fix source download link when no code unit allowed (#3166)

templates/repo/release/list.tmpl

@@ -41,9 +41,11 @@
 								<a href="{{$.RepoLink}}/src/tag/{{.TagName}}" rel="nofollow"><i class="tag icon"></i> {{.TagName}}</a>
 							</h4>
 							<div class="download">
+							{{if $.Repository.UnitEnabled $.UnitTypeCode}}
 								<a href="{{$.RepoLink}}/src/commit/{{.Sha1}}" rel="nofollow"><i class="code icon"></i> {{ShortSha .Sha1}}</a>
 								<a href="{{$.RepoLink}}/archive/{{.TagName}}.zip" rel="nofollow"><i class="octicon octicon-file-zip"></i> ZIP</a>
 								<a href="{{$.RepoLink}}/archive/{{.TagName}}.tar.gz"><i class="octicon octicon-file-zip"></i> TAR.GZ</a>
+							{{end}}
 							</div>
 						{{else}}
 							<h3>
@@ -64,12 +66,14 @@
 							<div class="download">
 								<h2>{{$.i18n.Tr "repo.release.downloads"}}</h2>
 								<ul class="list">
+									{{if $.Repository.UnitEnabled $.UnitTypeCode}}
 									<li>
 										<a href="{{$.RepoLink}}/archive/{{.TagName}}.zip" rel="nofollow"><i class="octicon octicon-file-zip"></i> {{$.i18n.Tr "repo.release.source_code"}} (ZIP)</a>
 									</li>
 									<li>
 										<a href="{{$.RepoLink}}/archive/{{.TagName}}.tar.gz"><i class="octicon octicon-file-zip"></i> {{$.i18n.Tr "repo.release.source_code"}} (TAR.GZ)</a>
 									</li>
+									{{end}}
 									{{if .Attachments}}
 									{{range .Attachments}}
 									<li>