From a25fb529167f773a634f6034533c24513b15157f Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Fri, 19 May 2017 13:33:03 -0400
Subject: [PATCH 01/14] Upgrade Remove Source Branch checkbox UX.

---
 .../states/mr_widget_ready_to_merge.js        |  8 +++-
 .../stores/mr_widget_store.js                 |  4 +-
 .../issuable/form/_merge_params.html.haml     | 10 +++++
 spec/features/merge_requests/edit_mr_spec.rb  | 14 +++++++
 .../states/mr_widget_ready_to_merge_spec.js   | 37 ++++++++++++++++++-
 5 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js
index 74613a1089e..f30c831fd99 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js
@@ -13,7 +13,7 @@ export default {
   },
   data() {
     return {
-      removeSourceBranch: true,
+      removeSourceBranch: this.mr.shouldRemoveSourceBranch,
       mergeWhenBuildSucceeds: false,
       useCommitMessageWithDescription: false,
       setToMergeWhenPipelineSucceeds: false,
@@ -69,6 +69,9 @@ export default {
         || this.isMakingRequest
         || this.mr.preventMerge);
     },
+    isRemoveSourceBranchButtonDisabled() {
+      return this.isMergeButtonDisabled || !this.mr.canRemoveSourceBranch;
+    },
     shouldShowSquashBeforeMerge() {
       const { commitsCount, enableSquashBeforeMerge } = this.mr;
       return enableSquashBeforeMerge && commitsCount > 1;
@@ -252,8 +255,9 @@ export default {
       <template v-if="isMergeAllowed()">
         <label class="spacing">
           <input
+            id="remove-source-branch-input"
             v-model="removeSourceBranch"
-            :disabled="isMergeButtonDisabled"
+            :disabled="isRemoveSourceBranchButtonDisabled"
             type="checkbox"/> Remove source branch
         </label>
 
diff --git a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
index 06661b930e3..b3a0d9c0b11 100644
--- a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
+++ b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
@@ -11,6 +11,7 @@ export default class MergeRequestStore {
   setData(data) {
     const currentUser = data.current_user;
     const pipelineStatus = data.pipeline ? data.pipeline.details.status : null;
+    const mergeParams = data.merge_params || {};
 
     this.title = data.title;
     this.targetBranch = data.target_branch;
@@ -51,7 +52,8 @@ export default class MergeRequestStore {
     this.cancelAutoMergePath = data.cancel_merge_when_pipeline_succeeds_path;
     this.removeWIPPath = data.remove_wip_path;
     this.sourceBranchRemoved = !data.source_branch_exists;
-    this.shouldRemoveSourceBranch = (data.merge_params || {}).should_remove_source_branch || false;
+    this.shouldRemoveSourceBranch = mergeParams.should_remove_source_branch ||
+      mergeParams.force_remove_source_branch === "1" || false;
     this.onlyAllowMergeIfPipelineSucceeds = data.only_allow_merge_if_pipeline_succeeds || false;
     this.mergeWhenPipelineSucceeds = data.merge_when_pipeline_succeeds || false;
     this.mergePath = data.merge_path;
diff --git a/app/views/shared/issuable/form/_merge_params.html.haml b/app/views/shared/issuable/form/_merge_params.html.haml
index d23f79be2be..271150ed318 100644
--- a/app/views/shared/issuable/form/_merge_params.html.haml
+++ b/app/views/shared/issuable/form/_merge_params.html.haml
@@ -5,3 +5,13 @@
 
 -# This check is duplicated below, to avoid conflicts with EE.
 - return unless issuable.can_remove_source_branch?(current_user)
+
+.form-group
+  .col-sm-10.col-sm-offset-2
+    - if issuable.can_remove_source_branch?(current_user)
+      .checkbox
+        - initial_checkbox_value = issuable.merge_params.key?('force_remove_source_branch') ? issuable.force_remove_source_branch? : true
+        = label_tag 'merge_request[force_remove_source_branch]' do
+          = hidden_field_tag 'merge_request[force_remove_source_branch]', '0', id: nil
+          = check_box_tag 'merge_request[force_remove_source_branch]', '1', initial_checkbox_value
+          Remove source branch when merge request is accepted.
diff --git a/spec/features/merge_requests/edit_mr_spec.rb b/spec/features/merge_requests/edit_mr_spec.rb
index ec87a99b3ab..f4bfe7e19f6 100644
--- a/spec/features/merge_requests/edit_mr_spec.rb
+++ b/spec/features/merge_requests/edit_mr_spec.rb
@@ -29,6 +29,20 @@ feature 'Edit Merge Request', feature: true do
       expect(page).to have_content 'Someone edited the merge request the same time you did'
     end
 
+
+    it 'allows to unselect "Remove source branch"', js: true do
+      merge_request.update(merge_params: { 'force_remove_source_branch' => '1' })
+      expect(merge_request.merge_params['force_remove_source_branch']).to be_truthy
+
+      visit edit_namespace_project_merge_request_path(project.namespace, project, merge_request)
+      uncheck 'Remove source branch when merge request is accepted'
+
+      click_button 'Save changes'
+
+      expect(page).to have_unchecked_field 'remove-source-branch-input'
+      expect(page).to have_content 'Remove source branch'
+    end
+
     it 'should preserve description textarea height', js: true do
       long_description = %q(
         Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam ac ornare ligula, ut tempus arcu. Etiam ultricies accumsan dolor vitae faucibus. Donec at elit lacus. Mauris orci ante, aliquam quis lorem eget, convallis faucibus arcu. Aenean at pulvinar lacus. Ut viverra quam massa, molestie ornare tortor dignissim a. Suspendisse tristique pellentesque tellus, id lacinia metus elementum id. Nam tristique, arcu rhoncus faucibus viverra, lacus ipsum sagittis ligula, vitae convallis odio lacus a nibh. Ut tincidunt est purus, ac vestibulum augue maximus in. Suspendisse vel erat et mi ultricies semper. Pellentesque volutpat pellentesque consequat.
diff --git a/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js b/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js
index d043ad38b8b..95c8fb5c78d 100644
--- a/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js
+++ b/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js
@@ -5,7 +5,7 @@ import * as simplePoll from '~/lib/utils/simple_poll';
 
 const commitMessage = 'This is the commit message';
 const commitMessageWithDescription = 'This is the commit message description';
-const createComponent = () => {
+const createComponent = (customConfig = {}) => {
   const Component = Vue.extend(readyToMergeComponent);
   const mr = {
     isPipelineActive: false,
@@ -17,8 +17,12 @@ const createComponent = () => {
     sha: '12345678',
     commitMessage,
     commitMessageWithDescription,
+    shouldRemoveSourceBranch: true,
+    canRemoveSourceBranch: false,
   };
 
+  Object.assign(mr, customConfig.mr);
+
   const service = {
     merge() {},
     poll() {},
@@ -51,7 +55,6 @@ describe('MRWidgetReadyToMerge', () => {
 
   describe('data', () => {
     it('should have default data', () => {
-      expect(vm.removeSourceBranch).toBeTruthy(true);
       expect(vm.mergeWhenBuildSucceeds).toBeFalsy();
       expect(vm.useCommitMessageWithDescription).toBeFalsy();
       expect(vm.setToMergeWhenPipelineSucceeds).toBeFalsy();
@@ -166,6 +169,36 @@ describe('MRWidgetReadyToMerge', () => {
         expect(vm.isMergeButtonDisabled).toBeTruthy();
       });
     });
+
+    describe('Remove source branch checkbox', () => {
+      describe('when user can merge but cannot delete branch', () => {
+        it('isRemoveSourceBranchButtonDisabled should be true', () => {
+          expect(vm.isRemoveSourceBranchButtonDisabled).toBe(true);
+        });
+
+        it('should be disabled in the rendered output', () => {
+          const checkboxElement = vm.$el.getElementById('remove-source-branch-input');
+          expect(checkboxElement.getAttribute('disabled')).toBe('disabled');
+        });
+      });
+
+      describe('when user can merge and can delete branch', () => {
+        beforeEach(() => {
+          this.customVm = createComponent({
+            mr: { canRemoveSourceBranch: true },
+          });
+        });
+
+        it('isRemoveSourceBranchButtonDisabled should be false', () => {
+          expect(this.customVm.isRemoveSourceBranchButtonDisabled).toBe(false);
+        });
+
+        it('should be enabled in rendered output', () => {
+          const checkboxElement = this.customVm.$el.getElementById('remove-source-branch-input');
+          expect(checkboxElement.getAttribute('disabled')).toBeNull();
+        });
+      });
+    });
   });
 
   describe('methods', () => {

From 5aee04dd4ad3fa13e20cba2efc4d267ef210039e Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Mon, 22 May 2017 20:46:38 -0400
Subject: [PATCH 02/14] Shush eslint.

---
 .../vue_merge_request_widget/stores/mr_widget_store.js          | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
index b3a0d9c0b11..350b7a98d2a 100644
--- a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
+++ b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
@@ -53,7 +53,7 @@ export default class MergeRequestStore {
     this.removeWIPPath = data.remove_wip_path;
     this.sourceBranchRemoved = !data.source_branch_exists;
     this.shouldRemoveSourceBranch = mergeParams.should_remove_source_branch ||
-      mergeParams.force_remove_source_branch === "1" || false;
+      mergeParams.force_remove_source_branch === '1' || false;
     this.onlyAllowMergeIfPipelineSucceeds = data.only_allow_merge_if_pipeline_succeeds || false;
     this.mergeWhenPipelineSucceeds = data.merge_when_pipeline_succeeds || false;
     this.mergePath = data.merge_path;

From 095fa89b95c46a7242c473e9448fbdb43c0a402a Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Mon, 22 May 2017 20:49:26 -0400
Subject: [PATCH 03/14] Don't use getElementById in specs.

---
 .../components/states/mr_widget_ready_to_merge_spec.js        | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js b/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js
index 95c8fb5c78d..732b516badd 100644
--- a/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js
+++ b/spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js
@@ -177,7 +177,7 @@ describe('MRWidgetReadyToMerge', () => {
         });
 
         it('should be disabled in the rendered output', () => {
-          const checkboxElement = vm.$el.getElementById('remove-source-branch-input');
+          const checkboxElement = vm.$el.querySelector('#remove-source-branch-input');
           expect(checkboxElement.getAttribute('disabled')).toBe('disabled');
         });
       });
@@ -194,7 +194,7 @@ describe('MRWidgetReadyToMerge', () => {
         });
 
         it('should be enabled in rendered output', () => {
-          const checkboxElement = this.customVm.$el.getElementById('remove-source-branch-input');
+          const checkboxElement = this.customVm.$el.querySelector('#remove-source-branch-input');
           expect(checkboxElement.getAttribute('disabled')).toBeNull();
         });
       });

From 21fe8f3646618455514e9888dae913be1e14b15b Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Mon, 22 May 2017 22:58:37 -0400
Subject: [PATCH 04/14] Shush rubocop.

---
 spec/features/merge_requests/edit_mr_spec.rb | 1 -
 1 file changed, 1 deletion(-)

diff --git a/spec/features/merge_requests/edit_mr_spec.rb b/spec/features/merge_requests/edit_mr_spec.rb
index f4bfe7e19f6..c77a5c68bc6 100644
--- a/spec/features/merge_requests/edit_mr_spec.rb
+++ b/spec/features/merge_requests/edit_mr_spec.rb
@@ -29,7 +29,6 @@ feature 'Edit Merge Request', feature: true do
       expect(page).to have_content 'Someone edited the merge request the same time you did'
     end
 
-
     it 'allows to unselect "Remove source branch"', js: true do
       merge_request.update(merge_params: { 'force_remove_source_branch' => '1' })
       expect(merge_request.merge_params['force_remove_source_branch']).to be_truthy

From ff5044d8e9f856d4398795618103ce6206b9afee Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Tue, 23 May 2017 12:08:50 -0400
Subject: [PATCH 05/14] Update spinach specs to explicitly check Remove Source
 Branch.

---
 features/project/merge_requests/accept.feature      | 3 ++-
 features/steps/project/merge_requests/acceptance.rb | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/features/project/merge_requests/accept.feature b/features/project/merge_requests/accept.feature
index c45ed9ea68b..2ab1c19f452 100644
--- a/features/project/merge_requests/accept.feature
+++ b/features/project/merge_requests/accept.feature
@@ -7,6 +7,7 @@ Feature: Project Merge Requests Acceptance
   @javascript
   Scenario: Accepting the Merge Request and removing the source branch
     Given I am on the Merge Request detail page
+    When I check the "Remove source branch" option
     And I click on Accept Merge Request
     Then I should see merge request merged
     And I should not see the Remove Source Branch button
@@ -14,6 +15,7 @@ Feature: Project Merge Requests Acceptance
   @javascript
   Scenario: Accepting the Merge Request when URL has an anchor
     Given I am on the Merge Request detail with note anchor page
+    When I check the "Remove source branch" option
     And I click on Accept Merge Request
     Then I should see merge request merged
     And I should not see the Remove Source Branch button
@@ -21,7 +23,6 @@ Feature: Project Merge Requests Acceptance
   @javascript
   Scenario: Accepting the Merge Request without removing the source branch
     Given I am on the Merge Request detail page
-    When I click on "Remove source branch" option
     When I click on Accept Merge Request
     Then I should see merge request merged
     And I should see the Remove Source Branch button
diff --git a/features/steps/project/merge_requests/acceptance.rb b/features/steps/project/merge_requests/acceptance.rb
index 3c976f675a2..cdaa849308c 100644
--- a/features/steps/project/merge_requests/acceptance.rb
+++ b/features/steps/project/merge_requests/acceptance.rb
@@ -11,10 +11,14 @@ class Spinach::Features::ProjectMergeRequestsAcceptance < Spinach::FeatureSteps
     visit merge_request_path(@merge_request, anchor: 'note_123')
   end
 
-  step 'I click on "Remove source branch" option' do
+  step 'I uncheck the "Remove source branch" option' do
     uncheck('Remove source branch')
   end
 
+  step 'I check the "Remove source branch" option' do
+    check('Remove source branch')
+  end
+
   step 'I click on Accept Merge Request' do
     click_button('Merge')
   end

From 92d290c97b14e95864a123b29fa28376415a8edf Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Tue, 23 May 2017 12:40:17 -0400
Subject: [PATCH 06/14] Set merge params to force_remove_source_branch by
 default.

---
 .../merge_requests/merge_when_pipeline_succeeds_spec.rb     | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb b/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
index 11b6f0c0a64..dd87af06820 100644
--- a/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
+++ b/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
@@ -7,7 +7,8 @@ feature 'Merge When Pipeline Succeeds', :feature, :js do
   let(:merge_request) do
     create(:merge_request_with_diffs, source_project: project,
                                       author: user,
-                                      title: 'Bug NS-04')
+                                      title: 'Bug NS-04',
+                                      merge_params: { force_remove_source_branch: '1' })
   end
 
   let(:pipeline) do
@@ -82,7 +83,8 @@ feature 'Merge When Pipeline Succeeds', :feature, :js do
                    source_project: project,
                    title: 'Bug NS-04',
                    author: user,
-                   merge_user: user)
+                   merge_user: user,
+                   merge_params: { force_remove_source_branch: '1' })
         end
 
         before do

From 0eaa65d508eca7765e470018ab0d8006d0a8c9f8 Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Tue, 23 May 2017 16:24:49 -0400
Subject: [PATCH 07/14] Add spec for disabled Remove source branch checkbox.

---
 .../merge_requests/created_from_fork_spec.rb      | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/spec/features/merge_requests/created_from_fork_spec.rb b/spec/features/merge_requests/created_from_fork_spec.rb
index bf34c99b92a..a97768b757a 100644
--- a/spec/features/merge_requests/created_from_fork_spec.rb
+++ b/spec/features/merge_requests/created_from_fork_spec.rb
@@ -63,6 +63,21 @@ feature 'Merge request created from fork' do
     end
   end
 
+  context 'user can merge into source project but cannot push to fork' do
+    given(:user2) { create(:user) }
+
+    background do
+      project.team << [user2, :master]
+      logout
+      login_as user2
+      visit_merge_request(merge_request)
+    end
+
+    scenario 'user cannot remove source branch', js: true do
+      expect(page).to have_field('remove-source-branch-input', disabled: true)
+    end
+  end
+
   def visit_merge_request(mr)
     visit namespace_project_merge_request_path(project.namespace,
                                                project, mr)

From 41e0029c9473edf8b3dde7cb564b1c64342f8faa Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Wed, 24 May 2017 16:03:35 -0400
Subject: [PATCH 08/14] Move spec and add one for merge button not disabled.

---
 spec/features/merge_requests/widget_spec.rb | 29 +++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/spec/features/merge_requests/widget_spec.rb b/spec/features/merge_requests/widget_spec.rb
index ae799584c0f..ac10a1a1078 100644
--- a/spec/features/merge_requests/widget_spec.rb
+++ b/spec/features/merge_requests/widget_spec.rb
@@ -206,4 +206,33 @@ describe 'Merge request', :feature, :js do
       end
     end
   end
+
+  context 'user can merge into source project but cannot push to fork', js: true do
+    let(:fork_project) { create(:project, :public) }
+
+    let!(:merge_request_from_fork) do
+      create(:forked_project_link, forked_to_project: fork_project,
+                                   forked_from_project: project)
+
+      create(:merge_request_with_diffs, source_project: fork_project,
+                                        target_project: project)
+    end
+
+    let(:user2) { create(:user) }
+
+    before do
+      project.team << [user2, :master]
+      logout
+      login_as user2
+      visit namespace_project_merge_request_path(project.namespace, project, merge_request_from_fork)
+    end
+
+    it 'user can merge into the source project' do
+      expect(page).to have_button('Merge', disabled: false)
+    end
+
+    it 'user cannot remove source branch' do
+      expect(page).to have_field('remove-source-branch-input', disabled: true)
+    end
+  end
 end

From 7e1e13899ed037de05a7aeaf8179eb8902360442 Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Wed, 24 May 2017 16:07:05 -0400
Subject: [PATCH 09/14] Remove spec from created_from_fork_spec.

---
 .../merge_requests/created_from_fork_spec.rb      | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/spec/features/merge_requests/created_from_fork_spec.rb b/spec/features/merge_requests/created_from_fork_spec.rb
index a97768b757a..bf34c99b92a 100644
--- a/spec/features/merge_requests/created_from_fork_spec.rb
+++ b/spec/features/merge_requests/created_from_fork_spec.rb
@@ -63,21 +63,6 @@ feature 'Merge request created from fork' do
     end
   end
 
-  context 'user can merge into source project but cannot push to fork' do
-    given(:user2) { create(:user) }
-
-    background do
-      project.team << [user2, :master]
-      logout
-      login_as user2
-      visit_merge_request(merge_request)
-    end
-
-    scenario 'user cannot remove source branch', js: true do
-      expect(page).to have_field('remove-source-branch-input', disabled: true)
-    end
-  end
-
   def visit_merge_request(mr)
     visit namespace_project_merge_request_path(project.namespace,
                                                project, mr)

From 9b479f4305c030257a6b179780c911f215c65482 Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Wed, 24 May 2017 17:39:36 -0400
Subject: [PATCH 10/14] Set up merge request from fork more simply.

---
 spec/features/merge_requests/widget_spec.rb | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/spec/features/merge_requests/widget_spec.rb b/spec/features/merge_requests/widget_spec.rb
index ac10a1a1078..016c641b3c5 100644
--- a/spec/features/merge_requests/widget_spec.rb
+++ b/spec/features/merge_requests/widget_spec.rb
@@ -209,22 +209,14 @@ describe 'Merge request', :feature, :js do
 
   context 'user can merge into source project but cannot push to fork', js: true do
     let(:fork_project) { create(:project, :public) }
-
-    let!(:merge_request_from_fork) do
-      create(:forked_project_link, forked_to_project: fork_project,
-                                   forked_from_project: project)
-
-      create(:merge_request_with_diffs, source_project: fork_project,
-                                        target_project: project)
-    end
-
     let(:user2) { create(:user) }
 
     before do
       project.team << [user2, :master]
       logout
       login_as user2
-      visit namespace_project_merge_request_path(project.namespace, project, merge_request_from_fork)
+      merge_request.update(target_project: fork_project)
+      visit namespace_project_merge_request_path(project.namespace, project, merge_request)
     end
 
     it 'user can merge into the source project' do

From 33923a49f85cb814f87a495d63c09503f53466e4 Mon Sep 17 00:00:00 2001
From: Oswaldo Ferreira <oswaldo@gitlab.com>
Date: Wed, 24 May 2017 21:54:57 -0300
Subject: [PATCH 11/14] Expose remove_source_branch boolean/null

---
 app/serializers/merge_request_entity.rb               | 1 +
 spec/fixtures/api/schemas/entities/merge_request.json | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/app/serializers/merge_request_entity.rb b/app/serializers/merge_request_entity.rb
index b3247ae36dd..f7eb75395b5 100644
--- a/app/serializers/merge_request_entity.rb
+++ b/app/serializers/merge_request_entity.rb
@@ -39,6 +39,7 @@ class MergeRequestEntity < IssuableEntity
   expose :commits_count
   expose :cannot_be_merged?, as: :has_conflicts
   expose :can_be_merged?, as: :can_be_merged
+  expose :remove_source_branch?, as: :remove_source_branch
 
   expose :project_archived do |merge_request|
     merge_request.project.archived?
diff --git a/spec/fixtures/api/schemas/entities/merge_request.json b/spec/fixtures/api/schemas/entities/merge_request.json
index 4afbb87453e..b6a59a6cc47 100644
--- a/spec/fixtures/api/schemas/entities/merge_request.json
+++ b/spec/fixtures/api/schemas/entities/merge_request.json
@@ -92,7 +92,8 @@
     "diverged_commits_count": { "type": "integer" },
     "commit_change_content_path": { "type": "string" },
     "remove_wip_path": { "type": "string" },
-    "commits_count": { "type": "integer" }
+    "commits_count": { "type": "integer" },
+    "remove_source_branch": { "type": ["boolean", "null"] }
   },
   "additionalProperties": false
 }

From 8d2a1591fb9ceeebe1d820b8e364f8b7b85f2987 Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Thu, 25 May 2017 12:38:16 -0400
Subject: [PATCH 12/14] Update shouldRemoveSourceBranch against API entity
 changes.

---
 .../vue_merge_request_widget/stores/mr_widget_store.js        | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
index 350b7a98d2a..2b45aabd35d 100644
--- a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
+++ b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
@@ -11,7 +11,6 @@ export default class MergeRequestStore {
   setData(data) {
     const currentUser = data.current_user;
     const pipelineStatus = data.pipeline ? data.pipeline.details.status : null;
-    const mergeParams = data.merge_params || {};
 
     this.title = data.title;
     this.targetBranch = data.target_branch;
@@ -52,8 +51,7 @@ export default class MergeRequestStore {
     this.cancelAutoMergePath = data.cancel_merge_when_pipeline_succeeds_path;
     this.removeWIPPath = data.remove_wip_path;
     this.sourceBranchRemoved = !data.source_branch_exists;
-    this.shouldRemoveSourceBranch = mergeParams.should_remove_source_branch ||
-      mergeParams.force_remove_source_branch === '1' || false;
+    this.shouldRemoveSourceBranch = data.remove_source_branch;
     this.onlyAllowMergeIfPipelineSucceeds = data.only_allow_merge_if_pipeline_succeeds || false;
     this.mergeWhenPipelineSucceeds = data.merge_when_pipeline_succeeds || false;
     this.mergePath = data.merge_path;

From 08a7073eb890f9a885aa6a78caefcec3090644b2 Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Thu, 25 May 2017 12:47:06 -0400
Subject: [PATCH 13/14] Fallback to false when remove_source_branch is null.

---
 .../vue_merge_request_widget/stores/mr_widget_store.js          | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
index 2b45aabd35d..4833fb325af 100644
--- a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
+++ b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
@@ -51,7 +51,7 @@ export default class MergeRequestStore {
     this.cancelAutoMergePath = data.cancel_merge_when_pipeline_succeeds_path;
     this.removeWIPPath = data.remove_wip_path;
     this.sourceBranchRemoved = !data.source_branch_exists;
-    this.shouldRemoveSourceBranch = data.remove_source_branch;
+    this.shouldRemoveSourceBranch = data.remove_source_branch || false;
     this.onlyAllowMergeIfPipelineSucceeds = data.only_allow_merge_if_pipeline_succeeds || false;
     this.mergeWhenPipelineSucceeds = data.merge_when_pipeline_succeeds || false;
     this.mergePath = data.merge_path;

From 099a9e016e8c09609fbbbc96c6bca4781f87d487 Mon Sep 17 00:00:00 2001
From: Bryce Johnson <bryce@gitlab.com>
Date: Thu, 25 May 2017 14:43:53 -0400
Subject: [PATCH 14/14] Update MWPS feature spec per change to remove source
 branch default.

---
 .../merge_requests/merge_when_pipeline_succeeds_spec.rb       | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb b/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
index dd87af06820..e1ba1df18a4 100644
--- a/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
+++ b/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
@@ -42,7 +42,7 @@ feature 'Merge When Pipeline Succeeds', :feature, :js do
           click_button "Merge when pipeline succeeds"
 
           expect(page).to have_content "Set by #{user.name} to be merged automatically when the pipeline succeeds."
-          expect(page).to have_content "The source branch will be removed."
+          expect(page).to have_content "The source branch will not be removed."
           expect(page).to have_selector ".js-cancel-auto-merge"
           visit_merge_request(merge_request) # Needed to refresh the page
           expect(page).to have_content /enabled an automatic merge when the pipeline for \h{8} succeeds/i
@@ -101,7 +101,7 @@ feature 'Merge When Pipeline Succeeds', :feature, :js do
         click_link 'Merge when pipeline succeeds'
 
         expect(page).to have_content "Set by #{user.name} to be merged automatically when the pipeline succeeds."
-        expect(page).to have_content "The source branch will be removed."
+        expect(page).to have_content "The source branch will not be removed."
         expect(page).to have_link "Cancel automatic merge"
       end
     end