Pass correct tag target to post-receive hook when creating tag via UIpass-correct-tag-target-to-post-receive

We need to handle annotated tags that are created via GitLab UI.
Annotated tags have their own SHA. We have to pass this SHA to
post-receive hook to mirror what happens when someone creates
an annotated tag in their local repository and pushes it via
command line.
In order to obtain tag SHA we first have to create it. This is
a bit confusing because we create the tag before executing
pre-hooks, but there is no way to create a tag outside the
repository. If pre-hooks fail we have to clean up after ourselves.

3 files changed, 36 insertions, 3 deletions

diff --git a/app/models/repository.rb b/app/models/repository.rb
index 146424d2b1c..31be06be50c 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -176,11 +176,18 @@ class Repository
 
     options = { message: message, tagger: user_to_committer(user) } if message
 
-    GitHooksService.new.execute(user, path_to_repo, oldrev, target, ref) do
-      rugged.tags.create(tag_name, target, options)
+    rugged.tags.create(tag_name, target, options)
+    tag = find_tag(tag_name)
+
+    GitHooksService.new.execute(user, path_to_repo, oldrev, tag.target, ref) do
+      # we already created a tag, because we need tag SHA to pass correct
+      # values to hooks
     end
 
-    find_tag(tag_name)
+    tag
+  rescue GitHooksService::PreReceiveError
+    rugged.tags.delete(tag_name)
+    raise
   end
 
   def rm_branch(user, branch_name)
diff --git a/changelogs/unreleased/pass-correct-tag-target-to-post-receive.yml b/changelogs/unreleased/pass-correct-tag-target-to-post-receive.yml
new file mode 100644
index 00000000000..5e868027ed6
--- /dev/null
+++ b/changelogs/unreleased/pass-correct-tag-target-to-post-receive.yml
@@ -0,0 +1,4 @@
+---
+title: Pass correct tag target to post-receive hook when creating tag via UI
+merge_request: 7556
+author:
diff --git a/spec/models/repository_spec.rb b/spec/models/repository_spec.rb
index 2470d504c68..72ac41f3472 100644
--- a/spec/models/repository_spec.rb
+++ b/spec/models/repository_spec.rb
@@ -1354,6 +1354,28 @@ describe Repository, models: true do
         repository.add_tag(user, '8.5', 'master', 'foo')
       end
 
+      it 'does not create a tag when a pre-hook fails' do
+        allow_any_instance_of(Gitlab::Git::Hook).to receive(:trigger).and_return([false, ''])
+
+        expect do
+          repository.add_tag(user, '8.5', 'master', 'foo')
+        end.to raise_error(GitHooksService::PreReceiveError)
+
+        repository.expire_tags_cache
+        expect(repository.find_tag('8.5')).to be_nil
+      end
+
+      it 'passes tag SHA to hooks' do
+        spy = GitHooksService.new
+        allow(GitHooksService).to receive(:new).and_return(spy)
+        allow(spy).to receive(:execute).and_call_original
+
+        tag = repository.add_tag(user, '8.5', 'master', 'foo')
+
+        expect(spy).to have_received(:execute).
+          with(anything, anything, anything, tag.target, anything)
+      end
+
       it 'returns a Gitlab::Git::Tag object' do
         tag = repository.add_tag(user, '8.5', 'master', 'foo')