feat(create-and-merge-pull-request): support configurable merge methods

README.md

@@ -21,7 +21,7 @@ Opinionated GitHub Actions and reusable workflows for foundational continuous-in
 ### Workflow & repository automation
 
 - [Checkout](actions/checkout/README.md) - event-aware drop-in replacement for `actions/checkout` that supports issue comment triggers.
-- [Create and merge pull request](actions/create-and-merge-pull-request/README.md) - opens a pull request, rebases, and merges it with the GitHub Actions bot identity.
+- [Create and merge pull request](actions/create-and-merge-pull-request/README.md) - opens a pull request and merges it with the configured strategy and GitHub Actions bot identity.
 - [Create or update comment](actions/create-or-update-comment/README.md) - adds or updates comments on issues and pull requests idempotently.
 - [Get GitHub Actions bot user](actions/get-github-actions-bot-user/README.md) - retrieves the profile information for the GitHub Actions bot.
 - [Get issue number](actions/get-issue-number/README.md) - extracts the relevant issue number from the current workflow context.

actions/create-and-merge-pull-request/README.md

@@ -26,7 +26,7 @@
 ## Overview
 
 Action to create and merge Pull Request.
-Opinionated, set GitHub Actions bot as author, then rebase and merge.
+Opinionated, set GitHub Actions bot as author, then merge with the configured strategy.
 
 For this action to work you must explicitly allow GitHub Actions to create pull requests.
 See <https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/enabling-features-for-your-repository/managing-github-actions-settings-for-a-repository>.
@@ -50,17 +50,23 @@ See <https://docs.github.com/en/repositories/managing-your-repositorys-settings-
     # This input is required.
     branch: ""
 
-    # The pull request title
+    # The pull request title and, for merge/squash merges, the merged commit title
     # This input is required.
     title: ""
 
     # The pull request body
     # This input is required.
     body: ""
 
-    # The commit message for the pull request
+    # The commit message for the pull request and, for merge/squash merges, the merged commit body
     # This input is required.
     commit-message: ""
+
+    # Merge strategy for the created pull request.
+    # Valid values: `merge`, `rebase`, `squash`.
+    #
+    # Default: `rebase`
+    merge-method: rebase
 ```
 
 <!-- usage:end -->
@@ -75,8 +81,12 @@ See <https://docs.github.com/en/repositories/managing-your-repositorys-settings-
 |                      | See <https://github.com/peter-evans/create-pull-request#action-inputs>.                                    |              |                       |
 | **`branch`**         | The pull request branch name                                                                               | **true**     | -                     |
 | **`title`**          | The pull request title                                                                                     | **true**     | -                     |
+|                      | Also used as the merged commit title for `merge` and `squash`.                                             |              |                       |
 | **`body`**           | The pull request body                                                                                      | **true**     | -                     |
 | **`commit-message`** | The commit message for the pull request                                                                    | **true**     | -                     |
+|                      | Also used as the merged commit body for `merge` and `squash`.                                              |              |                       |
+| **`merge-method`**   | Merge strategy for the created pull request.                                                               | **false**    | `rebase`              |
+|                      | Valid values: `merge`, `rebase`, `squash`.                                                                 |              |                       |
 
 <!-- inputs:end -->
 

actions/create-and-merge-pull-request/action.yml

@@ -3,7 +3,7 @@
 name: "Create and merge Pull Request"
 description: |
   Action to create and merge Pull Request.
-  Opinionated, set GitHub Actions bot as author, then rebase and merge.
+  Opinionated, set GitHub Actions bot as author, then merge with the configured strategy.
 author: hoverkraft
 branding:
   icon: git-pull-request
@@ -20,14 +20,20 @@ inputs:
     description: "The pull request branch name"
     required: true
   title:
-    description: "The pull request title"
+    description: "The pull request title and, for merge/squash merges, the merged commit title"
     required: true
   body:
     description: "The pull request body"
     required: true
   commit-message:
-    description: "The commit message for the pull request"
+    description: "The commit message for the pull request and, for merge/squash merges, the merged commit body"
     required: true
+  merge-method:
+    description: |
+      Merge strategy for the created pull request.
+      Valid values: `merge`, `rebase`, `squash`.
+    default: rebase
+    required: false
 
 outputs:
   merged-ref:
@@ -82,16 +88,33 @@ runs:
       env:
         GH_TOKEN: ${{ inputs.github-token }}
         PULL_REQUEST_NUMBER: ${{ steps.create-pull-request.outputs.pull-request-number }}
+        MERGE_METHOD: ${{ inputs.merge-method }}
+        PULL_REQUEST_TITLE: ${{ inputs.title }}
+        PULL_REQUEST_COMMIT_MESSAGE: ${{ inputs.commit-message }}
       with:
         github-token: ${{ inputs.github-token }}
         script: |
           const maxAttempts = 10;
           const requiredWorkflowsError = 'Required workflow';
           const repository = `${context.repo.owner}/${context.repo.repo}`;
+          const mergeMethod = (process.env.MERGE_METHOD ?? 'rebase').trim();
+          const mergeCommitTitle = (process.env.PULL_REQUEST_TITLE ?? '').trim();
+          const mergeCommitMessage = process.env.PULL_REQUEST_COMMIT_MESSAGE ?? '';
+          const mergeMethodFlags = {
+            merge: '--merge',
+            rebase: '--rebase',
+            squash: '--squash',
+          };
           const getRetryDelayMs = attempt => Math.min(1000 * (2 ** attempt), 10000);
 
           const sleep = delayMs => new Promise(resolve => setTimeout(resolve, delayMs));
 
+          if (!(mergeMethod in mergeMethodFlags)) {
+            throw new Error(
+              `Invalid merge method: ${mergeMethod}. Expected one of: ${Object.keys(mergeMethodFlags).join(', ')}`,
+            );
+          }
+
           const waitFor = async ({
             run,
             isComplete,
@@ -154,20 +177,34 @@ runs:
               getTimeoutMessage: () => `Pull request #${pullNumber} is not mergeable after ${maxAttempts} attempts`,
             });
 
+          const getMergeArguments = pullNumber => {
+            const args = [
+              'pr',
+              'merge',
+              '-R',
+              repository,
+              mergeMethodFlags[mergeMethod],
+              '--admin',
+              String(pullNumber),
+            ];
+
+            if (mergeMethod !== 'rebase' && mergeCommitTitle) {
+              args.push('--subject', mergeCommitTitle);
+            }
+
+            if (mergeMethod !== 'rebase' && mergeCommitMessage.trim()) {
+              args.push('--body', mergeCommitMessage);
+            }
+
+            return args;
+          };
+
           const mergePullRequest = async pullNumber => {
-            core.debug(`Merging pull request #${pullNumber} for repository ${repository}...`);
+            core.debug(`Merging pull request #${pullNumber} for repository ${repository} with method ${mergeMethod}...`);
 
             const { exitCode, stdout, stderr } = await exec.getExecOutput(
               'gh',
-              [
-                'pr',
-                'merge',
-                '-R',
-                repository,
-                '--rebase',
-                '--admin',
-                String(pullNumber),
-              ],
+              getMergeArguments(pullNumber),
               {
                 env: process.env,
                 ignoreReturnCode: true,