Fix "redirect link" handling

routers/web/repo/view_home.go

@@ -413,8 +413,15 @@ func Home(ctx *context.Context) {
 	ctx.HTML(http.StatusOK, tplRepoHome)
 }
 
-// HomeRedirect redirects from /tree/* to /src/* in order to maintain a similar URL structure.
-func HomeRedirect(ctx *context.Context) {
-	remainder := ctx.PathParam("*")
-	ctx.Redirect(ctx.Repo.RepoLink + "/src/" + util.PathEscapeSegments(remainder))
+func RedirectRepoTreeToSrc(ctx *context.Context) {
+	// Redirect "/owner/repo/tree/*" requests to "/owner/repo/src/*",
+	// then use the deprecated "/src/*" handler to guess the ref type and render a file list page.
+	// This is done intentionally so that Gitea's repo URL structure matches other forges (GitHub/GitLab) provide,
+	// allowing we to construct submodule URLs across forges easily.
+	// For example, when viewing a submodule, we can simply construct the link as:
+	// * "https://gitea/owner/repo/tree/{CommitID}"
+	// * "https://github/owner/repo/tree/{CommitID}"
+	// * "https://gitlab/owner/repo/tree/{CommitID}"
+	// Then no matter which forge the submodule is using, the link works.
+	ctx.Redirect(ctx.Repo.RepoLink + "/src/" + ctx.PathParamRaw("*"))
 }

routers/web/web.go

@@ -1583,13 +1583,7 @@ func registerRoutes(m *web.Router) {
 			m.Get("/commit/*", context.RepoRefByType(git.RefTypeCommit), repo.Home)
 			m.Get("/*", context.RepoRefByType(""), repo.Home) // "/*" route is deprecated, and kept for backward compatibility
 		}, repo.SetEditorconfigIfExists)
-
-		// Add a /tree/* path to redirect to the /src/* path, which
-		// will redirect to the canonical URL for that ref. This is
-		// included so that Gitea's repo URL structure matches what
-		// other forges provide, allowing clients to construct URLs
-		// that work across forges.
-		m.Get("/tree/*", repo.HomeRedirect)
+		m.Get("/tree/*", repo.RedirectRepoTreeToSrc) // redirect "/owner/repo/tree/*" requests to "/owner/repo/src/*"
 
 		m.Get("/forks", context.RepoRef(), repo.Forks)
 		m.Get("/commit/{sha:([a-f0-9]{7,64})}.{ext:patch|diff}", repo.MustBeNotEmpty, repo.RawDiff)

services/context/repo.go

@@ -897,6 +897,7 @@ func RepoRefByType(detectRefType git.RefType) func(*Context) {
 
 			if guessLegacyPath {
 				// redirect from old URL scheme to new URL scheme
+				// FIXME: the path handling is not right here
 				prefix := strings.TrimPrefix(setting.AppSubURL+strings.ToLower(strings.TrimSuffix(ctx.Req.URL.Path, ctx.PathParam("*"))), strings.ToLower(ctx.Repo.RepoLink))
 				redirect := path.Join(
 					ctx.Repo.RepoLink,

tests/integration/links_test.go

@@ -52,9 +52,11 @@ func TestRedirectsNoLogin(t *testing.T) {
 	redirects := []struct{ from, to string }{
 		{"/user2/repo1/commits/master", "/user2/repo1/commits/branch/master"},
 		{"/user2/repo1/src/master", "/user2/repo1/src/branch/master"},
-		{"/user2/repo1/src/master/file.txt", "/user2/repo1/src/branch/master/file.txt"},
+		{"/user2/repo1/src/master/a%2fb.txt", "/user2/repo1/src/branch/master/a%2fb.txt"},
 		{"/user2/repo1/src/master/directory/file.txt", "/user2/repo1/src/branch/master/directory/file.txt"},
-		{"/user/avatar/Ghost/-1", "/assets/img/avatar_default.png"},
+		{"/user2/repo1/tree/a%2fb", "/user2/repo1/src/a%2fb"},
+		{"/user/avatar/GhosT/-1", "/assets/img/avatar_default.png"},
+		{"/user/avatar/Gitea-ActionS/0", "/assets/img/avatar_default.png"},
 		{"/api/v1/swagger", "/api/swagger"},
 	}
 	for _, c := range redirects {