fix: exclude file movements for last updated time (#1023)

* Fix last updated time misleading, only show when file content change
or otherwise when it is first created

Fix #1015

* Fix prettier

* - Simplify regex
- Uses shelljs instead of cross-spawn
- Make logic clearer

* Add test when repositories is moved

* Use shell.exec mock

I initially try to mock the whole shelljs. But it returns error
shell.exec is not a function when i try to provide the mockResolvedValue
I think it is because of the inner code of shelljs who run a forEach to
require each of its method which make it a promise. I tried moving the
jest.mock inside beforeAll and also adding babel-dynamic-import but it did
not solve the problem. In the end, I decided to just mock shelljs.exec since
it is the only function used anyway

v1/lib/core/__tests__/utils.test.js

@@ -7,6 +7,7 @@
 
 const path = require('path');
 const fs = require('fs');
+const shell = require('shelljs');
 const utils = require('../utils');
 
 const blogPostWithTruncateContents = fs.readFileSync(
@@ -96,6 +97,40 @@ describe('utils', () => {
     fs.writeFileSync(tempFilePath, 'Lorem ipsum :)');
     expect(utils.getGitLastUpdated(tempFilePath)).toBeNull();
     fs.unlinkSync(tempFilePath);
+
+    // test renaming and moving file
+
+    const tempFilePath2 = path.join(__dirname, '__fixtures__', '.temp2');
+    const tempFilePath3 = path.join(
+      __dirname,
+      '__fixtures__',
+      'test',
+      '.temp3',
+    );
+
+    // create new file
+    shell.exec = jest.fn(() => ({
+      stdout:
+        '1539502055\n' +
+        '\n' +
+        ' create mode 100644 v1/lib/core/__tests__/__fixtures__/.temp2\n',
+    }));
+    const createTime = utils.getGitLastUpdated(tempFilePath2);
+    expect(typeof createTime).toBe('string');
+
+    // rename / move the file
+    shell.exec = jest.fn(() => ({
+      stdout:
+        '1539502056\n' +
+        '\n' +
+        ' rename v1/lib/core/__tests__/__fixtures__/{.temp2 => test/.temp3} (100%)\n' +
+        '1539502055\n' +
+        '\n' +
+        ' create mode 100644 v1/lib/core/__tests__/__fixtures__/.temp2\n',
+    }));
+    const lastUpdateTime = utils.getGitLastUpdated(tempFilePath3);
+    // should only consider file content change
+    expect(lastUpdateTime).toEqual(createTime);
   });
 
   test('idx', () => {

v1/lib/core/utils.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
-const spawn = require('cross-spawn');
+const shell = require('shelljs');
 
 const TRUNCATE_MARKER = /<!--\s*truncate\s*-->/;
 
@@ -38,10 +38,34 @@ function idx(target, keyPaths) {
   );
 }
 
+function isNormalInteger(str) {
+  return /^\d+$/.test(str);
+}
+
 function getGitLastUpdated(filepath) {
-  const timeSpan = spawn
-    .sync('git', ['log', '-1', '--format=%ct', filepath])
-    .stdout.toString('utf-8');
+  // To differentiate between content change and file renaming / moving, use --summary
+  // To follow the file history until before it is moved (when we create new version), use
+  // --follow
+  const silentState = shell.config.silent; // save old silent state
+  shell.config.silent = true;
+  const result = shell
+    .exec(`git log --follow --summary --format=%ct ${filepath}`)
+    .stdout.trim();
+  shell.config.silent = silentState;
+
+  // Format the log results to be ['1234567', 'rename ...', '1234566', 'move ...', '1234565', '1234564']
+  const records = result
+    .toString('utf-8')
+    .replace(/\n\s*\n/g, '\n')
+    .split('\n')
+    .filter(String);
+
+  const timeSpan = records.find((item, index, arr) => {
+    const isTimestamp = isNormalInteger(item);
+    const isLastTwoItem = index + 2 >= arr.length;
+    const nextItemIsTimestamp = isNormalInteger(arr[index + 1]);
+    return isTimestamp && (isLastTwoItem || nextItemIsTimestamp);
+  });
   if (timeSpan) {
     const date = new Date(parseInt(timeSpan, 10) * 1000);
     return date.toLocaleString();