.Avatar .GiteaUser 20}}
+							<a href="{{.GiteaUser.HomeLink}}"><strong>{{.GiteaUser.GetDisplayName}}</strong></a>
+						{{else}}
+							{{ctx.AvatarUtils.AvatarByEmail .TrailerSignature.Email .TrailerSignature.Name 20}}
+							<strong>{{.TrailerSignature.Name}}</strong>
+						{{end}}
+					{{end}}
+				</div>
+			{{end}}
+
 			{{if .Verification}}
 				{{template "repo/commit_sign_badge" dict "CommitSignVerification" .Verification}}
 			{{end}}

templates/repo/commits_list.tmpl

@@ -2,9 +2,9 @@
 	<table class="ui very basic table unstackable" id="commits-table">
 		<thead>
 			<tr>
-				<th class="three wide">{{ctx.Locale.Tr "repo.commits.author"}}</th>
+				<th class="four wide">{{ctx.Locale.Tr "repo.commits.author"}}</th>
 				<th class="two wide sha">{{StringUtils.ToUpper $.Repository.ObjectFormatName}}</th>
-				<th class="eight wide message">{{ctx.Locale.Tr "repo.commits.message"}}</th>
+				<th class="seven wide message">{{ctx.Locale.Tr "repo.commits.message"}}</th>
 				<th class="two wide tw-text-right">{{ctx.Locale.Tr "repo.commits.date"}}</th>
 				<th class="one wide"></th>
 			</tr>
@@ -14,15 +14,7 @@
 			{{range $commit := .Commits}}
 				<tr>
 					<td class="author">
-						<span class="author-wrapper">
-							{{- if .User -}}
-								{{- ctx.AvatarUtils.Avatar .User 20 "tw-mr-2" -}}
-								{{- .User.GetShortDisplayNameLinkHTML -}}
-							{{- else -}}
-								{{- ctx.AvatarUtils.AvatarByEmail .Author.Email .Author.Name 20 "tw-mr-2" -}}
-								{{- .Author.Name -}}
-							{{- end -}}
-						</span>
+						{{template "repo/commit_coauthor_avatars" dict "AuthorUser" .User "AuthorSignature" .Author "CoAuthors" .CoAuthors}}
 					</td>
 					<td class="sha">
 						{{$commitBaseLink := ""}}

templates/repo/latest_commit.tmpl

@@ -2,15 +2,7 @@
 {{if not .LatestCommit}}
 	…
 {{else}}
-	<span class="author-wrapper">
-	{{- if .LatestCommitUser -}}
-		{{- ctx.AvatarUtils.Avatar .LatestCommitUser 20 "tw-mr-2" -}}
-		<strong>{{.LatestCommitUser.GetShortDisplayNameLinkHTML}}</strong>
-	{{- else if .LatestCommit.Author -}}
-		{{- ctx.AvatarUtils.AvatarByEmail .LatestCommit.Author.Email .LatestCommit.Author.Name 20 "tw-mr-2" -}}
-		<strong>{{.LatestCommit.Author.Name}}</strong>
-	{{- end -}}
-	</span>
+	{{template "repo/commit_coauthor_avatars" dict "AuthorUser" .LatestCommitUser "AuthorSignature" .LatestCommit.Author "CoAuthors" .LatestCommitCoAuthors}}
 
 	{{template "repo/commit_sign_badge" dict "Commit" .LatestCommit "CommitBaseLink" (print .RepoLink "/commit") "CommitSignVerification" .LatestCommitVerification}}
 

web_src/css/repo.css

@@ -1403,11 +1403,72 @@ tbody.commit-list {
 }
 
 .author-wrapper {
-  max-width: 180px;
+  max-width: 240px;
   align-self: center;
   white-space: nowrap;
 }
 
+.coauthor-avatar-stack {
+  display: inline-flex;
+  align-items: center;
+  vertical-align: middle;
+  margin-right: 0.25rem;
+}
+
+/* each direct child of the stack is either <a> (linked user) or <img> (no account) */
+.coauthor-avatar-stack > * {
+  margin-left: -12px;
+  transition: transform 0.15s ease;
+  position: relative;
+  z-index: 0;
+  display: inline-flex;
+  border-radius: 50%;
+}
+
+.coauthor-avatar-stack > *:first-child {
+  margin-left: 0;
+}
+
+.coauthor-avatar-stack .avatar {
+  border: 2px solid var(--color-body);
+  border-radius: 50%;
+}
+
+.coauthor-overflow-chip {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 20px;
+  height: 20px;
+  font-size: 10px;
+  font-weight: var(--font-weight-semibold);
+  border: 2px solid var(--color-body);
+  border-radius: 50%;
+  background: var(--color-secondary);
+  color: var(--color-text);
+}
+
+.coauthor-avatar-stack > *:nth-child(1) { z-index: 20; }
+.coauthor-avatar-stack > *:nth-child(2) { z-index: 19; }
+.coauthor-avatar-stack > *:nth-child(3) { z-index: 18; }
+.coauthor-avatar-stack > *:nth-child(4) { z-index: 17; }
+.coauthor-avatar-stack > *:nth-child(5) { z-index: 16; }
+.coauthor-avatar-stack > *:nth-child(6) { z-index: 15; }
+.coauthor-avatar-stack > *:nth-child(7) { z-index: 14; }
+.coauthor-avatar-stack > *:nth-child(8) { z-index: 13; }
+.coauthor-avatar-stack > *:nth-child(9) { z-index: 12; }
+.coauthor-avatar-stack > *:nth-child(10) { z-index: 11; }
+
+.coauthor-avatar-stack:hover > *:nth-child(2) { transform: translateX(12px); }
+.coauthor-avatar-stack:hover > *:nth-child(3) { transform: translateX(24px); }
+.coauthor-avatar-stack:hover > *:nth-child(4) { transform: translateX(36px); }
+.coauthor-avatar-stack:hover > *:nth-child(5) { transform: translateX(48px); }
+.coauthor-avatar-stack:hover > *:nth-child(6) { transform: translateX(60px); }
+.coauthor-avatar-stack:hover > *:nth-child(7) { transform: translateX(72px); }
+.coauthor-avatar-stack:hover > *:nth-child(8) { transform: translateX(84px); }
+.coauthor-avatar-stack:hover > *:nth-child(9) { transform: translateX(96px); }
+.coauthor-avatar-stack:hover > *:nth-child(10) { transform: translateX(108px); }
+
 .latest-commit .message-wrapper {
   max-width: calc(100% - 2.5rem);
 }