Fix a bug returning 404 when display a single tag with no release (#29466)

Partially caused by #29149 

When use

```go
releases, err := getReleaseInfos(ctx, &repo_model.FindReleasesOptions{
		ListOptions: db.ListOptions{Page: 1, PageSize: 1},
		RepoID:      ctx.Repo.Repository.ID,
		TagNames:    []string{ctx.Params("*")},
		// only show draft releases for users who can write, read-only users shouldn't see draft releases.
		IncludeDrafts: writeAccess,
	})
```
replace
```go
release, err := repo_model.GetRelease(ctx, ctx.Repo.Repository.ID, ctx.Params("*"))
```
It missed `IncludeTags: true,`. That means this bug will be occupied only when the release is a tag.
This PR will fix

 - Get the right tag record when it's not a release
 - Display correct tag tab but not release tag when it's a tag.
- The button will bring the tag name to the new page when it's a single tag page
- the new page will automatically hide the release target inputbox when the tag name is pre filled. This should be backport to v1.21.

5 files changed, 23 insertions, 8 deletions

diff --git a/routers/web/repo/release.go b/routers/web/repo/release.go
index c6d8c45af1..dbc190928f 100644
--- a/routers/web/repo/release.go
+++ b/routers/web/repo/release.go
@@ -185,6 +185,11 @@ func Releases(ctx *context.Context) {
 		ctx.ServerError("getReleaseInfos", err)
 		return
 	}
+	for _, rel := range releases {
+		if rel.Release.IsTag && rel.Release.Title == "" {
+			rel.Release.Title = rel.Release.TagName
+		}
+	}
 
 	ctx.Data["Releases"] = releases
 
@@ -283,6 +288,7 @@ func SingleRelease(ctx *context.Context) {
 		TagNames:    []string{ctx.Params("*")},
 		// only show draft releases for users who can write, read-only users shouldn't see draft releases.
 		IncludeDrafts: writeAccess,
+		IncludeTags:   true,
 	})
 	if err != nil {
 		ctx.ServerError("getReleaseInfos", err)
@@ -294,6 +300,9 @@ func SingleRelease(ctx *context.Context) {
 	}
 
 	release := releases[0].Release
+	if release.IsTag && release.Title == "" {
+		release.Title = release.TagName
+	}
 
 	ctx.Data["PageIsSingleTag"] = release.IsTag
 	if release.IsTag {
diff --git a/templates/repo/release/list.tmpl b/templates/repo/release/list.tmpl
index 7f38fa3ff0..873cccab79 100644
--- a/templates/repo/release/list.tmpl
+++ b/templates/repo/release/list.tmpl
@@ -18,18 +18,18 @@
 					<div class="ui twelve wide column detail">
 						<div class="gt-df gt-ac gt-sb gt-fw gt-mb-3">
 							<h4 class="release-list-title gt-word-break">
-								<a href="{{$.RepoLink}}/releases/tag/{{$release.TagName | PathEscapeSegments}}">{{$release.Title}}</a>
+								{{if $.PageIsSingleTag}}{{$release.Title}}{{else}}<a href="{{$.RepoLink}}/releases/tag/{{$release.TagName | PathEscapeSegments}}">{{$release.Title}}</a>{{end}}
 								{{template "repo/commit_statuses" dict "Status" $info.CommitStatus "Statuses" $info.CommitStatuses "AdditionalClasses" "gt-df"}}
 								{{if $release.IsDraft}}
 									<span class="ui yellow label">{{ctx.Locale.Tr "repo.release.draft"}}</span>
 								{{else if $release.IsPrerelease}}
 									<span class="ui orange label">{{ctx.Locale.Tr "repo.release.prerelease"}}</span>
-								{{else}}
+								{{else if (not $release.IsTag)}}
 									<span class="ui green label">{{ctx.Locale.Tr "repo.release.stable"}}</span>
 								{{end}}
 							</h4>
 							<div>
-								{{if $.CanCreateRelease}}
+								{{if and $.CanCreateRelease (not $.PageIsSingleTag)}}
 									<a class="muted" data-tooltip-content="{{ctx.Locale.Tr "repo.release.edit"}}" href="{{$.RepoLink}}/releases/edit/{{$release.TagName | PathEscapeSegments}}" rel="nofollow">
 										{{svg "octicon-pencil"}}
 									</a>
diff --git a/templates/repo/release_tag_header.tmpl b/templates/repo/release_tag_header.tmpl
index 31c151da08..8e6088790d 100644
--- a/templates/repo/release_tag_header.tmpl
+++ b/templates/repo/release_tag_header.tmpl
@@ -5,9 +5,9 @@
 	<div class="gt-df">
 		<div class="gt-f1 gt-df gt-ac">
 			<h2 class="ui compact small menu header small-menu-items">
-				<a class="{{if .PageIsReleaseList}}active {{end}}item" href="{{.RepoLink}}/releases">{{ctx.Locale.PrettyNumber .NumReleases}} {{ctx.Locale.TrN .NumReleases "repo.release" "repo.releases"}}</a>
+				<a class="{{if and .PageIsReleaseList (not .PageIsSingleTag)}}active {{end}}item" href="{{.RepoLink}}/releases">{{ctx.Locale.PrettyNumber .NumReleases}} {{ctx.Locale.TrN .NumReleases "repo.release" "repo.releases"}}</a>
 				{{if $canReadCode}}
-					<a class="{{if .PageIsTagList}}active {{end}}item" href="{{.RepoLink}}/tags">{{ctx.Locale.PrettyNumber .NumTags}} {{ctx.Locale.TrN .NumTags "repo.tag" "repo.tags"}}</a>
+					<a class="{{if or .PageIsTagList .PageIsSingleTag}}active {{end}}item" href="{{.RepoLink}}/tags">{{ctx.Locale.PrettyNumber .NumTags}} {{ctx.Locale.TrN .NumTags "repo.tag" "repo.tags"}}</a>
 				{{end}}
 			</h2>
 		</div>
@@ -17,7 +17,7 @@
 			</a>
 		{{end}}
 		{{if and (not .PageIsTagList) .CanCreateRelease}}
-			<a class="ui small primary button" href="{{$.RepoLink}}/releases/new">
+			<a class="ui small primary button" href="{{$.RepoLink}}/releases/new{{if .PageIsSingleTag}}?tag={{.TagName}}{{end}}">
 				{{ctx.Locale.Tr "repo.release.new_release"}}
 			</a>
 		{{end}}
diff --git a/tests/integration/links_test.go b/tests/integration/links_test.go
index a3937dd697..d103e2b0a9 100644
--- a/tests/integration/links_test.go
+++ b/tests/integration/links_test.go
@@ -36,6 +36,7 @@ func TestLinksNoLogin(t *testing.T) {
 		"/user2/repo1/",
 		"/user2/repo1/projects",
 		"/user2/repo1/projects/1",
+		"/user2/repo1/releases/tag/delete-tag", // It's the only one existing record on release.yml which has is_tag: true
 		"/assets/img/404.png",
 		"/assets/img/500.png",
 		"/.well-known/security.txt",
diff --git a/web_src/js/features/repo-release.js b/web_src/js/features/repo-release.js
index 2db8079009..f3cfa74418 100644
--- a/web_src/js/features/repo-release.js
+++ b/web_src/js/features/repo-release.js
@@ -30,8 +30,9 @@ function initTagNameEditor() {
   const newTagHelperText = el.getAttribute('data-tag-helper-new');
   const existingTagHelperText = el.getAttribute('data-tag-helper-existing');
 
-  document.getElementById('tag-name').addEventListener('keyup', (e) => {
-    const value = e.target.value;
+  const tagNameInput = document.getElementById('tag-name');
+  const hideTargetInput = function(tagNameInput) {
+    const value = tagNameInput.value;
     const tagHelper = document.getElementById('tag-helper');
     if (existingTags.includes(value)) {
       // If the tag already exists, hide the target branch selector.
@@ -41,6 +42,10 @@ function initTagNameEditor() {
       showElem('#tag-target-selector');
       tagHelper.textContent = value ? newTagHelperText : defaultTagHelperText;
     }
+  };
+  hideTargetInput(tagNameInput); // update on page load because the input may have a value
+  tagNameInput.addEventListener('input', (e) => {
+    hideTargetInput(e.target);
   });
 }