Improve tree not found page

modules/context/context_response.go

@@ -16,6 +16,7 @@ import (
 
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/httplib"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -136,6 +137,11 @@ func (ctx *Context) notFoundInternal(logMsg string, logErr error) {
 
 	ctx.Data["IsRepo"] = ctx.Repo.Repository != nil
 	ctx.Data["Title"] = "Page Not Found"
+
+	if git.IsErrNotExist(logErr) {
+		ctx.Data["NotFoundPrompt"] = ctx.Locale.Tr("repo.tree_not_found", ctx.Repo.BranchName, ctx.Repo.Repository.Name, ctx.Repo.TreePath)
+		ctx.Data["NotFoundGoBackURL"] = ctx.Repo.RepoLink + "/src/branch/" + url.PathEscape(ctx.Repo.BranchName)
+	}
 	ctx.HTML(http.StatusNotFound, base.TplName("status/404"))
 }
 

options/locale/locale_en-US.ini

@@ -112,6 +112,7 @@ step2 = Step 2:
 
 error = Error
 error404 = The page you are trying to reach either <strong>does not exist</strong> or <strong>you are not authorized</strong> to view it.
+back = Back
 
 never = Never
 unknown = Unknown
@@ -1007,6 +1008,8 @@ delete_preexisting_success = Deleted unadopted files in %s
 blame_prior = View blame prior to this change
 author_search_tooltip = Shows a maximum of 30 users
 
+tree_not_found = The %s branch of %s does not contain the path %s
+
 transfer.accept = Accept Transfer
 transfer.accept_desc =  Transfer to "%s"
 transfer.reject = Reject Transfer

templates/status/404.tmpl

@@ -3,9 +3,12 @@
 	{{if .IsRepo}}{{template "repo/header" .}}{{end}}
 	<div class="ui container center">
 		<p style="margin-top: 100px"><img src="{{AssetUrlPrefix}}/img/404.png" alt="404"></p>
+		<p>{{if .NotFoundPrompt}}{{.NotFoundPrompt}}{{else}}{{.locale.Tr "error404" | Safe}}{{end}}</p>
+		{{if .NotFoundGoBackURL}}<a class="ui button green" href="{{.NotFoundGoBackURL}}">{{.locale.Tr "back"}}</a>{{end}}
+
 		<div class="divider"></div>
 		<br>
-		<p>{{.locale.Tr "error404" | Safe}}</p>
+
 		{{if .ShowFooterVersion}}<p>{{.locale.Tr "admin.config.app_ver"}}: {{AppVer}}</p>{{end}}
 	</div>
 </div>