fix: getRefs function to handle merge_group events

__tests__/config.test.ts

@@ -128,6 +128,51 @@ test('it raises an error when no refs are provided and the event is not a pull r
   ).toThrow()
 })
 
+const pullRequestLikeEvents = [
+  'pull_request',
+  'pull_request_target',
+  'merge_group'
+]
+
+test.each(pullRequestLikeEvents)(
+  'it uses the given refs even when the event is %s',
+  async eventName => {
+    setInput('base-ref', 'a-custom-base-ref')
+    setInput('head-ref', 'a-custom-head-ref')
+
+    const refs = getRefs(await readConfig(), {
+      payload: {
+        pull_request: {
+          number: 42,
+          base: {sha: 'pr-base-ref'},
+          head: {sha: 'pr-head-ref'}
+        }
+      },
+      eventName
+    })
+    expect(refs.base).toEqual('a-custom-base-ref')
+    expect(refs.head).toEqual('a-custom-head-ref')
+  }
+)
+
+test.each(pullRequestLikeEvents)(
+  'it uses the event refs when the event is %s and the no refs are input',
+  async eventName => {
+    const refs = getRefs(await readConfig(), {
+      payload: {
+        pull_request: {
+          number: 42,
+          base: {sha: 'pr-base-ref'},
+          head: {sha: 'pr-head-ref'}
+        }
+      },
+      eventName
+    })
+    expect(refs.base).toEqual('pr-base-ref')
+    expect(refs.head).toEqual('pr-head-ref')
+  }
+)
+
 test('it defaults to runtime scope', async () => {
   const config = await readConfig()
   expect(config.fail_on_scopes).toEqual(['runtime'])

src/git-refs.ts

@@ -11,7 +11,8 @@ export function getRefs(
   // The base/head ref from the config take priority, if provided.
   if (
     context.eventName === 'pull_request' ||
-    context.eventName === 'pull_request_target'
+    context.eventName === 'pull_request_target' ||
+    context.eventName === 'merge_group'
   ) {
     const pull_request = PullRequestSchema.parse(context.payload.pull_request)
     base_ref = base_ref || pull_request.base.sha
@@ -22,19 +23,19 @@ export function getRefs(
     throw new Error(
       'Both a base ref and head ref must be provided, either via the `base_ref`/`head_ref` ' +
         'config options, `base-ref`/`head-ref` workflow action options, or by running a ' +
-        '`pull_request`/`pull_request_target` workflow.'
+        '`pull_request`/`pull_request_target`/`merge_group` workflow.'
     )
   } else if (!base_ref) {
     throw new Error(
       'A base ref must be provided, either via the `base_ref` config option, ' +
         '`base-ref` workflow action option, or by running a ' +
-        '`pull_request`/`pull_request_target` workflow.'
+        '`pull_request`/`pull_request_target`/`merge_group` workflow.'
     )
   } else if (!head_ref) {
     throw new Error(
       'A head ref must be provided, either via the `head_ref` config option, ' +
         '`head-ref` workflow action option, or by running a ' +
-        'or by running a `pull_request`/`pull_request_target` workflow.'
+        'or by running a `pull_request`/`pull_request_target`/`merge_group` workflow.'
     )
   }