Allow project owners to set up forking relation through API

Before this change only GitLab admins where allowed to set up forking
relation through the API. This changes that so project owners can
do this too.

Closes gitlab-org/gitlab-ce#40550.

changelogs/unreleased/tc-api-fork-owners.yml

+---
+title: Allow project owners to set up forking relation through API
+merge_request: 18104
+author:
+type: changed

doc/api/projects.md

@@ -1413,9 +1413,9 @@ DELETE /projects/:id/hooks/:hook_id
 Note the JSON response differs if the hook is available or not. If the project hook
 is available before it is returned in the JSON response or an empty response is returned.
 
-## Admin fork relation
+## Fork relationship
 
-Allows modification of the forked relationship between existing projects. Available only for admins.
+Allows modification of the forked relationship between existing projects. Available only for project owners and admins.
 
 ### Create a forked from/to relation between existing projects
 

lib/api/projects.rb

@@ -386,7 +386,7 @@ module API
         requires :forked_from_id, type: String, desc: 'The ID of the project it was forked from'
       end
       post ":id/fork/:forked_from_id" do
-        authenticated_as_admin!
+        authorize! :admin_project, user_project
 
         fork_from_project = find_project!(params[:forked_from_id])
 

spec/requests/api/projects_spec.rb

@@ -402,7 +402,7 @@ describe API::Projects do
 
       context 'and with min_access_level' do
         before do
-          project2.add_master(user2)
+          project2.add_maintainer(user2)
           project3.add_developer(user2)
           project4.add_reporter(user2)
         end
@@ -1121,31 +1121,68 @@ describe API::Projects do
   describe 'fork management' do
     let(:project_fork_target) { create(:project) }
     let(:project_fork_source) { create(:project, :public) }
+    let(:private_project_fork_source) { create(:project, :private) }
 
     describe 'POST /projects/:id/fork/:forked_from_id' do
-      let(:new_project_fork_source) { create(:project, :public) }
+      context 'user is a developer' do
+        before do
+          project_fork_target.add_developer(user)
+        end
 
-      it "is not available for non admin users" do
+        it 'denies project to be forked from an existing project' do
           post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", user)
+
           expect(response).to have_gitlab_http_status(403)
         end
+      end
+
+      it 'refreshes the forks count cache' do
+        expect(project_fork_source.forks_count).to be_zero
+      end
+
+      context 'user is maintainer' do
+        before do
+          project_fork_target.add_maintainer(user)
+        end
 
         it 'allows project to be forked from an existing project' do
-        expect(project_fork_target.forked?).not_to be_truthy
-        post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", admin)
-        expect(response).to have_gitlab_http_status(201)
+          expect(project_fork_target).not_to be_forked
+
+          post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", user)
           project_fork_target.reload
+
+          expect(response).to have_gitlab_http_status(201)
           expect(project_fork_target.forked_from_project.id).to eq(project_fork_source.id)
-        expect(project_fork_target.forked_project_link).not_to be_nil
-        expect(project_fork_target.forked?).to be_truthy
+          expect(project_fork_target.forked_project_link).to be_present
+          expect(project_fork_target).to be_forked
         end
 
-      it 'refreshes the forks count cache' do
-        expect(project_fork_source.forks_count).to be_zero
+        it 'denies project to be forked from a private project' do
+          post api("/projects/#{project_fork_target.id}/fork/#{private_project_fork_source.id}", user)
+
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+
+      context 'user is admin' do
+        it 'allows project to be forked from an existing project' do
+          expect(project_fork_target).not_to be_forked
 
           post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", admin)
 
-        expect(project_fork_source.forks_count).to eq(1)
+          expect(response).to have_gitlab_http_status(201)
+        end
+
+        it 'allows project to be forked from a private project' do
+          post api("/projects/#{project_fork_target.id}/fork/#{private_project_fork_source.id}", admin)
+
+          expect(response).to have_gitlab_http_status(201)
+        end
+
+        it 'refreshes the forks count cachce' do
+          expect do
+            post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", admin)
+          end.to change(project_fork_source, :forks_count).by(1)
         end
 
         it 'fails if forked_from project which does not exist' do
@@ -1154,14 +1191,17 @@ describe API::Projects do
         end
 
         it 'fails with 409 if already forked' do
-        post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", admin)
+          other_project_fork_source = create(:project, :public)
+
+          Projects::ForkService.new(project_fork_source, admin).execute(project_fork_target)
+
+          post api("/projects/#{project_fork_target.id}/fork/#{other_project_fork_source.id}", admin)
           project_fork_target.reload
-        expect(project_fork_target.forked_from_project.id).to eq(project_fork_source.id)
-        post api("/projects/#{project_fork_target.id}/fork/#{new_project_fork_source.id}", admin)
+
           expect(response).to have_gitlab_http_status(409)
-        project_fork_target.reload
           expect(project_fork_target.forked_from_project.id).to eq(project_fork_source.id)
-        expect(project_fork_target.forked?).to be_truthy
+          expect(project_fork_target).to be_forked
+        end
       end
     end
 
@@ -1183,8 +1223,8 @@ describe API::Projects do
           before do
             post api("/projects/#{project_fork_target.id}/fork/#{project_fork_source.id}", admin)
             project_fork_target.reload
-            expect(project_fork_target.forked_from_project).not_to be_nil
-            expect(project_fork_target.forked?).to be_truthy
+            expect(project_fork_target.forked_from_project).to be_present
+            expect(project_fork_target).to be_forked
           end
 
           it 'makes forked project unforked' do
@@ -1193,7 +1233,7 @@ describe API::Projects do
             expect(response).to have_gitlab_http_status(204)
             project_fork_target.reload
             expect(project_fork_target.forked_from_project).to be_nil
-            expect(project_fork_target.forked?).not_to be_truthy
+            expect(project_fork_target).not_to be_forked
           end
 
           it_behaves_like '412 response' do
@@ -1228,8 +1268,8 @@ describe API::Projects do
         before do
           post api("/projects/#{private_fork.id}/fork/#{project_fork_source.id}", admin)
           private_fork.reload
-          expect(private_fork.forked_from_project).not_to be_nil
-          expect(private_fork.forked?).to be_truthy
+          expect(private_fork.forked_from_project).to be_present
+          expect(private_fork).to be_forked
           project_fork_source.reload
           expect(project_fork_source.forks.length).to eq(1)
           expect(project_fork_source.forks).to include(private_fork)