Use relative links for commits, mentions, and issues in markdown (#29427)

Fixes #29404

Use relative links for
- commits
- mentions
- issues

---------

Co-authored-by: silverwind <me@silverwind.io>

modules/markup/html.go

@@ -609,7 +609,7 @@ func mentionProcessor(ctx *RenderContext, node *html.Node) {
 		if ok && strings.Contains(mention, "/") {
 			mentionOrgAndTeam := strings.Split(mention, "/")
 			if mentionOrgAndTeam[0][1:] == ctx.Metas["org"] && strings.Contains(teams, ","+strings.ToLower(mentionOrgAndTeam[1])+",") {
-				replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(setting.AppURL, "org", ctx.Metas["org"], "teams", mentionOrgAndTeam[1]), mention, "mention"))
+				replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(ctx.Links.Prefix(), "org", ctx.Metas["org"], "teams", mentionOrgAndTeam[1]), mention, "mention"))
 				node = node.NextSibling.NextSibling
 				start = 0
 				continue
@@ -620,7 +620,7 @@ func mentionProcessor(ctx *RenderContext, node *html.Node) {
 		mentionedUsername := mention[1:]
 
 		if DefaultProcessorHelper.IsUsernameMentionable != nil && DefaultProcessorHelper.IsUsernameMentionable(ctx.Ctx, mentionedUsername) {
-			replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(setting.AppURL, mentionedUsername), mention, "mention"))
+			replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(ctx.Links.Prefix(), mentionedUsername), mention, "mention"))
 			node = node.NextSibling.NextSibling
 		} else {
 			node = node.NextSibling
@@ -898,9 +898,9 @@ func issueIndexPatternProcessor(ctx *RenderContext, node *html.Node) {
 				path = "pulls"
 			}
 			if ref.Owner == "" {
-				link = createLink(util.URLJoin(setting.AppURL, ctx.Metas["user"], ctx.Metas["repo"], path, ref.Issue), reftext, "ref-issue")
+				link = createLink(util.URLJoin(ctx.Links.Prefix(), ctx.Metas["user"], ctx.Metas["repo"], path, ref.Issue), reftext, "ref-issue")
 			} else {
-				link = createLink(util.URLJoin(setting.AppURL, ref.Owner, ref.Name, path, ref.Issue), reftext, "ref-issue")
+				link = createLink(util.URLJoin(ctx.Links.Prefix(), ref.Owner, ref.Name, path, ref.Issue), reftext, "ref-issue")
 			}
 		}
 
@@ -939,7 +939,7 @@ func commitCrossReferencePatternProcessor(ctx *RenderContext, node *html.Node) {
 		}
 
 		reftext := ref.Owner + "/" + ref.Name + "@" + base.ShortSha(ref.CommitSha)
-		link := createLink(util.URLJoin(setting.AppSubURL, ref.Owner, ref.Name, "commit", ref.CommitSha), reftext, "commit")
+		link := createLink(util.URLJoin(ctx.Links.Prefix(), ref.Owner, ref.Name, "commit", ref.CommitSha), reftext, "commit")
 
 		replaceContent(node, ref.RefLocation.Start, ref.RefLocation.End, link)
 		node = node.NextSibling.NextSibling
@@ -1166,7 +1166,7 @@ func hashCurrentPatternProcessor(ctx *RenderContext, node *html.Node) {
 			continue
 		}
 
-		link := util.URLJoin(setting.AppURL, ctx.Metas["user"], ctx.Metas["repo"], "commit", hash)
+		link := util.URLJoin(ctx.Links.Prefix(), ctx.Metas["user"], ctx.Metas["repo"], "commit", hash)
 		replaceContent(node, m[2], m[3], createCodeLink(link, base.ShortSha(hash), "commit"))
 		start = 0
 		node = node.NextSibling.NextSibling

modules/markup/html_internal_test.go

@@ -287,6 +287,7 @@ func TestRender_IssueIndexPattern_Document(t *testing.T) {
 }
 
 func testRenderIssueIndexPattern(t *testing.T, input, expected string, ctx *RenderContext) {
+	ctx.Links.AbsolutePrefix = true
 	if ctx.Links.Base == "" {
 		ctx.Links.Base = TestRepoURL
 	}

modules/markup/html_test.go

@@ -43,7 +43,8 @@ func TestRender_Commits(t *testing.T) {
 			Ctx:          git.DefaultContext,
 			RelativePath: ".md",
 			Links: markup.Links{
-				Base: markup.TestRepoURL,
+				AbsolutePrefix: true,
+				Base:           markup.TestRepoURL,
 			},
 			Metas: localMetas,
 		}, input)
@@ -96,7 +97,8 @@ func TestRender_CrossReferences(t *testing.T) {
 			Ctx:          git.DefaultContext,
 			RelativePath: "a.md",
 			Links: markup.Links{
-				Base: setting.AppSubURL,
+				AbsolutePrefix: true,
+				Base:           setting.AppSubURL,
 			},
 			Metas: localMetas,
 		}, input)
@@ -588,7 +590,8 @@ func TestPostProcess_RenderDocument(t *testing.T) {
 		err := markup.PostProcess(&markup.RenderContext{
 			Ctx: git.DefaultContext,
 			Links: markup.Links{
-				Base: "https://example.com",
+				AbsolutePrefix: true,
+				Base:           "https://example.com",
 			},
 			Metas: localMetas,
 		}, strings.NewReader(input), &res)

modules/markup/markdown/markdown_test.go

@@ -130,11 +130,11 @@ func testAnswers(baseURLContent, baseURLImages string) []string {
 <li><a href="` + baseURLContent + `/Links" rel="nofollow">Links, Language bindings, Engine bindings</a></li>
 <li><a href="` + baseURLContent + `/Tips" rel="nofollow">Tips</a></li>
 </ul>
-<p>See commit <a href="http://localhost:3000/gogits/gogs/commit/65f1bf27bc" rel="nofollow"><code>65f1bf27bc</code></a></p>
+<p>See commit <a href="/gogits/gogs/commit/65f1bf27bc" rel="nofollow"><code>65f1bf27bc</code></a></p>
 <p>Ideas and codes</p>
 <ul>
-<li>Bezier widget (by <a href="` + AppURL + `r-lyeh" rel="nofollow">@r-lyeh</a>) <a href="http://localhost:3000/ocornut/imgui/issues/786" class="ref-issue" rel="nofollow">ocornut/imgui#786</a></li>
-<li>Bezier widget (by <a href="` + AppURL + `r-lyeh" rel="nofollow">@r-lyeh</a>) <a href="http://localhost:3000/gogits/gogs/issues/786" class="ref-issue" rel="nofollow">#786</a></li>
+<li>Bezier widget (by <a href="/r-lyeh" rel="nofollow">@r-lyeh</a>) <a href="http://localhost:3000/ocornut/imgui/issues/786" class="ref-issue" rel="nofollow">ocornut/imgui#786</a></li>
+<li>Bezier widget (by <a href="/r-lyeh" rel="nofollow">@r-lyeh</a>) <a href="http://localhost:3000/gogits/gogs/issues/786" class="ref-issue" rel="nofollow">#786</a></li>
 <li>Node graph editors <a href="https://github.com/ocornut/imgui/issues/306" rel="nofollow">https://github.com/ocornut/imgui/issues/306</a></li>
 <li><a href="` + baseURLContent + `/memory_editor_example" rel="nofollow">Memory Editor</a></li>
 <li><a href="` + baseURLContent + `/plot_var_example" rel="nofollow">Plot var helper</a></li>

modules/markup/renderer.go

@@ -82,9 +82,17 @@ type RenderContext struct {
 }
 
 type Links struct {
-	Base       string
-	BranchPath string
-	TreePath   string
+	AbsolutePrefix bool
+	Base           string
+	BranchPath     string
+	TreePath       string
+}
+
+func (l *Links) Prefix() string {
+	if l.AbsolutePrefix {
+		return setting.AppURL
+	}
+	return setting.AppSubURL
 }
 
 func (l *Links) HasBranchInfo() bool {