Add delete branch modals behind feature flag

Replaces the bootstrap modal for the delete branch button and
confirmation.

Changelog: added

app/assets/javascripts/branches/components/delete_branch_button.vue

+<script>
+import { GlButton, GlTooltipDirective } from '@gitlab/ui';
+import { s__ } from '~/locale';
+import eventHub from '../event_hub';
+
+export default {
+  name: 'DeleteBranchButton',
+  components: { GlButton },
+  directives: {
+    GlTooltip: GlTooltipDirective,
+  },
+  props: {
+    branchName: {
+      type: String,
+      required: false,
+      default: '',
+    },
+    defaultBranchName: {
+      type: String,
+      required: false,
+      default: '',
+    },
+    deletePath: {
+      type: String,
+      required: false,
+      default: '',
+    },
+    tooltip: {
+      type: String,
+      required: false,
+      default: s__('Branches|Delete branch'),
+    },
+    disabled: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+    isProtectedBranch: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+    merged: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+  },
+  computed: {
+    variant() {
+      if (this.disabled) {
+        return 'default';
+      }
+      return 'danger';
+    },
+    title() {
+      if (this.isProtectedBranch && this.disabled) {
+        return s__('Branches|Only a project maintainer or owner can delete a protected branch');
+      } else if (this.isProtectedBranch) {
+        return s__('Branches|Delete protected branch');
+      }
+      return this.tooltip;
+    },
+  },
+  methods: {
+    openModal() {
+      eventHub.$emit('openModal', {
+        branchName: this.branchName,
+        defaultBranchName: this.defaultBranchName,
+        deletePath: this.deletePath,
+        isProtectedBranch: this.isProtectedBranch,
+        merged: this.merged,
+      });
+    },
+  },
+};
+</script>
+
+<template>
+  <gl-button
+    v-gl-tooltip.hover
+    icon="remove"
+    class="js-delete-branch-button"
+    data-qa-selector="delete_branch_button"
+    :disabled="disabled"
+    :variant="variant"
+    :title="title"
+    :aria-label="title"
+    @click="openModal"
+  />
+</template>

app/assets/javascripts/branches/components/delete_branch_modal.vue

+<script>
+import { GlButton, GlFormInput, GlModal, GlSprintf, GlAlert } from '@gitlab/ui';
+import { BV_SHOW_MODAL, BV_HIDE_MODAL } from '~/lib/utils/constants';
+import csrf from '~/lib/utils/csrf';
+import { sprintf, s__ } from '~/locale';
+import eventHub from '../event_hub';
+
+export default {
+  csrf,
+  components: {
+    GlModal,
+    GlButton,
+    GlFormInput,
+    GlSprintf,
+    GlAlert,
+  },
+  data() {
+    return {
+      visible: false,
+      isProtectedBranch: false,
+      branchName: '',
+      defaultBranchName: '',
+      deletePath: '',
+      merged: false,
+      enteredBranchName: '',
+      modalId: 'delete-branch-modal',
+    };
+  },
+  computed: {
+    title() {
+      const modalTitle = this.isProtectedBranch
+        ? this.$options.i18n.modalTitleProtectedBranch
+        : this.$options.i18n.modalTitle;
+
+      return sprintf(modalTitle, { branchName: this.branchName });
+    },
+    message() {
+      const modalMessage = this.isProtectedBranch
+        ? this.$options.i18n.modalMessageProtectedBranch
+        : this.$options.i18n.modalMessage;
+
+      return sprintf(modalMessage, { branchName: this.branchName });
+    },
+    unmergedWarning() {
+      return sprintf(this.$options.i18n.unmergedWarning, {
+        defaultBranchName: this.defaultBranchName,
+      });
+    },
+    undoneWarning() {
+      return sprintf(this.$options.i18n.undoneWarning, {
+        buttonText: this.buttonText,
+      });
+    },
+    confirmationText() {
+      return sprintf(this.$options.i18n.confirmationText, {
+        branchName: this.branchName,
+      });
+    },
+    buttonText() {
+      return this.isProtectedBranch
+        ? this.$options.i18n.deleteButtonTextProtectedBranch
+        : this.$options.i18n.deleteButtonText;
+    },
+    branchNameConfirmed() {
+      return this.enteredBranchName === this.branchName;
+    },
+    deleteButtonDisabled() {
+      return this.isProtectedBranch && !this.branchNameConfirmed;
+    },
+  },
+  mounted() {
+    eventHub.$on('openModal', (options) => {
+      this.openModal(options);
+    });
+  },
+  methods: {
+    openModal({ isProtectedBranch, branchName, defaultBranchName, deletePath, merged }) {
+      this.isProtectedBranch = isProtectedBranch;
+      this.branchName = branchName;
+      this.defaultBranchName = defaultBranchName;
+      this.deletePath = deletePath;
+      this.merged = merged;
+
+      this.$root.$emit(BV_SHOW_MODAL, this.modalId);
+    },
+    submitForm() {
+      this.$refs.form.submit();
+    },
+    closeModal() {
+      this.$root.$emit(BV_HIDE_MODAL, this.modalId);
+    },
+  },
+  i18n: {
+    modalTitle: s__('Branches|Delete branch. Are you ABSOLUTELY SURE?'),
+    modalTitleProtectedBranch: s__('Branches|Delete protected branch. Are you ABSOLUTELY SURE?'),
+    modalMessage: s__(
+      "Branches|You're about to permanently delete the branch %{strongStart}%{branchName}.%{strongEnd}",
+    ),
+    modalMessageProtectedBranch: s__(
+      "Branches|You're about to permanently delete the protected branch %{strongStart}%{branchName}.%{strongEnd}",
+    ),
+    unmergedWarning: s__(
+      'Branches|This branch hasn’t been merged into %{defaultBranchName}. To avoid data loss, consider merging this branch before deleting it.',
+    ),
+    undoneWarning: s__(
+      'Branches|Once you confirm and press %{strongStart}%{buttonText},%{strongEnd} it cannot be undone or recovered.',
+    ),
+    cancelButtonText: s__('Branches|Cancel, keep branch'),
+    confirmationText: s__(
+      'Branches|Deleting the %{strongStart}%{branchName}%{strongEnd} branch cannot be undone. Are you sure?',
+    ),
+    confirmationTextProtectedBranch: s__('Branches|Please type the following to confirm:'),
+    deleteButtonText: s__('Branches|Yes, delete branch'),
+    deleteButtonTextProtectedBranch: s__('Branches|Yes, delete protected branch'),
+  },
+};
+</script>
+
+<template>
+  <gl-modal :visible="visible" size="sm" :modal-id="modalId" :title="title">
+    <gl-alert class="gl-mb-5" variant="danger" :dismissible="false">
+      <div data-testid="modal-message">
+        <gl-sprintf :message="message">
+          <template #strong="{ content }">
+            <strong> {{ content }} </strong>
+          </template>
+        </gl-sprintf>
+        <p v-if="!merged" class="gl-mb-0 gl-mt-4">
+          {{ unmergedWarning }}
+        </p>
+      </div>
+    </gl-alert>
+
+    <form ref="form" :action="deletePath" method="post">
+      <div v-if="isProtectedBranch" class="gl-mt-4">
+        <p>
+          <gl-sprintf :message="undoneWarning">
+            <template #strong="{ content }">
+              <strong> {{ content }} </strong>
+            </template>
+          </gl-sprintf>
+        </p>
+        <p>
+          <gl-sprintf :message="$options.i18n.confirmationTextProtectedBranch">
+            <template #strong="{ content }">
+              {{ content }}
+            </template>
+          </gl-sprintf>
+          <code class="gl-white-space-pre-wrap"> {{ branchName }} </code>
+          <gl-form-input
+            v-model="enteredBranchName"
+            name="delete_branch_input"
+            type="text"
+            class="gl-mt-4"
+            aria-labelledby="input-label"
+            autocomplete="off"
+          />
+        </p>
+      </div>
+      <div v-else>
+        <p class="gl-mt-4">
+          <gl-sprintf :message="confirmationText">
+            <template #strong="{ content }">
+              <strong>
+                {{ content }}
+              </strong>
+            </template>
+          </gl-sprintf>
+        </p>
+      </div>
+
+      <input ref="method" type="hidden" name="_method" value="delete" />
+      <input :value="$options.csrf.token" type="hidden" name="authenticity_token" />
+    </form>
+
+    <template #modal-footer>
+      <div class="gl-display-flex gl-flex-direction-row gl-justify-content-end gl-flex-wrap gl-m-0">
+        <gl-button @click="closeModal">
+          {{ $options.i18n.cancelButtonText }}
+        </gl-button>
+        <div class="gl-mr-3"></div>
+        <gl-button
+          ref="deleteBranchButton"
+          :disabled="deleteButtonDisabled"
+          variant="danger"
+          data-qa-selector="delete_branch_confirmation_button"
+          data-testid="delete_branch_confirmation_button"
+          @click="submitForm"
+          >{{ buttonText }}</gl-button
+        >
+      </div>
+    </template>
+  </gl-modal>
+</template>

app/assets/javascripts/branches/event_hub.js

+import createEventHub from '~/helpers/event_hub_factory';
+
+export default createEventHub();

app/assets/javascripts/branches/init_delete_branch_button.js

+import Vue from 'vue';
+import DeleteBranchButton from '~/branches/components/delete_branch_button.vue';
+import { parseBoolean } from '~/lib/utils/common_utils';
+
+export default function initDeleteBranchButton(el) {
+  if (!el) {
+    return false;
+  }
+
+  const {
+    branchName,
+    defaultBranchName,
+    deletePath,
+    tooltip,
+    disabled,
+    isProtectedBranch,
+    merged,
+  } = el.dataset;
+
+  return new Vue({
+    el,
+    render: (createElement) =>
+      createElement(DeleteBranchButton, {
+        props: {
+          branchName,
+          defaultBranchName,
+          deletePath,
+          tooltip,
+          disabled: parseBoolean(disabled),
+          isProtectedBranch: parseBoolean(isProtectedBranch),
+          merged: parseBoolean(merged),
+        },
+      }),
+  });
+}

app/assets/javascripts/branches/init_delete_branch_modal.js

+import Vue from 'vue';
+import DeleteBranchModal from '~/branches/components/delete_branch_modal.vue';
+
+export default function initDeleteBranchModal() {
+  const el = document.querySelector('.js-delete-branch-modal');
+  if (!el) {
+    return false;
+  }
+
+  return new Vue({
+    el,
+    render(createComponent) {
+      return createComponent(DeleteBranchModal);
+    },
+  });
+}

app/assets/javascripts/pages/projects/branches/index/index.js

@@ -3,6 +3,8 @@ import AjaxLoadingSpinner from '~/branches/ajax_loading_spinner';
 import BranchSortDropdown from '~/branches/branch_sort_dropdown';
 import DeleteModal from '~/branches/branches_delete_modal';
 import initDiverganceGraph from '~/branches/divergence_graph';
+import initDeleteBranchButton from '~/branches/init_delete_branch_button';
+import initDeleteBranchModal from '~/branches/init_delete_branch_modal';
 
 AjaxLoadingSpinner.init();
 new DeleteModal(); // eslint-disable-line no-new
@@ -14,3 +16,9 @@ const { divergingCountsEndpoint, defaultBranch } = document.querySelector(
 initDiverganceGraph(divergingCountsEndpoint, defaultBranch);
 BranchSortDropdown();
 initDeprecatedRemoveRowBehavior();
+
+document
+  .querySelectorAll('.js-delete-branch-button')
+  .forEach((elem) => initDeleteBranchButton(elem));
+
+initDeleteBranchModal();

app/views/projects/branches/_branch.html.haml

@@ -48,7 +48,10 @@
 
     = render 'projects/buttons/download', project: @project, ref: branch.name, pipeline: @refs_pipelines[branch.name], class: 'gl-vertical-align-top'
 
-    - if can?(current_user, :push_code, @project)
+    - if Feature.enabled?(:delete_branch_confirmation_modals, @project, default_enabled: :yaml)
+      = render 'projects/branches/delete_branch_modal_button', project: @project, branch: branch, merged: merged
+
+    - elsif can?(current_user, :push_code, @project)
       - if branch.name == @project.repository.root_ref
         - delete_default_branch_tooltip = s_('Branches|The default branch cannot be deleted')
         %span.gl-display-inline-block.has-tooltip{ title: delete_default_branch_tooltip }

app/views/projects/branches/_delete_branch_modal_button.html.haml

+- if branch.name == @project.repository.root_ref
+  .js-delete-branch-button{ data: { tooltip: s_('Branches|The default branch cannot be deleted'),
+    disabled: true.to_s } }
+- elsif protected_branch?(@project, branch)
+  - if can?(current_user, :push_to_delete_protected_branch, @project)
+    .js-delete-branch-button{ data: { branch_name: branch.name,
+      is_protected_branch: true.to_s,
+      merged: merged.to_s,
+      default_branch_name: @project.repository.root_ref,
+      delete_path: project_branch_path(@project, branch.name) } }
+  - else
+    .js-delete-branch-button{ data: { is_protected_branch: true.to_s,
+      disabled: true.to_s } }
+- else
+  .js-delete-branch-button{ data: { branch_name: branch.name,
+    merged: merged.to_s,
+    default_branch_name: @project.repository.root_ref,
+    delete_path: project_branch_path(@project, branch.name) } }

app/views/projects/branches/index.html.haml

@@ -54,4 +54,7 @@
   .nothing-here-block
     = s_('Branches|No branches to show')
 
-= render 'projects/branches/delete_protected_modal'
+- if Feature.enabled?(:delete_branch_confirmation_modals, @project, default_enabled: :yaml) && can?(current_user, :push_code, @project)
+  .js-delete-branch-modal
+- elsif can?(current_user, :push_code, @project)
+  = render 'projects/branches/delete_protected_modal'

config/feature_flags/development/delete_branch_confirmation_modals.yml

+---
+name: delete_branch_confirmation_modals
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/56782
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/329052
+milestone: '13.12'
+type: development
+group: group::expansion
+default_enabled: false

locale/gitlab.pot

@@ -5378,6 +5378,9 @@ msgstr ""
 msgid "Branches|All"
 msgstr ""
 
+msgid "Branches|Cancel, keep branch"
+msgstr ""
+
 msgid "Branches|Cant find HEAD commit for this branch"
 msgstr ""
 
@@ -5390,6 +5393,9 @@ msgstr ""
 msgid "Branches|Delete branch"
 msgstr ""
 
+msgid "Branches|Delete branch. Are you ABSOLUTELY SURE?"
+msgstr ""
+
 msgid "Branches|Delete merged branches"
 msgstr ""
 
@@ -5399,6 +5405,12 @@ msgstr ""
 msgid "Branches|Delete protected branch '%{branch_name}'?"
 msgstr ""
 
+msgid "Branches|Delete protected branch. Are you ABSOLUTELY SURE?"
+msgstr ""
+
+msgid "Branches|Deleting the %{strongStart}%{branchName}%{strongEnd} branch cannot be undone. Are you sure?"
+msgstr ""
+
 msgid "Branches|Deleting the '%{branch_name}' branch cannot be undone. Are you sure?"
 msgstr ""
 
@@ -5420,12 +5432,18 @@ msgstr ""
 msgid "Branches|Once you confirm and press %{delete_protected_branch}, it cannot be undone or recovered."
 msgstr ""
 
+msgid "Branches|Once you confirm and press %{strongStart}%{buttonText},%{strongEnd} it cannot be undone or recovered."
+msgstr ""
+
 msgid "Branches|Only a project maintainer or owner can delete a protected branch"
 msgstr ""
 
 msgid "Branches|Overview"
 msgstr ""
 
+msgid "Branches|Please type the following to confirm:"
+msgstr ""
+
 msgid "Branches|Protected branches can be managed in %{project_settings_link}."
 msgstr ""
 
@@ -5459,6 +5477,9 @@ msgstr ""
 msgid "Branches|The default branch cannot be deleted"
 msgstr ""
 
+msgid "Branches|This branch hasn’t been merged into %{defaultBranchName}. To avoid data loss, consider merging this branch before deleting it."
+msgstr ""
+
 msgid "Branches|This branch hasn’t been merged into %{default_branch}."
 msgstr ""
 
@@ -5471,6 +5492,18 @@ msgstr ""
 msgid "Branches|To discard the local changes and overwrite the branch with the upstream version, delete it here and choose 'Update Now' above."
 msgstr ""
 
+msgid "Branches|Yes, delete branch"
+msgstr ""
+
+msgid "Branches|Yes, delete protected branch"
+msgstr ""
+
+msgid "Branches|You're about to permanently delete the branch %{strongStart}%{branchName}.%{strongEnd}"
+msgstr ""
+
+msgid "Branches|You're about to permanently delete the protected branch %{strongStart}%{branchName}.%{strongEnd}"
+msgstr ""
+
 msgid "Branches|You’re about to permanently delete the protected branch %{branch_name}."
 msgstr ""
 

qa/qa/page/project/branches/show.rb

@@ -5,13 +5,23 @@ module QA
     module Project
       module Branches
         class Show < Page::Base
+          view 'app/assets/javascripts/branches/components/delete_branch_button.vue' do
+            element :delete_branch_button
+          end
+
+          view 'app/assets/javascripts/branches/components/delete_branch_modal.vue' do
+            element :delete_branch_confirmation_button
+          end
+
           view 'app/views/projects/branches/_branch.html.haml' do
             element :remove_btn
             element :branch_name
           end
+
           view 'app/views/projects/branches/_panel.html.haml' do
             element :all_branches
           end
+
           view 'app/views/projects/branches/index.html.haml' do
             element :delete_merged_branches
           end
@@ -19,12 +29,12 @@ module QA
           def delete_branch(branch_name)
             within_element(:all_branches) do
               within(".js-branch-#{branch_name}") do
-                accept_alert do
-                  click_element(:remove_btn)
-                end
+                click_element(:delete_branch_button)
               end
             end
 
+            click_element(:delete_branch_confirmation_button)
+
             finished_loading?
           end
 

qa/qa/specs/features/browser_ui/3_create/repository/add_list_delete_branches_spec.rb

@@ -2,7 +2,7 @@
 
 module QA
   RSpec.describe 'Create' do
-    describe 'Create, list, and delete branches via web' do
+    describe 'Create, list, and delete branches via web', :requires_admin do
       master_branch = nil
       second_branch = 'second-branch'
       third_branch = 'third-branch'
@@ -24,6 +24,8 @@ module QA
           proj.initialize_with_readme = true
         end
 
+        Runtime::Feature.enable(:delete_branch_confirmation_modals, project: project)
+
         master_branch = project.default_branch
 
         Git::Repository.perform do |repository|

spec/features/projects/branches/user_deletes_branch_spec.rb

@@ -12,7 +12,7 @@ RSpec.describe "User deletes branch", :js do
     sign_in(user)
   end
 
-  it "deletes branch" do
+  it "deletes branch", :js do
     visit(project_branches_path(project))
 
     branch_search = find('input[data-testid="branch-search"]')
@@ -21,11 +21,38 @@ RSpec.describe "User deletes branch", :js do
     branch_search.native.send_keys(:enter)
 
     page.within(".js-branch-improve\\/awesome") do
-      accept_alert { click_link(title: 'Delete branch') }
+      find('.js-delete-branch-button').click
+    end
+
+    page.within '.modal-footer' do
+      click_button 'Yes, delete branch'
     end
 
     wait_for_requests
 
-    expect(page).to have_css(".js-branch-improve\\/awesome", visible: :hidden)
+    expect(page).to have_content('Branch was deleted')
+  end
+
+  context 'when the feature flag :delete_branch_confirmation_modals is disabled' do
+    before do
+      stub_feature_flags(delete_branch_confirmation_modals: false)
+    end
+
+    it "deletes branch" do
+      visit(project_branches_path(project))
+
+      branch_search = find('input[data-testid="branch-search"]')
+
+      branch_search.set('improve/awesome')
+      branch_search.native.send_keys(:enter)
+
+      page.within(".js-branch-improve\\/awesome") do
+        accept_alert { click_link(title: 'Delete branch') }
+      end
+
+      wait_for_requests
+
+      expect(page).to have_css(".js-branch-improve\\/awesome", visible: :hidden)
+    end
   end
 end

spec/features/projects/branches/user_views_branches_spec.rb

@@ -2,7 +2,7 @@
 
 require "spec_helper"
 
-RSpec.describe "User views branches" do
+RSpec.describe "User views branches", :js do
   let_it_be(:project) { create(:project, :repository) }
   let_it_be(:user) { project.owner }
 
@@ -10,9 +10,12 @@ RSpec.describe "User views branches" do
     sign_in(user)
   end
 
-  context "all branches" do
+  context "all branches", :js do
     before do
       visit(project_branches_path(project))
+      branch_search = find('input[data-testid="branch-search"]')
+      branch_search.set('master')
+      branch_search.native.send_keys(:enter)
     end
 
     it "shows branches" do
@@ -20,6 +23,10 @@ RSpec.describe "User views branches" do
 
       expect(page.all(".graph-side")).to all( have_content(/\d+/) )
     end
+
+    it "displays a disabled button with a tooltip for the default branch that cannot be deleted", :js do
+      expect(page).to have_button('The default branch cannot be deleted', disabled: true)
+    end
   end
 
   context "protected branches" do

spec/features/projects/branches_spec.rb

@@ -88,10 +88,7 @@ RSpec.describe 'Branches' do
       it 'shows filtered branches', :js do
         visit project_branches_path(project)
 
-        branch_search = find('input[data-testid="branch-search"]')
-
-        branch_search.set('fix')
-        branch_search.native.send_keys(:enter)
+        search_for_branch('fix')
 
         expect(page).to have_content('fix')
         expect(find('.all-branches')).to have_selector('li', count: 1)
@@ -103,11 +100,10 @@ RSpec.describe 'Branches' do
         visit project_branches_filtered_path(project, state: 'all')
 
         expect(all('.all-branches').last).to have_selector('li', count: 20)
-        accept_confirm do
-          within('.js-branch-item', match: :first) { click_link(title: 'Delete branch') }
-        end
 
-        expect(all('.all-branches').last).to have_selector('li', count: 19)
+        delete_branch_and_confirm
+
+        expect(page).to have_content('Branch was deleted')
       end
     end
 
@@ -153,10 +149,7 @@ RSpec.describe 'Branches' do
       it 'shows filtered branches', :js do
         visit project_branches_filtered_path(project, state: 'all')
 
-        branch_search = find('input[data-testid="branch-search"]')
-
-        branch_search.set('fix')
-        branch_search.native.send_keys(:enter)
+        search_for_branch('fix')
 
         expect(page).to have_content('fix')
         expect(find('.all-branches')).to have_selector('li', count: 1)
@@ -167,19 +160,39 @@ RSpec.describe 'Branches' do
       it 'removes branch after confirmation', :js do
         visit project_branches_filtered_path(project, state: 'all')
 
-        branch_search = find('input[data-testid="branch-search"]')
+        search_for_branch('fix')
 
-        branch_search.set('fix')
-        branch_search.native.send_keys(:enter)
+        expect(all('.all-branches').last).to have_selector('li', count: 1)
 
-        expect(page).to have_content('fix')
-        expect(find('.all-branches')).to have_selector('li', count: 1)
-        accept_confirm do
-          within('.js-branch-fix') { click_link(title: 'Delete branch') }
-        end
+        delete_branch_and_confirm
+
+        expect(page).to have_content('Branch was deleted')
+
+        page.refresh
+
+        search_for_branch('fix')
 
         expect(page).not_to have_content('fix')
-        expect(find('.all-branches')).to have_selector('li', count: 0)
+        expect(all('.all-branches').last).to have_selector('li', count: 0)
+      end
+
+      context 'when the delete_branch_confirmation_modals feature flag is disabled' do
+        it 'removes branch after confirmation', :js do
+          stub_feature_flags(delete_branch_confirmation_modals: false)
+
+          visit project_branches_filtered_path(project, state: 'all')
+
+          search_for_branch('fix')
+
+          expect(page).to have_content('fix')
+          expect(find('.all-branches')).to have_selector('li', count: 1)
+          accept_confirm do
+            within('.js-branch-item', match: :first) { click_link(title: 'Delete branch') }
+          end
+
+          expect(page).not_to have_content('fix')
+          expect(find('.all-branches')).to have_selector('li', count: 0)
+        end
       end
     end
 
@@ -327,4 +340,18 @@ RSpec.describe 'Branches' do
   def create_file(message: 'message', branch_name:)
     repository.create_file(user, generate(:branch), 'content', message: message, branch_name: branch_name)
   end
+
+  def search_for_branch(name)
+    branch_search = find('input[data-testid="branch-search"]')
+    branch_search.set(name)
+    branch_search.native.send_keys(:enter)
+  end
+
+  def delete_branch_and_confirm
+    find('.js-delete-branch-button', match: :first).click
+
+    within '.modal-footer' do
+      click_button 'Yes, delete branch'
+    end
+  end
 end

spec/features/projects/environments/environment_spec.rb

@@ -329,11 +329,11 @@ RSpec.describe 'Environment' do
       expect(page).to have_button('Stop')
     end
 
-    it 'user deletes the branch with running environment' do
+    it 'user deletes the branch with running environment', :js do
       visit project_branches_filtered_path(project, state: 'all', search: 'feature')
 
       remove_branch_with_hooks(project, user, 'feature') do
-        within('.js-branch-feature') { click_link(title: 'Delete branch') }
+        page.within('.js-branch-feature') { find('.js-delete-branch-button').click }
       end
 
       visit_environment(environment)
@@ -341,6 +341,24 @@ RSpec.describe 'Environment' do
       expect(page).not_to have_button('Stop')
     end
 
+    context 'when the feature flag :delete_branch_confirmation_modals is disabled' do
+      before do
+        stub_feature_flags(delete_branch_confirmation_modals: false)
+      end
+
+      it 'user deletes the branch with running environment' do
+        visit project_branches_filtered_path(project, state: 'all', search: 'feature')
+
+        remove_branch_with_hooks(project, user, 'feature') do
+          within('.js-branch-feature') { click_link(title: 'Delete branch') }
+        end
+
+        visit_environment(environment)
+
+        expect(page).not_to have_button('Stop')
+      end
+    end
+
     ##
     # This is a workaround for problem described in #24543
     #

spec/features/protected_branches_spec.rb

@@ -27,7 +27,22 @@ RSpec.describe 'Protected Branches', :js do
         find('input[data-testid="branch-search"]').set('fix')
         find('input[data-testid="branch-search"]').native.send_keys(:enter)
 
-        expect(page).to have_selector('button[data-testid="remove-protected-branch"][disabled]')
+        expect(page).to have_button('Only a project maintainer or owner can delete a protected branch', disabled: true)
+      end
+
+      context 'when feature flag :delete_branch_confirmation_modals is disabled' do
+        before do
+          stub_feature_flags(delete_branch_confirmation_modals: false)
+        end
+
+        it 'does not allow developer to remove protected branch' do
+          visit project_branches_path(project)
+
+          find('input[data-testid="branch-search"]').set('fix')
+          find('input[data-testid="branch-search"]').native.send_keys(:enter)
+
+          expect(page).to have_selector('button[data-testid="remove-protected-branch"][disabled]')
+        end
       end
     end
   end
@@ -52,17 +67,44 @@ RSpec.describe 'Protected Branches', :js do
 
         expect(page).to have_content('fix')
         expect(find('.all-branches')).to have_selector('li', count: 1)
-        page.find('[data-target="#modal-delete-branch"]').click
 
-        expect(page).to have_css('.js-delete-branch[disabled]')
+        expect(page).to have_button('Delete protected branch', disabled: false)
+
+        page.find('.js-delete-branch-button').click
         fill_in 'delete_branch_input', with: 'fix'
-        click_link 'Delete protected branch'
+        click_button 'Yes, delete protected branch'
 
         find('input[data-testid="branch-search"]').set('fix')
         find('input[data-testid="branch-search"]').native.send_keys(:enter)
 
         expect(page).to have_content('No branches to show')
       end
+
+      context 'when the feature flag :delete_branch_confirmation_modals is disabled' do
+        before do
+          stub_feature_flags(delete_branch_confirmation_modals: false)
+        end
+
+        it 'removes branch after modal confirmation' do
+          visit project_branches_path(project)
+
+          find('input[data-testid="branch-search"]').set('fix')
+          find('input[data-testid="branch-search"]').native.send_keys(:enter)
+
+          expect(page).to have_content('fix')
+          expect(find('.all-branches')).to have_selector('li', count: 1)
+          page.find('[data-target="#modal-delete-branch"]').click
+
+          expect(page).to have_css('.js-delete-branch[disabled]')
+          fill_in 'delete_branch_input', with: 'fix'
+          click_link 'Delete protected branch'
+
+          find('input[data-testid="branch-search"]').set('fix')
+          find('input[data-testid="branch-search"]').native.send_keys(:enter)
+
+          expect(page).to have_content('No branches to show')
+        end
+      end
     end
   end
 

spec/frontend/branches/components/__snapshots__/delete_branch_modal_spec.js.snap

+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Delete branch modal Deleting a protected branch (for owner or maintainer) renders the modal correctly 1`] = `
+"<div visible=\\"visible\\">
+  <gl-alert-stub title=\\"\\" dismisslabel=\\"Dismiss\\" variant=\\"danger\\" primarybuttonlink=\\"\\" primarybuttontext=\\"\\" secondarybuttonlink=\\"\\" secondarybuttontext=\\"\\" class=\\"gl-mb-5\\">
+    <div data-testid=\\"modal-message\\">
+      <gl-sprintf-stub message=\\"You're about to permanently delete the protected branch %{strongStart}test_modal.%{strongEnd}\\"></gl-sprintf-stub>
+      <p class=\\"gl-mb-0 gl-mt-4\\">
+        This branch hasn’t been merged into default. To avoid data loss, consider merging this branch before deleting it.
+      </p>
+    </div>
+  </gl-alert-stub>
+  <form action=\\"/path/to/branch\\" method=\\"post\\">
+    <div class=\\"gl-mt-4\\">
+      <p>
+        <gl-sprintf-stub message=\\"Once you confirm and press %{strongStart}Yes, delete protected branch,%{strongEnd} it cannot be undone or recovered.\\"></gl-sprintf-stub>
+      </p>
+      <p>
+        <gl-sprintf-stub message=\\"Please type the following to confirm:\\"></gl-sprintf-stub> <code class=\\"gl-white-space-pre-wrap\\"> test_modal </code>
+        <b-form-input-stub name=\\"delete_branch_input\\" value=\\"\\" autocomplete=\\"off\\" debounce=\\"0\\" type=\\"text\\" aria-labelledby=\\"input-label\\" class=\\"gl-form-input gl-mt-4\\"></b-form-input-stub>
+      </p>
+    </div> <input type=\\"hidden\\" name=\\"_method\\" value=\\"delete\\"> <input type=\\"hidden\\" name=\\"authenticity_token\\">
+  </form>
+  <div class=\\"gl-display-flex gl-flex-direction-row gl-justify-content-end gl-flex-wrap gl-m-0\\">
+    <b-button-stub size=\\"md\\" variant=\\"default\\" type=\\"button\\" tag=\\"button\\" class=\\"gl-button\\">
+      <!---->
+      <!----> <span class=\\"gl-button-text\\">
+        Cancel, keep branch
+      </span></b-button-stub>
+    <div class=\\"gl-mr-3\\"></div>
+    <b-button-stub disabled=\\"true\\" size=\\"md\\" variant=\\"danger\\" type=\\"button\\" tag=\\"button\\" data-qa-selector=\\"delete_branch_confirmation_button\\" data-testid=\\"delete_branch_confirmation_button\\" class=\\"gl-button\\">
+      <!---->
+      <!----> <span class=\\"gl-button-text\\">Yes, delete protected branch</span></b-button-stub>
+  </div>
+</div>"
+`;
+
+exports[`Delete branch modal Deleting a regular branch renders the modal correctly 1`] = `
+"<div visible=\\"visible\\">
+  <gl-alert-stub title=\\"\\" dismisslabel=\\"Dismiss\\" variant=\\"danger\\" primarybuttonlink=\\"\\" primarybuttontext=\\"\\" secondarybuttonlink=\\"\\" secondarybuttontext=\\"\\" class=\\"gl-mb-5\\">
+    <div data-testid=\\"modal-message\\">
+      <gl-sprintf-stub message=\\"You're about to permanently delete the branch %{strongStart}test_modal.%{strongEnd}\\"></gl-sprintf-stub>
+      <p class=\\"gl-mb-0 gl-mt-4\\">
+        This branch hasn’t been merged into default. To avoid data loss, consider merging this branch before deleting it.
+      </p>
+    </div>
+  </gl-alert-stub>
+  <form action=\\"/path/to/branch\\" method=\\"post\\">
+    <div>
+      <p class=\\"gl-mt-4\\">
+        <gl-sprintf-stub message=\\"Deleting the %{strongStart}test_modal%{strongEnd} branch cannot be undone. Are you sure?\\"></gl-sprintf-stub>
+      </p>
+    </div> <input type=\\"hidden\\" name=\\"_method\\" value=\\"delete\\"> <input type=\\"hidden\\" name=\\"authenticity_token\\">
+  </form>
+  <div class=\\"gl-display-flex gl-flex-direction-row gl-justify-content-end gl-flex-wrap gl-m-0\\">
+    <b-button-stub size=\\"md\\" variant=\\"default\\" type=\\"button\\" tag=\\"button\\" class=\\"gl-button\\">
+      <!---->
+      <!----> <span class=\\"gl-button-text\\">
+        Cancel, keep branch
+      </span></b-button-stub>
+    <div class=\\"gl-mr-3\\"></div>
+    <b-button-stub size=\\"md\\" variant=\\"danger\\" type=\\"button\\" tag=\\"button\\" data-qa-selector=\\"delete_branch_confirmation_button\\" data-testid=\\"delete_branch_confirmation_button\\" class=\\"gl-button\\">
+      <!---->
+      <!----> <span class=\\"gl-button-text\\">Yes, delete branch</span></b-button-stub>
+  </div>
+</div>"
+`;

spec/frontend/branches/components/delete_branch_button_spec.js

+import { GlButton } from '@gitlab/ui';
+import { shallowMount } from '@vue/test-utils';
+import DeleteBranchButton from '~/branches/components/delete_branch_button.vue';
+import eventHub from '~/branches/event_hub';
+
+let wrapper;
+let findDeleteButton;
+
+const createComponent = (props = {}) => {
+  wrapper = shallowMount(DeleteBranchButton, {
+    propsData: {
+      branchName: 'test',
+      deletePath: '/path/to/branch',
+      defaultBranchName: 'main',
+      ...props,
+    },
+  });
+};
+
+describe('Delete branch button', () => {
+  let eventHubSpy;
+
+  beforeEach(() => {
+    findDeleteButton = () => wrapper.findComponent(GlButton);
+    eventHubSpy = jest.spyOn(eventHub, '$emit');
+  });
+
+  afterEach(() => {
+    wrapper.destroy();
+  });
+
+  it('renders the button with correct tooltip, style, and icon', () => {
+    createComponent();
+
+    expect(findDeleteButton().attributes()).toMatchObject({
+      title: 'Delete branch',
+      variant: 'danger',
+      icon: 'remove',
+    });
+  });
+
+  it('renders a different tooltip for a protected branch', () => {
+    createComponent({ isProtectedBranch: true });
+
+    expect(findDeleteButton().attributes('title')).toBe('Delete protected branch');
+  });
+
+  it('emits the data to eventHub when button is clicked', () => {
+    createComponent({ merged: true });
+
+    findDeleteButton().vm.$emit('click');
+
+    expect(eventHubSpy).toHaveBeenCalledWith('openModal', {
+      branchName: 'test',
+      defaultBranchName: 'main',
+      deletePath: '/path/to/branch',
+      isProtectedBranch: false,
+      merged: true,
+    });
+  });
+
+  describe('#disabled', () => {
+    it('does not disable the button by default when mounted', () => {
+      createComponent();
+
+      expect(findDeleteButton().attributes('disabled')).not.toBe('true');
+    });
+
+    // Used for unallowed users and for the default branch.
+    it('disables the button when mounted for a disabled modal', () => {
+      createComponent({ disabled: true });
+
+      expect(findDeleteButton().attributes('disabled')).toBe('true');
+    });
+  });
+});

spec/frontend/branches/components/delete_branch_modal_spec.js

+import { GlButton, GlModal, GlFormInput } from '@gitlab/ui';
+import { shallowMount } from '@vue/test-utils';
+import { stubComponent } from 'helpers/stub_component';
+import DeleteBranchModal from '~/branches/components/delete_branch_modal.vue';
+
+let wrapper;
+
+const branchName = 'test_modal';
+
+const createComponent = (data = {}) => {
+  wrapper = shallowMount(DeleteBranchModal, {
+    data() {
+      return {
+        branchName,
+        deletePath: '/path/to/branch',
+        defaultBranchName: 'default',
+        ...data,
+      };
+    },
+    attrs: {
+      visible: true,
+    },
+    stubs: {
+      GlModal: stubComponent(GlModal, {
+        template:
+          '<div><slot name="modal-title"></slot><slot></slot><slot name="modal-footer"></slot></div>',
+      }),
+      GlButton,
+      GlFormInput,
+    },
+  });
+};
+
+const findDeleteButton = () => wrapper.find('[data-testid="delete_branch_confirmation_button"]');
+const findFormInput = () => wrapper.findComponent(GlFormInput);
+
+describe('Delete branch modal', () => {
+  afterEach(() => {
+    wrapper.destroy();
+  });
+
+  describe('Deleting a regular branch', () => {
+    beforeEach(() => {
+      createComponent();
+    });
+
+    it('renders the modal correctly', () => {
+      expect(wrapper.html()).toMatchSnapshot();
+    });
+
+    it('submits the form when clicked', () => {
+      const submitFormSpy = jest.spyOn(wrapper.vm.$refs.form, 'submit');
+
+      return wrapper.vm.$nextTick().then(() => {
+        findDeleteButton().trigger('click');
+
+        expect(submitFormSpy).toHaveBeenCalled();
+      });
+    });
+  });
+
+  describe('Deleting a protected branch (for owner or maintainer)', () => {
+    beforeEach(() => {
+      createComponent({ isProtectedBranch: true });
+    });
+
+    it('renders the modal correctly', () => {
+      expect(wrapper.html()).toMatchSnapshot();
+    });
+
+    it('disables the delete button when branch name input is unconfirmed', () => {
+      expect(findDeleteButton().attributes('disabled')).toBe('true');
+    });
+
+    it('enables the delete button when branch name input is confirmed', () => {
+      return wrapper.vm
+        .$nextTick()
+        .then(() => {
+          findFormInput().vm.$emit('input', branchName);
+        })
+        .then(() => {
+          expect(findDeleteButton()).not.toBeDisabled();
+        });
+    });
+  });
+});