feat: ✨ Support PR Template on pull request creation (#997)

Author: robvanderleek

README.md

@@ -564,7 +564,8 @@ branches:
 
 ### Copy attributes from issue
 
-When the App opens a new (draft) Pull Request it can also copy over the following attributes from your issue:
+When the App opens a new (draft) Pull Request, it can also copy over the
+following attributes from your issue:
 
 - Description
 - Labels
@@ -582,6 +583,18 @@ copyIssueProjectsToPR: true
 copyIssueMilestoneToPR: true
 ```
 
+### Copy pull request template
+
+When the App opens a new (draft) Pull Request, it can also copy over a pull
+request template from a file in your repository. The template must be stored in
+a file named `.github/pull_request_template.md`.
+
+You can enable this behaviour in the configuration:
+
+```yaml
+copyPullRequestTemplateToPR: true
+```
+
 ### Skip CI workflows
 
 Automatically opening a (draft) PR for an issue requires an empty commit on the newly created branch (this is a

src/entities/Config.ts

@@ -11,6 +11,7 @@ export interface Config {
     copyIssueProjectsToPR: boolean;
     copyIssueMilestoneToPR: boolean;
     copyIssueDescriptionToPR: boolean;
+    copyPullRequestTemplateToPR: boolean;
     gitReplaceChars: string;
     gitSafeReplacementChar: string;
     commentMessage?: string;
@@ -49,6 +50,7 @@ export function getDefaultConfig(): Config {
         copyIssueProjectsToPR: false,
         copyIssueMilestoneToPR: false,
         copyIssueDescriptionToPR: false,
+        copyPullRequestTemplateToPR: false,
         gitReplaceChars: '',
         gitSafeReplacementChar: '_',
         silent: false,

src/github.ts

@@ -276,7 +276,7 @@ export async function createPr(app: Probot, ctx: Context<any>, config: Config, u
             await createEmptyCommit(ctx, branchName, getCommitText(ctx, config), String(branchHeadSha))
         }
         const {data: pr} = await ctx.octokit.pulls.create(
-            {owner, repo, head: branchName, base, title, body: getPrBody(app, ctx, config), draft: draft})
+            {owner, repo, head: branchName, base, title, body: await getPrBody(app, ctx, config), draft: draft})
         app.log.info(`${draft ? 'Created draft' : 'Created'} pull request ${pr.number} for branch ${branchName}`)
         await copyIssueAttributesToPr(app, ctx, config, pr)
     } catch (e: any) {
@@ -320,19 +320,43 @@ function getCommitText(ctx: Context<any>, config: Config) {
     }
 }
 
-function getPrBody(app: Probot, ctx: Context<any>, config: Config) {
-    const issueNumber = getIssueNumber(ctx)
-    let result = ''
+async function getPrBody(app: Probot, ctx: Context<any>, config: Config) {
+    const issueNumber = getIssueNumber(ctx);
+    let result = '';
     if (config.copyIssueDescriptionToPR) {
-        app.log.info('Copying issue description to PR')
-        const issueDescription = getIssueDescription(ctx)
+        app.log.info('Copying issue description to PR');
+        const issueDescription = getIssueDescription(ctx);
         if (issueDescription) {
-            result += formatAsExpandingMarkdown('Original issue description', issueDescription)
-            result += '\n'
+            result += formatAsExpandingMarkdown('Original issue description', issueDescription);
+            result += '\n';
         }
     }
-    result += `closes #${issueNumber}`
-    return result
+    if (config.copyPullRequestTemplateToPR) {
+        app.log.info('Copying pull-request template to PR');
+        const pullRequestTemplate = await getPullRequestTemplate(ctx);
+        if (pullRequestTemplate) {
+            result += pullRequestTemplate;
+            result += '\n';
+        }
+    }
+    result += `closes #${issueNumber}`;
+    return result;
+}
+
+async function getPullRequestTemplate(ctx: Context<any>): Promise<string | undefined> {
+    try {
+        const {data} = await ctx.octokit.repos.getContent({
+            owner: getRepoOwnerLogin(ctx),
+            repo: getRepoName(ctx),
+            path: '.github/pull_request_template.md'
+        }) as any;
+        if (data.type === 'file' && data.content) {
+            return Buffer.from(data.content, 'base64').toString('utf8');
+        }
+    } catch (e: any) {
+        /* do nothing */
+    }
+    return undefined;
 }
 
 async function copyIssueAttributesToPr(app: Probot, ctx: Context<any>, config: Config, pr: any) {

tests/github.test.ts

@@ -296,6 +296,7 @@ test('copy Issue description into PR', async () => {
     })
 })
 
+
 test('Do not copy undefined Issue description into PR', async () => {
     const createPR = jest.fn()
     const ctx = getDefaultContext()
@@ -317,6 +318,56 @@ test('Do not copy undefined Issue description into PR', async () => {
     })
 })
 
+test('copy pull-request template into PR', async () => {
+    const createPR = jest.fn();
+    const ctx = getDefaultContext();
+    ctx.octokit.pulls.create = createPR;
+    ctx.octokit.graphql = jest.fn();
+    ctx.octokit.repos.getContent = async (args: { owner: string, repo: string, path: string }) => {
+        expect(args.path).toBe('.github/pull_request_template.md');
+        return {data: {type: 'file', content: Buffer.from('file content').toString('base64')}};
+    };
+    const config = getDefaultConfig();
+    config.copyPullRequestTemplateToPR = true;
+
+    await github.createPr(probot, ctx, config, 'robvanderleek', 'issue-1');
+
+    expect(createPR).toHaveBeenCalledWith({
+        owner: 'robvanderleek',
+        repo: 'create-issue-branch',
+        head: 'issue-1',
+        base: 'master',
+        title: 'Hello world',
+        body: 'file content' + '\ncloses #1',
+        draft: false
+    });
+})
+
+test('pull-request template does not exist', async () => {
+    const createPR = jest.fn();
+    const ctx = getDefaultContext();
+    ctx.octokit.pulls.create = createPR;
+    ctx.octokit.graphql = jest.fn();
+    ctx.octokit.repos.getContent = async (args: { owner: string, repo: string, path: string }) => {
+        expect(args.path).toBe('.github/pull_request_template.md');
+        throw {status: 404};
+    };
+    const config = getDefaultConfig();
+    config.copyPullRequestTemplateToPR = true;
+
+    await github.createPr(probot, ctx, config, 'robvanderleek', 'issue-1');
+
+    expect(createPR).toHaveBeenCalledWith({
+        owner: 'robvanderleek',
+        repo: 'create-issue-branch',
+        head: 'issue-1',
+        base: 'master',
+        title: 'Hello world',
+        body: 'closes #1',
+        draft: false
+    });
+})
+
 test('use correct source branch', async () => {
     const createPR = jest.fn()
     const ctx = getDefaultContext()

tests/test-helpers.ts

@@ -163,6 +163,7 @@ export function getDefaultContext(): any {
                 createComment: () => {
                 }
             },
+            repos: {},
             graphql: (_: any, {message}: { message: string }) => {
             }
         }, //