Improve tree not found page

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.
+go_back = Go 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_path_not_found = Path %[1]s doesn't exist in branch %[2]s
+
 transfer.accept = Accept Transfer
 transfer.accept_desc =  Transfer to "%s"
 transfer.reject = Reject Transfer

routers/web/repo/blame.go

@@ -74,7 +74,7 @@ func RefBlame(ctx *context.Context) {
 	// Get current entry user currently looking at.
 	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
 	if err != nil {
-		ctx.NotFoundOrServerError("Repo.Commit.GetTreeEntryByPath", git.IsErrNotExist, err)
+		HandleGitError(ctx, "Repo.Commit.GetTreeEntryByPath", err)
 		return
 	}
 

routers/web/repo/editor.go

@@ -123,7 +123,7 @@ func editFile(ctx *context.Context, isNewFile bool) {
 	if !isNewFile {
 		entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
 		if err != nil {
-			ctx.NotFoundOrServerError("GetTreeEntryByPath", git.IsErrNotExist, err)
+			HandleGitError(ctx, "Repo.Commit.GetTreeEntryByPath", err)
 			return
 		}
 

routers/web/repo/helper.go

@@ -4,10 +4,12 @@
 package repo
 
 import (
+	"net/url"
 	"sort"
 
 	"code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
 )
 
 func MakeSelfOnTop(ctx *context.Context, users []*user.User) []*user.User {
@@ -21,3 +23,11 @@ func MakeSelfOnTop(ctx *context.Context, users []*user.User) []*user.User {
 	}
 	return users
 }
+
+func HandleGitError(ctx *context.Context, msg string, err error) {
+	if git.IsErrNotExist(err) {
+		ctx.Data["NotFoundPrompt"] = ctx.Locale.Tr("repo.tree_path_not_found", ctx.Repo.TreePath, ctx.Repo.BranchName)
+		ctx.Data["NotFoundGoBackURL"] = ctx.Repo.RepoLink + "/src/branch/" + url.PathEscape(ctx.Repo.BranchName)
+	}
+	ctx.NotFoundOrServerError(msg, git.IsErrNotExist, err)
+}

routers/web/repo/view.go

@@ -700,7 +700,7 @@ func checkCitationFile(ctx *context.Context, entry *git.TreeEntry) {
 	}
 	tree, err := ctx.Repo.Commit.SubTree(ctx.Repo.TreePath)
 	if err != nil {
-		ctx.NotFoundOrServerError("Repo.Commit.SubTree", git.IsErrNotExist, err)
+		HandleGitError(ctx, "Repo.Commit.SubTree", err)
 		return
 	}
 	allEntries, err := tree.ListEntries()
@@ -791,7 +791,7 @@ func LastCommit(ctx *context.Context) {
 func renderDirectoryFiles(ctx *context.Context, timeout time.Duration) git.Entries {
 	tree, err := ctx.Repo.Commit.SubTree(ctx.Repo.TreePath)
 	if err != nil {
-		ctx.NotFoundOrServerError("Repo.Commit.SubTree", git.IsErrNotExist, err)
+		HandleGitError(ctx, "Repo.Commit.SubTree", err)
 		return nil
 	}
 
@@ -800,12 +800,12 @@ func renderDirectoryFiles(ctx *context.Context, timeout time.Duration) git.Entri
 	// Get current entry user currently looking at.
 	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
 	if err != nil {
-		ctx.NotFoundOrServerError("Repo.Commit.GetTreeEntryByPath", git.IsErrNotExist, err)
+		HandleGitError(ctx, "Repo.Commit.GetTreeEntryByPath", err)
 		return nil
 	}
 
 	if !entry.IsDir() {
-		ctx.NotFoundOrServerError("Repo.Commit.GetTreeEntryByPath", git.IsErrNotExist, err)
+		HandleGitError(ctx, "Repo.Commit.GetTreeEntryByPath", err)
 		return nil
 	}
 
@@ -971,7 +971,7 @@ func renderCode(ctx *context.Context) {
 	// Get current entry user currently looking at.
 	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
 	if err != nil {
-		ctx.NotFoundOrServerError("Repo.Commit.GetTreeEntryByPath", git.IsErrNotExist, err)
+		HandleGitError(ctx, "Repo.Commit.GetTreeEntryByPath", err)
 		return
 	}
 

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 "go_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>