feat: Create/Pass commit date to commit for signing

src/github/create-commit.ts

@@ -32,6 +32,7 @@ export interface CreateCommitOptions {
  * @param {string} refHead the base of the new commit(s)
  * @param {string} treeSha the tree SHA that this commit will point to
  * @param {string} message the message of the new commit
+ * @param {CreateCommitOptions} options additional options like author or commit signer
  * @returns {Promise<string>} the new commit SHA
  * @see https://docs.github.com/en/rest/git/commits?apiVersion=2022-11-28#create-a-commit
  */
@@ -44,15 +45,37 @@ export async function createCommit(
   options: CreateCommitOptions = {}
 ): Promise<string> {
   try {
-    const signature = options.signer
-      ? await options.signer.generateSignature({
-          message,
-          tree: treeSha,
-          parents: [refHead],
-          author: options.author,
-          committer: options.committer,
-        })
-      : undefined;
+    let signature: string | undefined;
+    let author: Required<UserData> | undefined = undefined;
+    let committer: Required<UserData> | undefined = undefined;
+
+    const commitDate = new Date();
+    // Attach author/commit date.
+    if (options.author) {
+      author = {
+        ...options.author,
+        date: options.author.date ?? commitDate,
+      };
+    }
+    if (options.committer) {
+      committer = {
+        ...options.committer,
+        date: options.committer.date ?? commitDate,
+      };
+    }
+
+    if (options.signer) {
+      signature = await options.signer.generateSignature({
+        message,
+        tree: treeSha,
+        parents: [refHead],
+        author,
+        committer,
+      });
+    } else {
+      signature = undefined;
+    }
+
     const {
       data: {sha, url},
     } = await octokit.git.createCommit({
@@ -62,8 +85,10 @@ export async function createCommit(
       tree: treeSha,
       parents: [refHead],
       signature,
-      author: options.author,
-      committer: options.committer,
+      author: author ? {...author, date: author.date.toISOString()} : author,
+      committer: committer
+        ? {...committer, date: committer.date.toISOString()}
+        : committer,
     });
     logger.info(`Successfully created commit. See commit at ${url}`);
     return sha;

src/index.ts

@@ -22,7 +22,12 @@ import {
   FileDiffContent,
   CreateReviewCommentUserOptions,
 } from './types';
-export {Changes, CommitData, CommitSigner} from './types';
+export {
+  Changes,
+  CommitData,
+  CommitDataWithRequiredDate,
+  CommitSigner,
+} from './types';
 import {Octokit} from '@octokit/rest';
 import {logger, setupLogger} from './logger';
 import {

src/types.ts

@@ -206,6 +206,7 @@ export interface Logger {
 export interface UserData {
   name: string;
   email: string;
+  date?: Date;
 }
 
 export interface CommitData {
@@ -216,6 +217,11 @@ export interface CommitData {
   committer?: UserData;
 }
 
+export interface CommitDataWithRequiredDate extends CommitData {
+  author?: Required<UserData>;
+  committer?: Required<UserData>;
+}
+
 export interface CommitSigner {
-  generateSignature(commit: CommitData): Promise<string>;
+  generateSignature(commit: CommitDataWithRequiredDate): Promise<string>;
 }

test/commit-and-push.ts

@@ -15,7 +15,7 @@
 /* eslint-disable node/no-unsupported-features/node-builtins */
 
 import * as assert from 'assert';
-import {describe, it, before, afterEach} from 'mocha';
+import {describe, it, before, afterEach, beforeEach} from 'mocha';
 import {octokit, setup} from './util';
 import * as sinon from 'sinon';
 import {GetResponseTypeFromEndpointMethod} from '@octokit/types';
@@ -31,6 +31,7 @@ import {
 } from '../src/types';
 import {createCommit} from '../src/github/create-commit';
 import {CommitError} from '../src/errors';
+import {SinonFakeTimers} from 'sinon';
 
 type GetCommitResponse = GetResponseTypeFromEndpointMethod<
   typeof octokit.git.getCommit
@@ -190,8 +191,13 @@ describe('Push', () => {
 
 describe('Commit', () => {
   const sandbox = sinon.createSandbox();
+  let clock: SinonFakeTimers;
+  beforeEach(() => {
+    clock = sinon.useFakeTimers();
+  });
   afterEach(() => {
     sandbox.restore();
+    clock.restore();
   });
   const origin: RepoDomain = {
     owner: 'Foo',
@@ -225,6 +231,43 @@ describe('Commit', () => {
       parents: [head],
     });
   });
+  it('Uses current date when date in author/committer is undefined and commit signing is enabled', async () => {
+    // setup
+    const createCommitResponseData = await import(
+      './fixtures/create-commit-response.json'
+    );
+    const createCommitResponse = {
+      headers: {},
+      status: 201,
+      url: 'http://fake-url.com',
+      data: createCommitResponseData,
+    } as unknown as CreateCommitResponse;
+    const stubCreateCommit = sandbox
+      .stub(octokit.git, 'createCommit')
+      .resolves(createCommitResponse);
+    // tests
+    const sha = await createCommit(octokit, origin, head, treeSha, message, {
+      author: {
+        name: 'Fake Author',
+        email: 'fake.email@example.com',
+      },
+      signer: new FakeCommitSigner('fake-signature'),
+    });
+    assert.strictEqual(sha, createCommitResponse.data.sha);
+    sandbox.assert.calledOnceWithMatch(stubCreateCommit, {
+      owner: origin.owner,
+      repo: origin.repo,
+      message,
+      tree: treeSha,
+      parents: [head],
+      author: {
+        name: 'Fake Author',
+        email: 'fake.email@example.com',
+        date: new Date(clock.now).toISOString(),
+      },
+      signature: 'fake-signature',
+    });
+  });
 });
 
 describe('Update branch reference', () => {