Creates /create_merge_request quickaction40085-add-a-create_merge_request-quick-action

With this quick action the user can create a new MR starting from
the current issue using as `source_branch` the given `branch name` and
as `target_branch` the project default branch. If the `branch name` is
omitted a name is automatically created starting from the issue title.

11 files changed, 182 insertions, 6 deletions

diff --git a/app/services/issues/update_service.rb b/app/services/issues/update_service.rb
index fba252b0bae..a1d0cc0e568 100644
--- a/app/services/issues/update_service.rb
+++ b/app/services/issues/update_service.rb
@@ -11,6 +11,12 @@ module Issues
       move_issue_to_new_project(issue) || update(issue)
     end
 
+    def update(issue)
+      create_merge_request_from_quick_action
+
+      super
+    end
+
     def before_update(issue)
       spam_check(issue, current_user)
     end
@@ -93,6 +99,13 @@ module Issues
 
     private
 
+    def create_merge_request_from_quick_action
+      create_merge_request_params = params.delete(:create_merge_request)
+      return unless create_merge_request_params
+
+      MergeRequests::CreateFromIssueService.new(project, current_user, create_merge_request_params).execute
+    end
+
     def handle_milestone_change(issue)
       return if skip_milestone_email
 
diff --git a/app/services/merge_requests/create_from_issue_service.rb b/app/services/merge_requests/create_from_issue_service.rb
index 020af0bb950..e69791872cc 100644
--- a/app/services/merge_requests/create_from_issue_service.rb
+++ b/app/services/merge_requests/create_from_issue_service.rb
@@ -19,13 +19,15 @@ module MergeRequests
       result = CreateBranchService.new(project, current_user).execute(branch_name, ref)
       return result if result[:status] == :error
 
-      SystemNoteService.new_issue_branch(issue, project, current_user, branch_name)
-
       new_merge_request = create(merge_request)
 
       if new_merge_request.valid?
+        SystemNoteService.new_merge_request(issue, project, current_user, new_merge_request)
+
         success(new_merge_request)
       else
+        SystemNoteService.new_issue_branch(issue, project, current_user, branch_name)
+
         error(new_merge_request.errors)
       end
     end
diff --git a/app/services/quick_actions/interpret_service.rb b/app/services/quick_actions/interpret_service.rb
index 9c81de7e90e..d248b10f41e 100644
--- a/app/services/quick_actions/interpret_service.rb
+++ b/app/services/quick_actions/interpret_service.rb
@@ -635,6 +635,22 @@ module QuickActions
       @updates[:tag_message] = message
     end
 
+    desc 'Create a merge request.'
+    explanation do |branch_name = nil|
+      branch_text = branch_name ? "branch '#{branch_name}'" : 'a branch'
+      "Creates #{branch_text} and a merge request to resolve this issue"
+    end
+    params "<branch name>"
+    condition do
+      issuable.is_a?(Issue) && current_user.can?(:create_merge_request_in, project) && current_user.can?(:push_code, project)
+    end
+    command :create_merge_request do |branch_name = nil|
+      @updates[:create_merge_request] = {
+        branch_name: branch_name,
+        issue_iid: issuable.iid
+      }
+    end
+
     # rubocop: disable CodeReuse/ActiveRecord
     def extract_users(params)
       return [] if params.nil?
diff --git a/app/services/system_note_service.rb b/app/services/system_note_service.rb
index 729bc991294..ec6c306227b 100644
--- a/app/services/system_note_service.rb
+++ b/app/services/system_note_service.rb
@@ -407,11 +407,17 @@ module SystemNoteService
   def new_issue_branch(issue, project, author, branch)
     link = url_helpers.project_compare_url(project, from: project.default_branch, to: branch)
 
-    body = "created branch [`#{branch}`](#{link})"
+    body = "created branch [`#{branch}`](#{link}) to address this issue"
 
     create_note(NoteSummary.new(issue, project, author, body, action: 'branch'))
   end
 
+  def new_merge_request(issue, project, author, merge_request)
+    body = "created merge request #{merge_request.to_reference} to address this issue"
+
+    create_note(NoteSummary.new(issue, project, author, body, action: 'merge'))
+  end
+
   # Called when a Mentionable references a Noteable
   #
   # noteable  - Noteable object being referenced
diff --git a/changelogs/unreleased/40085-add-a-create_merge_request-quick-action.yml b/changelogs/unreleased/40085-add-a-create_merge_request-quick-action.yml
new file mode 100644
index 00000000000..e1614ac7669
--- /dev/null
+++ b/changelogs/unreleased/40085-add-a-create_merge_request-quick-action.yml
@@ -0,0 +1,5 @@
+---
+title: Creates /create_merge_request quickaction
+merge_request: 22485
+author: Jacopo Beschi @jacopo-beschi
+type: added
diff --git a/doc/user/project/quick_actions.md b/doc/user/project/quick_actions.md
index 0a4542b71ed..85a03d125dd 100644
--- a/doc/user/project/quick_actions.md
+++ b/doc/user/project/quick_actions.md
@@ -53,6 +53,7 @@ discussions, and descriptions:
 | `/target_branch <Local branch Name>` | Set target branch    |       | ✓             |
 | `/wip`                     | Toggle the Work In Progress status |   | ✓             |
 | `/merge`                   | Merge (when pipeline succeeds) |       | ✓             |
+| `/create_merge_request <branch name>` | Create a new merge request starting from the current issue | ✓ | |
 
 
 ## Quick actions for commit messages
diff --git a/spec/features/issues/user_creates_branch_and_merge_request_spec.rb b/spec/features/issues/user_creates_branch_and_merge_request_spec.rb
index 3dfcbc2fcb8..a912c327728 100644
--- a/spec/features/issues/user_creates_branch_and_merge_request_spec.rb
+++ b/spec/features/issues/user_creates_branch_and_merge_request_spec.rb
@@ -76,7 +76,7 @@ describe 'User creates branch and merge request on issue page', :js do
 
           visit project_issue_path(project, issue)
 
-          expect(page).to have_content('created branch 1-cherry-coloured-funk')
+          expect(page).to have_content("created merge request !1 to address this issue")
           expect(page).to have_content('mentioned in merge request !1')
         end
 
@@ -106,7 +106,7 @@ describe 'User creates branch and merge request on issue page', :js do
 
           visit project_issue_path(project, issue)
 
-          expect(page).to have_content('created branch custom-branch-name')
+          expect(page).to have_content("created merge request !1 to address this issue")
           expect(page).to have_content('mentioned in merge request !1')
         end
 
diff --git a/spec/features/issues/user_uses_quick_actions_spec.rb b/spec/features/issues/user_uses_quick_actions_spec.rb
index 5926e442f24..27cffdc5f8b 100644
--- a/spec/features/issues/user_uses_quick_actions_spec.rb
+++ b/spec/features/issues/user_uses_quick_actions_spec.rb
@@ -303,5 +303,63 @@ describe 'Issues > User uses quick actions', :js do
         end
       end
     end
+
+    describe 'create a merge request starting from an issue' do
+      let(:project) { create(:project, :public, :repository) }
+      let(:issue) { create(:issue, project: project) }
+
+      def expect_mr_quickaction(success)
+        expect(page).to have_content 'Commands applied'
+
+        if success
+          expect(page).to have_content 'created merge request'
+        else
+          expect(page).not_to have_content 'created merge request'
+        end
+      end
+
+      it "doesn't create a merge request when the branch name is invalid" do
+        add_note("/create_merge_request invalid branch name")
+
+        wait_for_requests
+
+        expect_mr_quickaction(false)
+      end
+
+      it "doesn't create a merge request when a branch with that name already exists" do
+        add_note("/create_merge_request feature")
+
+        wait_for_requests
+
+        expect_mr_quickaction(false)
+      end
+
+      it 'creates a new merge request using issue iid and title as branch name when the branch name is empty' do
+        add_note("/create_merge_request")
+
+        wait_for_requests
+
+        expect_mr_quickaction(true)
+
+        created_mr = project.merge_requests.last
+        expect(created_mr.source_branch).to eq(issue.to_branch_name)
+
+        visit project_merge_request_path(project, created_mr)
+        expect(page).to have_content %{WIP: Resolve "#{issue.title}"}
+      end
+
+      it 'creates a merge request using the given branch name' do
+        branch_name = '1-feature'
+        add_note("/create_merge_request #{branch_name}")
+
+        expect_mr_quickaction(true)
+
+        created_mr = project.merge_requests.last
+        expect(created_mr.source_branch).to eq(branch_name)
+
+        visit project_merge_request_path(project, created_mr)
+        expect(page).to have_content %{WIP: Resolve "#{issue.title}"}
+      end
+    end
   end
 end
diff --git a/spec/services/merge_requests/create_from_issue_service_spec.rb b/spec/services/merge_requests/create_from_issue_service_spec.rb
index b1882df732d..393299cce00 100644
--- a/spec/services/merge_requests/create_from_issue_service_spec.rb
+++ b/spec/services/merge_requests/create_from_issue_service_spec.rb
@@ -61,7 +61,15 @@ describe MergeRequests::CreateFromIssueService do
       expect(project.repository.branch_exists?(custom_source_branch)).to be_truthy
     end
 
-    it 'creates a system note' do
+    it 'creates the new_merge_request system note' do
+      expect(SystemNoteService).to receive(:new_merge_request).with(issue, project, user, instance_of(MergeRequest))
+
+      service.execute
+    end
+
+    it 'creates the new_issue_branch system note when the branch could be created but the merge_request cannot be created' do
+      project.project_feature.update!(merge_requests_access_level: ProjectFeature::DISABLED)
+
       expect(SystemNoteService).to receive(:new_issue_branch).with(issue, project, user, issue.to_branch_name)
 
       service.execute
diff --git a/spec/services/quick_actions/interpret_service_spec.rb b/spec/services/quick_actions/interpret_service_spec.rb
index 5a7cafcb60f..938764f40b0 100644
--- a/spec/services/quick_actions/interpret_service_spec.rb
+++ b/spec/services/quick_actions/interpret_service_spec.rb
@@ -1222,6 +1222,37 @@ describe QuickActions::InterpretService do
       expect(commands).to be_empty
       expect(text).to eq("#{described_class::SHRUG}\n/close")
     end
+
+    context '/create_merge_request command' do
+      let(:branch_name) { '1-feature' }
+      let(:content) { "/create_merge_request #{branch_name}" }
+      let(:issuable) { issue }
+
+      context 'if issuable is not an Issue' do
+        let(:issuable) { merge_request }
+
+        it_behaves_like 'empty command'
+      end
+
+      context "when logged user cannot create_merge_requests in the project" do
+        let(:project) { create(:project, :archived) }
+
+        it_behaves_like 'empty command'
+      end
+
+      context 'when logged user cannot push code to the project' do
+        let(:project) { create(:project, :private) }
+        let(:service) { described_class.new(project, create(:user)) }
+
+        it_behaves_like 'empty command'
+      end
+
+      it 'populates create_merge_request with branch_name and issue iid' do
+        _, updates = service.execute(content, issuable)
+
+        expect(updates).to eq(create_merge_request: { branch_name: branch_name, issue_iid: issuable.iid })
+      end
+    end
   end
 
   describe '#explain' do
@@ -1473,5 +1504,27 @@ describe QuickActions::InterpretService do
         end
       end
     end
+
+    describe 'create a merge request' do
+      context 'with no branch name' do
+        let(:content) { '/create_merge_request' }
+
+        it 'uses the default branch name' do
+          _, explanations = service.explain(content, issue)
+
+          expect(explanations).to eq(['Creates a branch and a merge request to resolve this issue'])
+        end
+      end
+
+      context 'with a branch name' do
+        let(:content) { '/create_merge_request foo' }
+
+        it 'uses the given branch name' do
+          _, explanations = service.explain(content, issue)
+
+          expect(explanations).to eq(["Creates branch 'foo' and a merge request to resolve this issue"])
+        end
+      end
+    end
   end
 end
diff --git a/spec/services/system_note_service_spec.rb b/spec/services/system_note_service_spec.rb
index a18126ee339..0fbfcb34e50 100644
--- a/spec/services/system_note_service_spec.rb
+++ b/spec/services/system_note_service_spec.rb
@@ -432,6 +432,20 @@ describe SystemNoteService do
     end
   end
 
+  describe '.new_merge_request' do
+    subject { described_class.new_merge_request(noteable, project, author, merge_request) }
+
+    let(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+
+    it_behaves_like 'a system note' do
+      let(:action) { 'merge' }
+    end
+
+    it 'sets the new merge request note text' do
+      expect(subject.note).to eq("created merge request #{merge_request.to_reference} to address this issue")
+    end
+  end
+
   describe '.cross_reference' do
     subject { described_class.cross_reference(noteable, mentioner, author) }