Merge branch '273411-fj-fix-transient-error-in-branch-checking' into 'master'

Avoid branch name checking when creating a new snippet

See merge request gitlab-org/gitlab!48995

changelogs/unreleased/273411-fj-fix-transient-error-in-branch-checking.yml

+---
+title: Avoid branch name checking when creating a new snippet
+merge_request: 48995
+author:
+type: fixed

lib/gitlab/checks/snippet_check.rb

@@ -10,12 +10,13 @@ module Gitlab
       ATTRIBUTES = %i[oldrev newrev ref branch_name tag_name logger].freeze
       attr_reader(*ATTRIBUTES)
 
-      def initialize(change, default_branch:, logger:)
+      def initialize(change, default_branch:, root_ref:, logger:)
         @oldrev, @newrev, @ref = change.values_at(:oldrev, :newrev, :ref)
         @branch_name = Gitlab::Git.branch_name(@ref)
         @tag_name = Gitlab::Git.tag_name(@ref)
 
         @default_branch = default_branch
+        @root_ref = root_ref
         @logger = logger
         @logger.append_message("Running checks for ref: #{@branch_name || @tag_name}")
       end
@@ -34,8 +35,13 @@ module Gitlab
 
       private
 
+      # If the `root_ref` is not present means that this is the first commit to the
+      # repository and when the default branch is going to be created.
+      # We allow the first branch creation no matter the name because
+      # it can be even an imported snippet from an instance with a different
+      # default branch.
       def creation?
-        @branch_name != @default_branch && super
+        super && @root_ref && (@branch_name != @default_branch)
       end
     end
   end

lib/gitlab/git_access_snippet.rb

@@ -114,7 +114,7 @@ module Gitlab
 
     override :check_single_change_access
     def check_single_change_access(change, _skip_lfs_integrity_check: false)
-      Checks::SnippetCheck.new(change, default_branch: snippet.default_branch, logger: logger).validate!
+      Checks::SnippetCheck.new(change, default_branch: snippet.default_branch, root_ref: snippet.repository.root_ref, logger: logger).validate!
       Checks::PushFileCountCheck.new(change, repository: repository, limit: Snippet.max_file_limit, logger: logger).validate!
     rescue Checks::TimedLogger::TimeoutError
       raise TimeoutError, logger.full_message

spec/lib/gitlab/checks/snippet_check_spec.rb

@@ -13,7 +13,7 @@ RSpec.describe Gitlab::Checks::SnippetCheck do
   let(:creation) { false }
   let(:deletion) { false }
 
-  subject { Gitlab::Checks::SnippetCheck.new(changes, default_branch: default_branch, logger: logger) }
+  subject { Gitlab::Checks::SnippetCheck.new(changes, default_branch: default_branch, root_ref: snippet.repository.root_ref, logger: logger) }
 
   describe '#validate!' do
     it 'does not raise any error' do
@@ -45,10 +45,18 @@ RSpec.describe Gitlab::Checks::SnippetCheck do
         let(:branch_name) { 'feature' }
       end
 
-      context "when branch is 'master'" do
-        let(:ref) { 'refs/heads/master' }
+      context 'when branch is the same as the default branch' do
+        let(:ref) { "refs/heads/#{default_branch}" }
 
-        it "allows the operation" do
+        it 'allows the operation' do
+          expect { subject.validate! }.not_to raise_error
+        end
+      end
+
+      context 'when snippet has an empty repo' do
+        let_it_be(:snippet) { create(:personal_snippet, :empty_repo) }
+
+        it 'allows the operation' do
           expect { subject.validate! }.not_to raise_error
         end
       end