Fix "redirect link" handling (#33440)

`a%2fb` should not redirect to `a/b`

---------

Co-authored-by: delvh <dev.lh@web.de>

routers/web/repo/view_home.go

@@ -413,8 +413,19 @@ 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 us 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.
+	redirect := ctx.Repo.RepoLink + "/src/" + ctx.PathParamRaw("*")
+	if ctx.Req.URL.RawQuery != "" {
+		redirect += "?" + ctx.Req.URL.RawQuery
+	}
+	ctx.Redirect(redirect)
 }