feat(get_prs_between_tags): add opt-in fail_on_error (#772)

Author: dcalhoun

CHANGELOG.md

@@ -10,7 +10,7 @@ _None_
 
 ### New Features
 
-_None_
+- `get_prs_between_tags` now accepts a `fail_on_error:` parameter. [#772]
 
 ### Bug Fixes
 

lib/fastlane/plugin/wpmreleasetoolkit/actions/common/get_prs_between_tags.rb

@@ -25,6 +25,8 @@ def self.run(params)
             config_file_path: config_file_path
           )
         rescue StandardError => e
+          raise if params[:fail_on_error]
+
           error_msg = "❌ Error computing the list of PRs since #{previous_tag || 'last release'}: `#{e.message}`"
           UI.important(error_msg)
           error_msg # Use error message as GitHub Release body to help us be aware of what went wrong.
@@ -102,6 +104,15 @@ def self.available_options
                                                     'See https://docs.github.com/en/repositories/releasing-projects-on-github/automatically-generated-release-notes#configuration-options',
                                        optional: true,
                                        type: String),
+          FastlaneCore::ConfigItem.new(key: :fail_on_error,
+                                       description: 'Whether to fail the lane if the changelog cannot be computed. ' \
+                                                    'When `false` (the default), the error message is returned as the changelog itself, ' \
+                                                    'so that it ends up visible in the GitHub Release body. ' \
+                                                    'Set this to `true` if the caller publishes the release only after this action succeeds, ' \
+                                                    'and would rather stop than publish a release whose notes are an error message',
+                                       optional: true,
+                                       default_value: false,
+                                       type: Boolean),
           Fastlane::Helper::GithubHelper.github_token_config_item,
         ]
       end

spec/get_prs_between_tags_spec.rb

@@ -107,15 +107,24 @@ def test_with_params(target_commitish: nil, previous_tag: nil, configuration_fil
   end
 
   describe 'error handling' do
-    def test_with_params(target_commitish: nil, previous_tag: nil, configuration_file_path: nil, error_msg: 'API Failure')
-      # Arrange
+    def stub_failing_api_call(target_commitish: nil, previous_tag: nil, configuration_file_path: nil, error_msg: 'API Failure')
       allow(client).to receive(:post).with(
         "repos/#{test_repo}/releases/generate-notes",
         config_file_path: configuration_file_path,
         previous_tag_name: previous_tag,
         tag_name: test_tag_name,
         target_commitish: target_commitish || test_head_ref
       ).and_raise(StandardError, error_msg)
+    end
+
+    def test_with_params(target_commitish: nil, previous_tag: nil, configuration_file_path: nil, error_msg: 'API Failure')
+      # Arrange
+      stub_failing_api_call(
+        target_commitish: target_commitish,
+        previous_tag: previous_tag,
+        configuration_file_path: configuration_file_path,
+        error_msg: error_msg
+      )
 
       # Act
       result = run_described_fastlane_action(
@@ -154,5 +163,42 @@ def test_with_params(target_commitish: nil, previous_tag: nil, configuration_fil
         error_msg: '400 - Invalid previous_tag parameter'
       )
     end
+
+    context 'when `fail_on_error` is enabled' do
+      it 'raises instead of returning the error message as the changelog' do
+        # Arrange
+        stub_failing_api_call(previous_tag: '12.2', error_msg: 'API Failure')
+
+        # Act & Assert
+        expect do
+          run_described_fastlane_action(
+            github_token: test_token,
+            repository: test_repo,
+            tag_name: test_tag_name,
+            previous_tag: '12.2',
+            fail_on_error: true
+          )
+        end.to raise_error(StandardError, 'API Failure')
+      end
+    end
+
+    context 'when `fail_on_error` is explicitly disabled' do
+      it 'returns the error message as the changelog, like the default does' do
+        # Arrange
+        stub_failing_api_call(previous_tag: '12.2', error_msg: 'API Failure')
+
+        # Act
+        result = run_described_fastlane_action(
+          github_token: test_token,
+          repository: test_repo,
+          tag_name: test_tag_name,
+          previous_tag: '12.2',
+          fail_on_error: false
+        )
+
+        # Assert
+        expect(result).to eq('❌ Error computing the list of PRs since 12.2: `API Failure`')
+      end
+    end
   end
 end