Move diff overflow warning into component

Relocates the diff overflow warning partial into a new component.

Changelog: changed

app/components/diffs/overflow_warning_component.html.haml

+= render Pajamas::AlertComponent.new(title: _('Too many changes to show.'),
+  variant: :warning,
+  alert_class: 'gl-mb-5') do
+  .gl-alert-body
+    = message
+
+  .gl-alert-actions
+    = diff_link
+    = patch_link

app/components/diffs/overflow_warning_component.rb

+# frozen_string_literal: true
+
+module Diffs
+  class OverflowWarningComponent < BaseComponent
+    # Skipping coverage because of https://gitlab.com/gitlab-org/gitlab/-/issues/357381
+    #
+    # This is fully tested by the output in the view part of this component,
+    # but undercoverage doesn't understand the relationship between the two parts.
+    #
+    # :nocov:
+    def initialize(diffs:, diff_files:, project:, commit: nil, merge_request: nil)
+      @diffs = diffs
+      @diff_files = diff_files
+      @project = project
+      @commit = commit
+      @merge_request = merge_request
+    end
+
+    def message
+      html_escape(message_text) % {
+        display_size: @diff_files.size,
+        real_size: @diffs.real_size,
+        strong_open: '<strong>'.html_safe,
+        strong_close: '</strong>'.html_safe
+      }
+    end
+
+    def diff_link
+      text = _("Plain diff")
+
+      if commit?
+        link_to text, project_commit_path(@project, @commit, format: :diff), class: button_classes
+      elsif merge_request?
+        link_to text, merge_request_path(@merge_request, format: :diff), class: button_classes
+      end
+    end
+
+    def patch_link
+      text = _("Email patch")
+
+      if commit?
+        link_to text, project_commit_path(@project, @commit, format: :patch), class: button_classes
+      elsif merge_request?
+        link_to text, merge_request_path(@merge_request, format: :patch), class: button_classes
+      end
+    end
+
+    private
+
+    def commit?
+      current_controller?(:commit) &&
+        @commit.present?
+    end
+
+    def merge_request?
+      current_controller?("projects/merge_requests/diffs") &&
+        @merge_request.present? &&
+        @merge_request.persisted?
+    end
+
+    def message_text
+      _(
+        "To preserve performance only %{strong_open}%{display_size} " \
+        "of %{real_size}%{strong_close} files are displayed."
+      )
+    end
+
+    def button_classes
+      "btn gl-alert-action btn-default gl-button btn-default-secondary"
+    end
+    # :nocov:
+  end
+end

app/views/projects/diffs/_diffs.html.haml

@@ -28,7 +28,7 @@
     = render Diffs::StatsComponent.new(diff_files: diff_files)
 
 - if render_overflow_warning?(diffs)
-  = render 'projects/diffs/warning', diff_files: diffs
+  = render Diffs::OverflowWarningComponent.new(diffs: diffs, diff_files: diff_files, project: @project, commit: @commit, merge_request: @merge_request)
 
 .files{ data: { can_create_note: can_create_note } }
   - if load_diff_files_async

app/views/projects/diffs/_warning.html.haml

-= render Pajamas::AlertComponent.new(title: _('Too many changes to show.'),
-  variant: :warning,
-  alert_class: 'gl-mb-5') do
-  .gl-alert-body
-    = html_escape(_("To preserve performance only %{strong_open}%{display_size} of %{real_size}%{strong_close} files are displayed.")) % { display_size: diff_files.size, real_size: diff_files.real_size, strong_open: '<strong>'.html_safe, strong_close: '</strong>'.html_safe }
-  .gl-alert-actions
-    - if current_controller?(:commit)
-      = link_to _("Plain diff"), project_commit_path(@project, @commit, format: :diff), class: "btn gl-alert-action btn-default gl-button btn-default-secondary"
-      = link_to _("Email patch"), project_commit_path(@project, @commit, format: :patch), class: "btn gl-alert-action btn-default gl-button btn-default-secondary"
-    - elsif current_controller?('projects/merge_requests/diffs') && @merge_request&.persisted?
-      = link_to _("Plain diff"), merge_request_path(@merge_request, format: :diff), class: "btn gl-alert-action btn-default gl-button btn-default-secondary"
-      = link_to _("Email patch"), merge_request_path(@merge_request, format: :patch), class: "btn gl-alert-action btn-default gl-button btn-default-secondary"

spec/components/diffs/overflow_warning_component_spec.rb

+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Diffs::OverflowWarningComponent, type: :component do
+  include RepoHelpers
+
+  subject(:component) do
+    described_class.new(
+      diffs: diffs,
+      diff_files: diff_files,
+      project: project,
+      commit: commit,
+      merge_request: merge_request
+    )
+  end
+
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:repository) { project.repository }
+  let_it_be(:commit) { project.commit(sample_commit.id) }
+  let_it_be(:diffs) { commit.raw_diffs }
+  let_it_be(:diff) { diffs.first }
+  let_it_be(:diff_refs) { commit.diff_refs }
+  let_it_be(:diff_file) { Gitlab::Diff::File.new(diff, diff_refs: diff_refs, repository: repository) }
+  let_it_be(:diff_files) { [diff_file] }
+  let_it_be(:merge_request) { create(:merge_request, source_project: project) }
+
+  let(:expected_button_classes) do
+    "btn gl-alert-action btn-default gl-button btn-default-secondary"
+  end
+
+  describe "rendered component" do
+    subject { rendered_component }
+
+    context "on a commit page" do
+      before do
+        with_controller_class Projects::CommitController do
+          render_inline component
+        end
+      end
+
+      it { is_expected.to include(component.message) }
+
+      it "links to the diff" do
+        expect(component.diff_link).to eq(
+          ActionController::Base.helpers.link_to(
+            _("Plain diff"),
+            project_commit_path(project, commit, format: :diff),
+            class: expected_button_classes
+          )
+        )
+
+        is_expected.to include(component.diff_link)
+      end
+
+      it "links to the patch" do
+        expect(component.patch_link).to eq(
+          ActionController::Base.helpers.link_to(
+            _("Email patch"),
+            project_commit_path(project, commit, format: :patch),
+            class: expected_button_classes
+          )
+        )
+
+        is_expected.to include(component.patch_link)
+      end
+    end
+
+    context "on a merge request page and the merge request is persisted" do
+      before do
+        with_controller_class Projects::MergeRequests::DiffsController do
+          render_inline component
+        end
+      end
+
+      it { is_expected.to include(component.message) }
+
+      it "links to the diff" do
+        expect(component.diff_link).to eq(
+          ActionController::Base.helpers.link_to(
+            _("Plain diff"),
+            merge_request_path(merge_request, format: :diff),
+            class: expected_button_classes
+          )
+        )
+
+        is_expected.to include(component.diff_link)
+      end
+
+      it "links to the patch" do
+        expect(component.patch_link).to eq(
+          ActionController::Base.helpers.link_to(
+            _("Email patch"),
+            merge_request_path(merge_request, format: :patch),
+            class: expected_button_classes
+          )
+        )
+
+        is_expected.to include(component.patch_link)
+      end
+    end
+
+    context "both conditions fail" do
+      before do
+        allow(component).to receive(:commit?).and_return(false)
+        allow(component).to receive(:merge_request?).and_return(false)
+        render_inline component
+      end
+
+      it { is_expected.to include(component.message) }
+      it { is_expected.not_to include(expected_button_classes) }
+      it { is_expected.not_to include("Plain diff") }
+      it { is_expected.not_to include("Email patch") }
+    end
+  end
+
+  describe "#message" do
+    subject { component.message }
+
+    it { is_expected.to be_a(String) }
+
+    it "is HTML-safe" do
+      expect(subject.html_safe?).to be_truthy
+    end
+  end
+
+  describe "#diff_link" do
+    subject { component.diff_link }
+
+    before do
+      allow(component).to receive(:link_to).and_return("foo")
+      render_inline component
+    end
+
+    it "is a string when on a commit page" do
+      allow(component).to receive(:commit?).and_return(true)
+
+      is_expected.to eq("foo")
+    end
+
+    it "is a string when on a merge request page" do
+      allow(component).to receive(:commit?).and_return(false)
+      allow(component).to receive(:merge_request?).and_return(true)
+
+      is_expected.to eq("foo")
+    end
+
+    it "is nil in other situations" do
+      allow(component).to receive(:commit?).and_return(false)
+      allow(component).to receive(:merge_request?).and_return(false)
+
+      is_expected.to be_nil
+    end
+  end
+
+  describe "#patch_link" do
+    subject { component.patch_link }
+
+    before do
+      allow(component).to receive(:link_to).and_return("foo")
+      render_inline component
+    end
+
+    it "is a string when on a commit page" do
+      allow(component).to receive(:commit?).and_return(true)
+
+      is_expected.to eq("foo")
+    end
+
+    it "is a string when on a merge request page" do
+      allow(component).to receive(:commit?).and_return(false)
+      allow(component).to receive(:merge_request?).and_return(true)
+
+      is_expected.to eq("foo")
+    end
+
+    it "is nil in other situations" do
+      allow(component).to receive(:commit?).and_return(false)
+      allow(component).to receive(:merge_request?).and_return(false)
+
+      is_expected.to be_nil
+    end
+  end
+end

spec/spec_helper.rb

@@ -191,6 +191,7 @@ RSpec.configure do |config|
   config.include MigrationsHelpers, :migration
   config.include RedisHelpers
   config.include Rails.application.routes.url_helpers, type: :routing
+  config.include Rails.application.routes.url_helpers, type: :component
   config.include PolicyHelpers, type: :policy
   config.include ExpectRequestWithStatus, type: :request
   config.include IdempotentWorkerHelper, type: :worker