fix: use git to check that you're in a Git repository (#689)

* test(core): added init-git tests to cover known cases

* test(core): add failing test for init-git

catches case where init-git is run within a subdirectory of a known
repository and forge should not create a nested .git directory

* fix(core): do not initialize when in an existing git repository

packages/api/core/src/api/init-scripts/init-git.ts

@@ -1,24 +1,28 @@
 import { asyncOra } from '@electron-forge/async-ora';
 import { exec } from 'child_process';
 import debug from 'debug';
-import fs from 'fs-extra';
-import path from 'path';
 
 const d = debug('electron-forge:init:git');
 
 export default async (dir: string) => {
   await asyncOra('Initializing Git Repository', async () => {
-    await new Promise(async (resolve, reject) => {
-      if (await fs.pathExists(path.resolve(dir, '.git'))) {
-        d('.git directory already exists, skipping git initialization');
-        return resolve();
-      }
-      d('executing "git init" in directory:', dir);
-      exec('git init', {
+    await new Promise((resolve, reject) => {
+      exec('git rev-parse --show-toplevel', {
         cwd: dir,
       }, (err) => {
-        if (err) return reject(err);
-        resolve();
+        if (err) {
+          // not run within a Git repository
+          d('executing "git init" in directory:', dir);
+          exec('git init', {
+            cwd: dir,
+          }, (err) => {
+            if (err) return reject(err);
+            resolve();
+          });
+        } else {
+          d('.git directory already exists, skipping git initialization');
+          resolve();
+        }
       });
     });
   });

packages/api/core/test/slow/init_git_spec_slow.ts

@@ -0,0 +1,68 @@
+import { execSync } from 'child_process';
+import fs from 'fs-extra';
+import os from 'os';
+import path from 'path';
+
+import { expect } from 'chai';
+
+import initGit from '../../src/api/init-scripts/init-git';
+
+let dir: string;
+let dirID = Date.now();
+
+const ensureTestDirIsNonexistent = async () => {
+  dir = path.resolve(os.tmpdir(), `electron-forge-git-test-${dirID}`);
+  dirID += 1;
+  await fs.remove(dir);
+};
+
+describe('init-git', () => {
+  beforeEach(async () => {
+    await ensureTestDirIsNonexistent();
+    await fs.mkdir(dir);
+  });
+
+  it('creates Git repository when run inside non-Git directory', async () => {
+    await initGit(dir);
+    const gitDir = path.join(dir, '.git');
+    expect(await fs.pathExists(gitDir), 'the .git directory inside the folder').to.equal(true);
+  });
+
+  it('skips when run at root of Git repository', async () => {
+    await execSync('git init', { cwd: dir });
+
+    const gitDir = path.join(dir, '.git');
+    const config = path.join(gitDir, 'config');
+    const statBefore = await fs.lstat(config);
+    const before = statBefore.mtimeMs;
+
+    await initGit(dir);
+
+    const statAfter = await fs.lstat(config);
+    const after = statAfter.mtimeMs;
+
+    expect(after, 'the config file in the repository').to.equal(before);
+  });
+
+  it('skips when run in subdirectory of Git repository', async () => {
+    await execSync('git init', { cwd: dir });
+
+    const gitDir = path.join(dir, '.git');
+    const config = path.join(gitDir, 'config');
+    const statBefore = await fs.lstat(config);
+    const before = statBefore.mtimeMs;
+
+    const subdir = path.join(dir, 'some', 'other', 'folder');
+    const innerGitDir = path.join(subdir, '.git');
+
+    await fs.mkdirp(subdir);
+
+    await initGit(subdir);
+
+    const statAfter = await fs.lstat(config);
+    const after = statAfter.mtimeMs;
+
+    expect(after, 'the config file in the repository').to.equal(before);
+    expect(await fs.pathExists(innerGitDir), 'a nested .git directory inside the repository').to.equal(false);
+  });
+});