Add compare tag dropdown to releases page (#15695)

* Add compare tag dropdown to releases page

* Change defaults to be more intuitive and remove unneeded option

* Fix to select branch on releases page

Co-authored-by: Jonathan Tran <jon@allspice.io>
Co-authored-by: Kyle D <kdumontnu@gmail.com>

8 files changed, 78 insertions, 36 deletions

diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index 25b0a1b0bd..69923ebb83 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -855,6 +855,7 @@ branch = Branch
 tree = Tree
 clear_ref = `Clear current reference`
 filter_branch_and_tag = Filter branch or tag
+find_tag = Find tag
 branches = Branches
 tags = Tags
 issues = Issues
@@ -1913,6 +1914,7 @@ release.new_release = New Release
 release.draft = Draft
 release.prerelease = Pre-Release
 release.stable = Stable
+release.compare = Compare
 release.edit = edit
 release.ahead.commits = <strong>%d</strong> commits
 release.ahead.target = to %s since this release
diff --git a/routers/repo/release.go b/routers/repo/release.go
index abce3e9ac1..6b0b92743d 100644
--- a/routers/repo/release.go
+++ b/routers/repo/release.go
@@ -70,6 +70,11 @@ func TagsList(ctx *context.Context) {
 func releasesOrTags(ctx *context.Context, isTagList bool) {
 	ctx.Data["PageIsReleaseList"] = true
 	ctx.Data["DefaultBranch"] = ctx.Repo.Repository.DefaultBranch
+	ctx.Data["IsViewBranch"] = false
+	ctx.Data["IsViewTag"] = true
+	// Disable the showCreateNewBranch form in the dropdown on this page.
+	ctx.Data["CanCreateBranch"] = false
+	ctx.Data["HideBranchesInDropdown"] = true
 
 	if isTagList {
 		ctx.Data["Title"] = ctx.Tr("repo.release.tags")
@@ -79,6 +84,13 @@ func releasesOrTags(ctx *context.Context, isTagList bool) {
 		ctx.Data["PageIsTagList"] = false
 	}
 
+	tags, err := ctx.Repo.GitRepo.GetTags()
+	if err != nil {
+		ctx.ServerError("GetTags", err)
+		return
+	}
+	ctx.Data["Tags"] = tags
+
 	writeAccess := ctx.Repo.CanWrite(models.UnitTypeReleases)
 	ctx.Data["CanCreateRelease"] = writeAccess && !ctx.Repo.Repository.IsArchived
 
diff --git a/templates/repo/branch_dropdown.tmpl b/templates/repo/branch_dropdown.tmpl
index ca805fa587..3fd461c64f 100644
--- a/templates/repo/branch_dropdown.tmpl
+++ b/templates/repo/branch_dropdown.tmpl
@@ -1,64 +1,78 @@
-<div class="fitted item choose reference mr-1">
-	<div class="ui floating filter dropdown custom" data-can-create-branch="{{.CanCreateBranch}}" data-no-results="{{.i18n.Tr "repo.pulls.no_results"}}">
+{{$release := .release}}
+{{$showBranchesInDropdown := not .root.HideBranchesInDropdown}}
+<div class="fitted item choose reference{{if not $release}} mr-1{{end}}">
+	<div class="ui floating filter dropdown custom" data-can-create-branch="{{.root.CanCreateBranch}}" data-no-results="{{.root.i18n.Tr "repo.pulls.no_results"}}">
 		<div class="ui basic small compact button" @click="menuVisible = !menuVisible" @keyup.enter="menuVisible = !menuVisible">
 			<span class="text">
-				{{svg "octicon-git-branch"}}
-				{{if .IsViewBranch}}{{.i18n.Tr "repo.branch"}}{{else}}{{.i18n.Tr "repo.tree"}}{{end}}:
-				<strong>{{if .IsViewBranch}}{{.BranchName}}{{else}}{{ShortSha .BranchName}}{{end}}</strong>
+				{{if $release}}
+					{{.root.i18n.Tr "repo.release.compare"}}
+				{{else}}
+					{{svg "octicon-git-branch"}}
+					{{if .root.IsViewBranch}}{{.root.i18n.Tr "repo.branch"}}{{else}}{{.root.i18n.Tr "repo.tree"}}{{end}}:
+					<strong>{{if .root.IsViewBranch}}{{.root.BranchName}}{{else}}{{ShortSha .root.BranchName}}{{end}}</strong>
+				{{end}}
 			</span>
 			{{svg "octicon-triangle-down" 14 "dropdown icon"}}
 		</div>
-		<div class="data" style="display: none" data-mode="{{if .IsViewTag}}tags{{else}}branches{{end}}">
-			{{range .Branches}}
-				<div class="item branch {{if eq $.BranchName .}}selected{{end}}" data-url="{{$.RepoLink}}/{{if $.PageIsCommits}}commits{{else}}src{{end}}/branch/{{EscapePound .}}{{if $.TreePath}}/{{EscapePound $.TreePath}}{{end}}">{{.}}</div>
+		<div class="data" style="display: none" data-mode="{{if .root.IsViewTag}}tags{{else}}branches{{end}}">
+			{{if $showBranchesInDropdown}}
+				{{range .root.Branches}}
+					<div class="item branch {{if eq $.root.BranchName .}}selected{{end}}" data-url="{{$.root.RepoLink}}/{{if $.root.PageIsCommits}}commits{{else}}src{{end}}/branch/{{EscapePound .}}{{if $.root.TreePath}}/{{EscapePound $.root.TreePath}}{{end}}">{{.}}</div>
+				{{end}}
 			{{end}}
-			{{range .Tags}}
-				<div class="item tag {{if eq $.BranchName .}}selected{{end}}" data-url="{{$.RepoLink}}/{{if $.PageIsCommits}}commits{{else}}src{{end}}/tag/{{EscapePound .}}{{if $.TreePath}}/{{EscapePound $.TreePath}}{{end}}">{{.}}</div>
+			{{range .root.Tags}}
+				{{if $release}}
+					<div class="item tag {{if eq $release.TagName .}}selected{{end}}" data-url="{{$.root.RepoLink}}/compare/{{EscapePound .}}...{{if $release.TagName}}{{EscapePound $release.TagName}}{{else}}{{EscapePound $release.Sha1}}{{end}}">{{.}}</div>
+				{{else}}
+					<div class="item tag {{if eq $.root.BranchName .}}selected{{end}}" data-url="{{$.root.RepoLink}}/{{if $.root.PageIsCommits}}commits{{else}}src{{end}}/tag/{{EscapePound .}}{{if $.root.TreePath}}/{{EscapePound $.root.TreePath}}{{end}}">{{.}}</div>
+				{{end}}
 			{{end}}
 		</div>
 		<div class="menu transition" :class="{visible: menuVisible}" v-if="menuVisible" v-cloak>
 			<div class="ui icon search input">
 				<i class="icon df ac jc m-0">{{svg "octicon-filter" 16}}</i>
-				<input name="search" ref="searchField" v-model="searchTerm" @keydown="keydown($event)" placeholder="{{.i18n.Tr "repo.filter_branch_and_tag"}}...">
+				<input name="search" ref="searchField" v-model="searchTerm" @keydown="keydown($event)" placeholder="{{if $showBranchesInDropdown}}{{.root.i18n.Tr "repo.filter_branch_and_tag"}}{{else}}{{.root.i18n.Tr "repo.find_tag"}}{{end}}...">
 			</div>
-			<div class="header branch-tag-choice">
-				<div class="ui grid">
-					<div class="two column row">
-						<a class="reference column" href="#" @click="createTag = false; mode = 'branches'; focusSearchField()">
-							<span class="text" :class="{black: mode == 'branches'}">
-								{{svg "octicon-git-branch" 16 "mr-2"}}{{.i18n.Tr "repo.branches"}}
-							</span>
-						</a>
-						<a class="reference column" href="#" @click="createTag = true; mode = 'tags'; focusSearchField()">
-							<span class="text" :class="{black: mode == 'tags'}">
-								{{svg "octicon-tag" 16 "mr-2"}}{{.i18n.Tr "repo.tags"}}
-							</span>
-						</a>
+			{{if $showBranchesInDropdown}}
+				<div class="header branch-tag-choice">
+					<div class="ui grid">
+						<div class="two column row">
+							<a class="reference column" href="#" @click="createTag = false; mode = 'branches'; focusSearchField()">
+								<span class="text" :class="{black: mode == 'branches'}">
+									{{svg "octicon-git-branch" 16 "mr-2"}}{{.root.i18n.Tr "repo.branches"}}
+								</span>
+							</a>
+							<a class="reference column" href="#" @click="createTag = true; mode = 'tags'; focusSearchField()">
+								<span class="text" :class="{black: mode == 'tags'}">
+									{{svg "octicon-tag" 16 "mr-2"}}{{.root.i18n.Tr "repo.tags"}}
+								</span>
+							</a>
+						</div>
 					</div>
 				</div>
-			</div>
+			{{end}}
 			<div class="scrolling menu" ref="scrollContainer">
 				<div v-for="(item, index) in filteredItems" :key="item.name" class="item" :class="{selected: item.selected, active: active == index}" @click="selectItem(item)" :ref="'listItem' + index">${ item.name }</div>
 				<div class="item" v-if="showCreateNewBranch" :class="{active: active == filteredItems.length}" :ref="'listItem' + filteredItems.length">
 					<a href="#" @click="createNewBranch()">
 						<div v-show="createTag">
 							<i class="reference tags icon"></i>
-							{{.i18n.Tr "repo.tag.create_tag" `${ searchTerm }` | Safe}}
+							{{.root.i18n.Tr "repo.tag.create_tag" `${ searchTerm }` | Safe}}
 						</div>
 						<div v-show="!createTag">
 							{{svg "octicon-git-branch"}}
-							{{.i18n.Tr "repo.branch.create_branch" `${ searchTerm }` | Safe}}
+							{{.root.i18n.Tr "repo.branch.create_branch" `${ searchTerm }` | Safe}}
 						</div>
 						<div class="text small">
-							{{if .IsViewBranch}}
-								{{.i18n.Tr "repo.branch.create_from" .BranchName}}
+							{{if or .root.IsViewBranch $release}}
+								{{.root.i18n.Tr "repo.branch.create_from" .root.BranchName}}
 							{{else}}
-								{{.i18n.Tr "repo.branch.create_from" (ShortSha .BranchName)}}
+								{{.root.i18n.Tr "repo.branch.create_from" (ShortSha .root.BranchName)}}
 							{{end}}
 						</div>
 					</a>
-					<form ref="newBranchForm" action="{{.RepoLink}}/branches/_new/{{EscapePound .BranchNameSubURL}}" method="post">
-						{{.CsrfTokenHtml}}
+					<form ref="newBranchForm" action="{{.root.RepoLink}}/branches/_new/{{EscapePound .root.BranchNameSubURL}}" method="post">
+						{{.root.CsrfTokenHtml}}
 						<input type="hidden" name="new_branch_name" v-model="searchTerm">
 						<input type="hidden" name="create_tag" v-model="createTag">
 					</form>
diff --git a/templates/repo/commits.tmpl b/templates/repo/commits.tmpl
index 5a8a89fe14..1e2b0f7d90 100644
--- a/templates/repo/commits.tmpl
+++ b/templates/repo/commits.tmpl
@@ -4,7 +4,7 @@
 	<div class="ui container">
 		{{template "repo/sub_menu" .}}
 		<div class="ui secondary stackable menu mobile--margin-between-items">
-		{{template "repo/branch_dropdown" .}}
+		{{template "repo/branch_dropdown" dict "root" .}}
 			<div class="fitted item">
 				<a href="{{.RepoLink}}/graph" class="ui basic small compact button">
 					<span class="text">
diff --git a/templates/repo/home.tmpl b/templates/repo/home.tmpl
index ed31398355..254bbb7380 100644
--- a/templates/repo/home.tmpl
+++ b/templates/repo/home.tmpl
@@ -57,7 +57,7 @@
 		{{end}}
 		{{template "repo/sub_menu" .}}
 		<div class="ui stackable secondary menu mobile--margin-between-items mobile--no-negative-margins">
-			{{template "repo/branch_dropdown" .}}
+			{{template "repo/branch_dropdown" dict "root" .}}
 			{{ $n := len .TreeNames}}
 			{{ $l := Subtract $n 1}}
 			<!-- If home page, show new PR. If not, show breadcrumb -->
diff --git a/templates/repo/release/list.tmpl b/templates/repo/release/list.tmpl
index ce4de3ddfa..6829e3e8e2 100644
--- a/templates/repo/release/list.tmpl
+++ b/templates/repo/release/list.tmpl
@@ -80,6 +80,7 @@
 							<span class="commit">
 								<a class="mono" href="{{$.RepoLink}}/src/commit/{{.Sha1}}" rel="nofollow">{{svg "octicon-git-commit" 16 "mr-2"}}{{ShortSha .Sha1}}</a>
 							</span>
+							{{template "repo/branch_dropdown" dict "root" $ "release" .}}
 						{{end}}
 					</div>
 					<div class="ui twelve wide column detail">
diff --git a/web_src/js/index.js b/web_src/js/index.js
index 1716df9e7f..89cc0aa11c 100644
--- a/web_src/js/index.js
+++ b/web_src/js/index.js
@@ -781,7 +781,8 @@ async function initRepository() {
   });
 
   // File list and commits
-  if ($('.repository.file.list').length > 0 || ('.repository.commits').length > 0) {
+  if ($('.repository.file.list').length > 0 ||
+    $('.repository.commits').length > 0 || $('.repository.release').length > 0) {
     initFilterBranchTagDropdown('.choose.reference .dropdown');
   }
 
diff --git a/web_src/less/_repository.less b/web_src/less/_repository.less
index 70ad8dd730..5ff51b1d6d 100644
--- a/web_src/less/_repository.less
+++ b/web_src/less/_repository.less
@@ -1803,6 +1803,10 @@
           text-align: right;
           position: relative;
 
+          .label {
+            margin-right: 0;
+          }
+
           .tag:not(.icon) {
             display: block;
             margin-top: 15px;
@@ -1812,6 +1816,14 @@
             display: block;
             margin-top: 10px;
           }
+
+          .choose {
+            margin-top: 15px;
+
+            .button {
+              margin-right: 0;
+            }
+          }
         }
 
         .detail {
@@ -1855,7 +1867,7 @@
             width: 9px;
             height: 9px;
             background-color: #ddd;
-            z-index: 999;
+            z-index: 9;
             position: absolute;
             display: block;
             left: -5px;