Merge branch '218609-bitbucket-server-importer-by-slug' into 'master'

Add user mapping by username to Bitbucket Server importer

Closes #218609

See merge request gitlab-org/gitlab!36885

changelogs/unreleased/218609-bitbucket-server-importer-by-slug.yml

+---
+title: Add user mapping by username when importing projects for Bitbucket Server importer
+merge_request: 36885
+author:
+type: added

config/feature_flags/development/bitbucket_server_user_mapping_by_username.yml

+---
+name: bitbucket_server_user_mapping_by_username
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/36885
+rollout_issue_url:
+group: group::import
+type: development
+default_enabled: false

doc/user/project/import/bitbucket_server.md

@@ -62,6 +62,25 @@ The importer will create any new namespaces (groups) if they don't exist or in
 the case the namespace is taken, the repository will be imported under the user's
 namespace that started the import process.
 
+#### User assignment by username
+
+Alternatively, user assignment by username is available behind a `bitbucket_server_user_mapping_by_username` feature flag.
+The importer will try to find a user in the GitLab user database using author's `username` or `slug` or `displayName`.
+Falls back to author's `email` if user is not found by username.
+Similarly to user assignment by email, if no such user is available, the project creator is set as the author.
+
+To enable or disable user assignment by username:
+
+Start a [Rails console](../../../administration/troubleshooting/debug.md#starting-a-rails-console-session).
+
+```ruby
+# Enable
+Feature.enable(:bitbucket_server_user_mapping_by_username)
+
+# Disable
+Feature.disable(:bitbucket_server_user_mapping_by_username)
+```
+
 ## Importing your Bitbucket repositories
 
 1. Sign in to GitLab and go to your dashboard.

lib/bitbucket_server/representation/comment.rb

@@ -38,6 +38,8 @@ module BitbucketServer
       end
 
       def author_username
+        author['username'] ||
+          author['slug'] ||
           author['displayName']
       end
 

lib/bitbucket_server/representation/pull_request.rb

@@ -11,6 +11,12 @@ module BitbucketServer
         raw.dig('author', 'user', 'emailAddress')
       end
 
+      def author_username
+        raw.dig('author', 'user', 'username') ||
+          raw.dig('author', 'user', 'slug') ||
+          raw.dig('author', 'user', 'displayName')
+      end
+
       def description
         raw['description']
       end

lib/gitlab/bitbucket_server_import/importer.rb

@@ -61,17 +61,18 @@ module Gitlab
         }.to_json)
       end
 
-      def gitlab_user_id(email)
-        find_user_id(email) || project.creator_id
-      end
+      def find_user_id(by:, value:)
+        return unless value
 
-      def find_user_id(email)
-        return unless email
+        return users[value] if users.key?(value)
 
-        return users[email] if users.key?(email)
+        user = if by == :email
+                 User.find_by_any_email(value, confirmed: true)
+               else
+                 User.find_by_username(value)
+               end
 
-        user = User.find_by_any_email(email, confirmed: true)
-        users[email] = user&.id
+        users[value] = user&.id
 
         user&.id
       end
@@ -197,9 +198,8 @@ module Gitlab
         log_info(stage: 'import_bitbucket_pull_requests', message: 'starting', iid: pull_request.iid)
 
         description = ''
-        description += @formatter.author_line(pull_request.author) unless find_user_id(pull_request.author_email)
+        description += author_line(pull_request)
         description += pull_request.description if pull_request.description
-        author_id = gitlab_user_id(pull_request.author_email)
 
         attributes = {
           iid: pull_request.iid,
@@ -212,7 +212,7 @@ module Gitlab
           target_branch: Gitlab::Git.ref_name(pull_request.target_branch_name),
           target_branch_sha: pull_request.target_branch_sha,
           state_id: MergeRequest.available_states[pull_request.state],
-          author_id: author_id,
+          author_id: author_id(pull_request),
           created_at: pull_request.created_at,
           updated_at: pull_request.updated_at
         }
@@ -254,7 +254,7 @@ module Gitlab
 
         committer = merge_event.committer_email
 
-        user_id = gitlab_user_id(committer)
+        user_id = find_user_id(by: :email, value: committer) || project.creator_id
         timestamp = merge_event.merge_timestamp
         merge_request.update({ merge_commit_sha: merge_event.merge_commit })
         metric = MergeRequest::Metrics.find_or_initialize_by(merge_request: merge_request)
@@ -353,7 +353,7 @@ module Gitlab
       end
 
       def pull_request_comment_attributes(comment)
-        author = find_user_id(comment.author_email)
+        author = uid(comment)
         note = ''
 
         unless author
@@ -397,6 +397,23 @@ module Gitlab
       def metrics
         @metrics ||= Gitlab::Import::Metrics.new(:bitbucket_server_importer, @project)
       end
+
+      def author_line(rep_object)
+        return '' if uid(rep_object)
+
+        @formatter.author_line(rep_object.author)
+      end
+
+      def author_id(rep_object)
+        uid(rep_object) || project.creator_id
+      end
+
+      def uid(rep_object)
+        find_user_id(by: :email, value: rep_object.author_email) unless Feature.enabled?(:bitbucket_server_user_mapping_by_username)
+
+        find_user_id(by: :username, value: rep_object.author_username) ||
+          find_user_id(by: :email, value: rep_object.author_email)
+      end
     end
   end
 end

spec/fixtures/importers/bitbucket_server/activities.json

@@ -20,7 +20,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "comments": [
@@ -38,7 +39,8 @@
                                 ]
                             },
                             "name": "root",
-                            "slug": "root",
+                            "slug": "slug",
+                            "username": "username",
                             "type": "NORMAL"
                         },
                         "comments": [
@@ -56,7 +58,8 @@
                                         ]
                                     },
                                     "name": "root",
-                                    "slug": "root",
+                                    "slug": "slug",
+                                    "username": "username",
                                     "type": "NORMAL"
                                 },
                                 "comments": [],
@@ -85,7 +88,8 @@
                                                     ]
                                                 },
                                                 "name": "root",
-                                                "slug": "root",
+                                                "slug": "slug",
+                                                "username": "username",
                                                 "type": "NORMAL"
                                             },
                                             "createdDate": 1530164016725,
@@ -115,7 +119,8 @@
                                                 ]
                                             },
                                             "name": "root",
-                                            "slug": "root",
+                                            "slug": "slug",
+                                            "username": "username",
                                             "type": "NORMAL"
                                         },
                                         "createdDate": 1530164026000,
@@ -147,7 +152,8 @@
                                         ]
                                     },
                                     "name": "root",
-                                    "slug": "root",
+                                    "slug": "slug",
+                                    "username": "username",
                                     "type": "NORMAL"
                                 },
                                 "comments": [],
@@ -194,7 +200,8 @@
                                 ]
                             },
                             "name": "root",
-                            "slug": "root",
+                            "slug": "slug",
+                            "username": "username",
                             "type": "NORMAL"
                         },
                         "comments": [],
@@ -363,7 +370,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -383,7 +391,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "comments": [],
@@ -543,7 +552,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -563,7 +573,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "comments": [
@@ -581,7 +592,8 @@
                                 ]
                             },
                             "name": "root",
-                            "slug": "root",
+                            "slug": "slug",
+                            "username": "username",
                             "type": "NORMAL"
                         },
                         "comments": [
@@ -599,7 +611,8 @@
                                         ]
                                     },
                                     "name": "root",
-                                    "slug": "root",
+                                    "slug": "slug",
+                                    "username": "username",
                                     "type": "NORMAL"
                                 },
                                 "comments": [],
@@ -789,7 +802,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -809,7 +823,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "comments": [],
@@ -843,7 +858,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -863,7 +879,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "authorTimestamp": 1529727872000,
@@ -880,7 +897,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "committerTimestamp": 1529727872000,
@@ -951,7 +969,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -971,7 +990,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "comments": [
@@ -989,7 +1009,8 @@
                                 ]
                             },
                             "name": "root",
-                            "slug": "root",
+                            "slug": "slug",
+                            "username": "username",
                             "type": "NORMAL"
                         },
                         "comments": [],
@@ -1038,7 +1059,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -1058,7 +1080,8 @@
                         ]
                     },
                     "name": "root",
-                    "slug": "root",
+                    "slug": "slug",
+                    "username": "username",
                     "type": "NORMAL"
                 },
                 "comments": [],
@@ -1092,7 +1115,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         },
@@ -1113,7 +1137,8 @@
                     ]
                 },
                 "name": "root",
-                "slug": "root",
+                "slug": "slug",
+                "username": "username",
                 "type": "NORMAL"
             }
         }

spec/fixtures/importers/bitbucket_server/pull_request.json

@@ -5,8 +5,9 @@
       "status":"UNAPPROVED",
       "user":{
          "active":true,
-         "displayName":"root",
+         "displayName":"displayName",
          "emailAddress":"joe.montana@49ers.com",
+         "username": "username",
          "id":1,
          "links":{
             "self":[
@@ -16,7 +17,7 @@
             ]
          },
          "name":"root",
-         "slug":"root",
+         "slug":"slug",
          "type":"NORMAL"
       }
    },

spec/lib/bitbucket_server/representation/comment_spec.rb

@@ -13,7 +13,30 @@ RSpec.describe BitbucketServer::Representation::Comment do
   end
 
   describe '#author_username' do
-    it { expect(subject.author_username).to eq('root' ) }
+    it 'returns username' do
+      expect(subject.author_username).to eq('username')
+    end
+
+    context 'when username is absent' do
+      before do
+        comment['comment']['author'].delete('username')
+      end
+
+      it 'returns slug' do
+        expect(subject.author_username).to eq('slug')
+      end
+    end
+
+    context 'when slug and username are absent' do
+      before do
+        comment['comment']['author'].delete('username')
+        comment['comment']['author'].delete('slug')
+      end
+
+      it 'returns displayName' do
+        expect(subject.author_username).to eq('root')
+      end
+    end
   end
 
   describe '#author_email' do

spec/lib/bitbucket_server/representation/pull_request_spec.rb

@@ -15,6 +15,33 @@ RSpec.describe BitbucketServer::Representation::PullRequest do
     it { expect(subject.author_email).to eq('joe.montana@49ers.com') }
   end
 
+  describe '#author_username' do
+    it 'returns username' do
+      expect(subject.author_username).to eq('username')
+    end
+
+    context 'when username is absent' do
+      before do
+        sample_data['author']['user'].delete('username')
+      end
+
+      it 'returns slug' do
+        expect(subject.author_username).to eq('slug')
+      end
+    end
+
+    context 'when slug and username are absent' do
+      before do
+        sample_data['author']['user'].delete('username')
+        sample_data['author']['user'].delete('slug')
+      end
+
+      it 'returns displayName' do
+        expect(subject.author_username).to eq('displayName')
+      end
+    end
+  end
+
   describe '#description' do
     it { expect(subject.description).to eq('Test') }
   end

spec/lib/gitlab/bitbucket_server_import/importer_spec.rb

@@ -6,9 +6,10 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
   include ImportSpecHelper
 
   let(:import_url) { 'http://my-bitbucket' }
-  let(:user) { 'bitbucket' }
+  let(:bitbucket_user) { 'bitbucket' }
+  let(:project_creator) { create(:user, username: 'project_creator', email: 'project_creator@example.org') }
   let(:password) { 'test' }
-  let(:project) { create(:project, :repository, import_url: import_url) }
+  let(:project) { create(:project, :repository, import_url: import_url, creator: project_creator) }
   let(:now) { Time.now.utc.change(usec: 0) }
   let(:project_key) { 'TEST' }
   let(:repo_slug) { 'rouge' }
@@ -19,7 +20,7 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
   before do
     data = project.create_or_update_import_data(
       data: { project_key: project_key, repo_slug: repo_slug },
-      credentials: { base_uri: import_url, user: user, password: password }
+      credentials: { base_uri: import_url, user: bitbucket_user, password: password }
     )
     data.save
     project.save
@@ -51,12 +52,11 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
   end
 
   describe '#import_pull_requests' do
-    before do
-      allow(subject).to receive(:import_repository)
-      allow(subject).to receive(:delete_temp_branches)
-      allow(subject).to receive(:restore_branches)
+    let(:pull_request_author) { create(:user, username: 'pull_request_author', email: 'pull_request_author@example.org') }
+    let(:note_author) { create(:user, username: 'note_author', email: 'note_author@example.org') }
 
-      pull_request = instance_double(
+    let(:pull_request) do
+      instance_double(
         BitbucketServer::Representation::PullRequest,
         iid: 10,
         source_branch_sha: sample.commits.last,
@@ -67,65 +67,172 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
         description: 'This is a test pull request',
         state: 'merged',
         author: 'Test Author',
-        author_email: project.owner.email,
+        author_email: pull_request_author.email,
+        author_username: pull_request_author.username,
         created_at: Time.now,
         updated_at: Time.now,
         raw: {},
         merged?: true)
+    end
 
-      allow(subject.client).to receive(:pull_requests).and_return([pull_request])
-
-      @merge_event = instance_double(
+    let(:merge_event) do
+      instance_double(
         BitbucketServer::Representation::Activity,
         comment?: false,
         merge_event?: true,
-        committer_email: project.owner.email,
+        committer_email: pull_request_author.email,
         merge_timestamp: now,
         merge_commit: '12345678'
       )
+    end
 
-      @pr_note = instance_double(
+    let(:pr_note) do
+      instance_double(
         BitbucketServer::Representation::Comment,
         note: 'Hello world',
-        author_email: 'unknown@gmail.com',
-        author_username: 'The Flash',
+        author_email: note_author.email,
+        author_username: note_author.username,
         comments: [],
         created_at: now,
         updated_at: now,
         parent_comment: nil)
+    end
 
-      @pr_comment = instance_double(
+    let(:pr_comment) do
+      instance_double(
         BitbucketServer::Representation::Activity,
         comment?: true,
         inline_comment?: false,
         merge_event?: false,
-        comment: @pr_note)
+        comment: pr_note)
+    end
+
+    before do
+      allow(subject).to receive(:import_repository)
+      allow(subject).to receive(:delete_temp_branches)
+      allow(subject).to receive(:restore_branches)
+
+      allow(subject.client).to receive(:pull_requests).and_return([pull_request])
     end
 
     it 'imports merge event' do
-      expect(subject.client).to receive(:activities).and_return([@merge_event])
+      expect(subject.client).to receive(:activities).and_return([merge_event])
 
       expect { subject.execute }.to change { MergeRequest.count }.by(1)
 
       merge_request = MergeRequest.first
-      expect(merge_request.metrics.merged_by).to eq(project.owner)
-      expect(merge_request.metrics.merged_at).to eq(@merge_event.merge_timestamp)
+      expect(merge_request.metrics.merged_by).to eq(pull_request_author)
+      expect(merge_request.metrics.merged_at).to eq(merge_event.merge_timestamp)
       expect(merge_request.merge_commit_sha).to eq('12345678')
       expect(merge_request.state_id).to eq(3)
     end
 
+    describe 'pull request author user mapping' do
+      before do
+        allow(subject.client).to receive(:activities).and_return([merge_event])
+      end
+
+      shared_examples 'imports pull requests' do
+        it 'maps user' do
+          expect { subject.execute }.to change { MergeRequest.count }.by(1)
+
+          merge_request = MergeRequest.first
+          expect(merge_request.author).to eq(pull_request_author)
+        end
+      end
+
+      context 'when bitbucket_server_user_mapping_by_username feature flag is disabled' do
+        before do
+          stub_feature_flags(bitbucket_server_user_mapping_by_username: false)
+        end
+
+        include_examples 'imports pull requests'
+      end
+
+      context 'when bitbucket_server_user_mapping_by_username feature flag is enabled' do
+        before do
+          stub_feature_flags(bitbucket_server_user_mapping_by_username: true)
+        end
+
+        include_examples 'imports pull requests' do
+          context 'when username is not present' do
+            before do
+              allow(pull_request).to receive(:author_username).and_return(nil)
+            end
+
+            it 'maps by email' do
+              expect { subject.execute }.to change { MergeRequest.count }.by(1)
+
+              merge_request = MergeRequest.first
+              expect(merge_request.author).to eq(pull_request_author)
+            end
+          end
+        end
+      end
+
+      context 'when user is not found' do
+        before do
+          allow(pull_request).to receive(:author_username).and_return(nil)
+          allow(pull_request).to receive(:author_email).and_return(nil)
+        end
+
+        it 'maps importer user' do
+          expect { subject.execute }.to change { MergeRequest.count }.by(1)
+
+          merge_request = MergeRequest.first
+          expect(merge_request.author).to eq(project_creator)
+        end
+      end
+    end
+
+    describe 'comments' do
+      shared_examples 'imports comments' do
         it 'imports comments' do
-      expect(subject.client).to receive(:activities).and_return([@pr_comment])
+          expect(subject.client).to receive(:activities).and_return([pr_comment])
+
+          expect { subject.execute }.to change { MergeRequest.count }.by(1)
+
+          merge_request = MergeRequest.first
+          expect(merge_request.notes.count).to eq(1)
+          note = merge_request.notes.first
+          expect(note.note).to end_with(pr_note.note)
+          expect(note.author).to eq(note_author)
+          expect(note.created_at).to eq(pr_note.created_at)
+          expect(note.updated_at).to eq(pr_note.created_at)
+        end
+      end
+
+      context 'when bitbucket_server_user_mapping_by_username feature flag is disabled' do
+        before do
+          stub_feature_flags(bitbucket_server_user_mapping_by_username: false)
+        end
+
+        include_examples 'imports comments'
+      end
+
+      context 'when bitbucket_server_user_mapping_by_username feature flag is enabled' do
+        before do
+          stub_feature_flags(bitbucket_server_user_mapping_by_username: true)
+        end
+
+        include_examples 'imports comments'
+
+        context 'when username is not present' do
+          before do
+            allow(pr_note).to receive(:author_username).and_return(nil)
+            allow(subject.client).to receive(:activities).and_return([pr_comment])
+          end
 
+          it 'maps by email' do
             expect { subject.execute }.to change { MergeRequest.count }.by(1)
 
             merge_request = MergeRequest.first
             expect(merge_request.notes.count).to eq(1)
             note = merge_request.notes.first
-      expect(note.note).to end_with(@pr_note.note)
-      expect(note.author).to eq(project.owner)
-      expect(note.created_at).to eq(@pr_note.created_at)
-      expect(note.updated_at).to eq(@pr_note.created_at)
+            expect(note.author).to eq(note_author)
+          end
+        end
+      end
     end
 
     context 'metrics' do
@@ -135,7 +242,7 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
       before do
         allow(Gitlab::Metrics).to receive(:counter) { counter }
         allow(Gitlab::Metrics).to receive(:histogram) { histogram }
-        allow(subject.client).to receive(:activities).and_return([@merge_event])
+        allow(subject.client).to receive(:activities).and_return([merge_event])
       end
 
       it 'counts and measures duration of imported projects' do
@@ -170,17 +277,23 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
       end
     end
 
-    it 'imports threaded discussions' do
-      reply = instance_double(
+    describe 'threaded discussions' do
+      let(:reply_author) { create(:user, username: 'reply_author', email: 'reply_author@example.org') }
+      let(:inline_note_author) { create(:user, username: 'inline_note_author', email: 'inline_note_author@example.org') }
+
+      let(:reply) do
+        instance_double(
           BitbucketServer::Representation::PullRequestComment,
-        author_email: 'someuser@gitlab.com',
-        author_username: 'Batman',
+          author_email: reply_author.email,
+          author_username: reply_author.username,
           note: 'I agree',
           created_at: now,
           updated_at: now)
+      end
 
       # https://gitlab.com/gitlab-org/gitlab-test/compare/c1acaa58bbcbc3eafe538cb8274ba387047b69f8...5937ac0a7beb003549fc5fd26fc247ad
-      inline_note = instance_double(
+      let(:inline_note) do
+        instance_double(
           BitbucketServer::Representation::PullRequestComment,
           file_type: 'ADDED',
           from_sha: sample.commits.first,
@@ -189,24 +302,30 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
           old_pos: nil,
           new_pos: 4,
           note: 'Hello world',
-        author_email: 'unknown@gmail.com',
-        author_username: 'Superman',
+          author_email: inline_note_author.email,
+          author_username: inline_note_author.username,
           comments: [reply],
           created_at: now,
           updated_at: now,
           parent_comment: nil)
+      end
 
-      allow(reply).to receive(:parent_comment).and_return(inline_note)
-
-      inline_comment = instance_double(
+      let(:inline_comment) do
+        instance_double(
           BitbucketServer::Representation::Activity,
           comment?: true,
           inline_comment?: true,
           merge_event?: false,
           comment: inline_note)
+      end
 
-      expect(subject.client).to receive(:activities).and_return([inline_comment])
+      before do
+        allow(reply).to receive(:parent_comment).and_return(inline_note)
+        allow(subject.client).to receive(:activities).and_return([inline_comment])
+      end
 
+      shared_examples 'imports threaded discussions' do
+        it 'imports threaded discussions' do
           expect { subject.execute }.to change { MergeRequest.count }.by(1)
 
           merge_request = MergeRequest.first
@@ -224,12 +343,12 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
           expect(start_note.position.head_sha).to eq(inline_note.to_sha)
           expect(start_note.position.old_line).to be_nil
           expect(start_note.position.new_line).to eq(inline_note.new_pos)
+          expect(start_note.author).to eq(inline_note_author)
 
           reply_note = notes.last
           # Make sure author and reply context is included
-      expect(reply_note.note).to start_with("*By #{reply.author_username} (#{reply.author_email})*\n\n")
-      expect(reply_note.note).to end_with("> #{inline_note.note}\n\n#{reply.note}")
-      expect(reply_note.author).to eq(project.owner)
+          expect(reply_note.note).to start_with("> #{inline_note.note}\n\n#{reply.note}")
+          expect(reply_note.author).to eq(reply_author)
           expect(reply_note.created_at).to eq(reply.created_at)
           expect(reply_note.updated_at).to eq(reply.created_at)
           expect(reply_note.position.base_sha).to eq(inline_note.from_sha)
@@ -238,6 +357,58 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
           expect(reply_note.position.old_line).to be_nil
           expect(reply_note.position.new_line).to eq(inline_note.new_pos)
         end
+      end
+
+      context 'when bitbucket_server_user_mapping_by_username feature flag is disabled' do
+        before do
+          stub_feature_flags(bitbucket_server_user_mapping_by_username: false)
+        end
+
+        include_examples 'imports threaded discussions'
+      end
+
+      context 'when bitbucket_server_user_mapping_by_username feature flag is enabled' do
+        before do
+          stub_feature_flags(bitbucket_server_user_mapping_by_username: true)
+        end
+
+        include_examples 'imports threaded discussions' do
+          context 'when username is not present' do
+            before do
+              allow(reply).to receive(:author_username).and_return(nil)
+              allow(inline_note).to receive(:author_username).and_return(nil)
+            end
+
+            it 'maps by email' do
+              expect { subject.execute }.to change { MergeRequest.count }.by(1)
+
+              notes = MergeRequest.first.notes.order(:id).to_a
+
+              expect(notes.first.author).to eq(inline_note_author)
+              expect(notes.last.author).to eq(reply_author)
+            end
+          end
+        end
+      end
+
+      context 'when user is not found' do
+        before do
+          allow(reply).to receive(:author_username).and_return(nil)
+          allow(reply).to receive(:author_email).and_return(nil)
+          allow(inline_note).to receive(:author_username).and_return(nil)
+          allow(inline_note).to receive(:author_email).and_return(nil)
+        end
+
+        it 'maps importer user' do
+          expect { subject.execute }.to change { MergeRequest.count }.by(1)
+
+          notes = MergeRequest.first.notes.order(:id).to_a
+
+          expect(notes.first.author).to eq(project_creator)
+          expect(notes.last.author).to eq(project_creator)
+        end
+      end
+    end
 
     it 'falls back to comments if diff comments fail to validate' do
       reply = instance_double(
@@ -312,6 +483,7 @@ RSpec.describe Gitlab::BitbucketServerImport::Importer do
         state: 'merged',
         author: 'Test Author',
         author_email: project.owner.email,
+        author_username: 'author',
         created_at: Time.now,
         updated_at: Time.now,
         merged?: true)