4 files changed, 18 insertions, 6 deletions
diff --git a/lib/gitlab/github_import/branch_formatter.rb b/lib/gitlab/github_import/branch_formatter.rb
index 0a8d05b5fe1..5d29e698b27 100644
--- a/lib/gitlab/github_import/branch_formatter.rb
+++ b/lib/gitlab/github_import/branch_formatter.rb
@@ -18,7 +18,7 @@ module Gitlab
       end
 
       def commit_exists?
-        project.repository.commit(sha).present?
+        project.repository.branch_names_contains(sha).include?(ref)
       end
 
       def short_id
diff --git a/lib/gitlab/github_import/importer.rb b/lib/gitlab/github_import/importer.rb
index d95ff4fd104..eea4a91f17d 100644
--- a/lib/gitlab/github_import/importer.rb
+++ b/lib/gitlab/github_import/importer.rb
@@ -171,6 +171,8 @@ module Gitlab
       end
 
       def clean_up_restored_branches(pull_request)
+        return if pull_request.opened?
+
         remove_branch(pull_request.source_branch_name) unless pull_request.source_branch_exists?
         remove_branch(pull_request.target_branch_name) unless pull_request.target_branch_exists?
       end
@@ -285,7 +287,7 @@ module Gitlab
       def fetch_resources(resource_type, *opts)
         return if imported?(resource_type)
 
-        opts.last.merge!(page: current_page(resource_type))
+        opts.last[:page] = current_page(resource_type)
 
         client.public_send(resource_type, *opts) do |resources|
           yield resources
diff --git a/lib/gitlab/github_import/issuable_formatter.rb b/lib/gitlab/github_import/issuable_formatter.rb
index 29fb0f9d333..27b171d6ddb 100644
--- a/lib/gitlab/github_import/issuable_formatter.rb
+++ b/lib/gitlab/github_import/issuable_formatter.rb
@@ -7,9 +7,7 @@ module Gitlab
         raise NotImplementedError
       end
 
-      def number
-        raw_data.number
-      end
+      delegate :number, to: :raw_data
 
       def find_condition
         { iid: number }
diff --git a/lib/gitlab/github_import/pull_request_formatter.rb b/lib/gitlab/github_import/pull_request_formatter.rb
index 4ea0200e89b..add7236e339 100644
--- a/lib/gitlab/github_import/pull_request_formatter.rb
+++ b/lib/gitlab/github_import/pull_request_formatter.rb
@@ -38,7 +38,11 @@ module Gitlab
 
       def source_branch_name
         @source_branch_name ||= begin
-          source_branch_exists? ? source_branch_ref : "pull/#{number}/#{source_branch_ref}"
+          if cross_project?
+            "pull/#{number}/#{source_branch_repo.full_name}/#{source_branch_ref}"
+          else
+            source_branch_exists? ? source_branch_ref : "pull/#{number}/#{source_branch_ref}"
+          end
         end
       end
 
@@ -52,6 +56,14 @@ module Gitlab
         end
       end
 
+      def cross_project?
+        source_branch.repo.id != target_branch.repo.id
+      end
+
+      def opened?
+        state == 'opened'
+      end
+
       private
 
       def state