fix(jest-changed-files): improve changedFilesWithAncestor command pattern for Mercurial SCM (#12322)

Author: mrazauskas

Diff for: CHANGELOG.md

@@ -68,6 +68,7 @@
 - `[expect]` Throw useful error if `expect.extend` is called with invalid matchers ([#12488](https://github.com/facebook/jest/pull/12488))
 - `[expect]` Fix `iterableEquality` ignores other properties ([#8359](https://github.com/facebook/jest/pull/8359))
 - `[expect]` Fix print for the `closeTo` matcher ([#12626](https://github.com/facebook/jest/pull/12626))
+- `[jest-changed-files]` Improve `changedFilesWithAncestor` pattern for Mercurial SCM ([#12322](https://github.com/facebook/jest/pull/12322))
 - `[jest-circus, @jest/types]` Disallow undefined value in `TestContext` type ([#12507](https://github.com/facebook/jest/pull/12507))
 - `[jest-config]` Correctly detect CI environment and update snapshots accordingly ([#12378](https://github.com/facebook/jest/pull/12378))
 - `[jest-config]` Pass `moduleTypes` to `ts-node` to enforce CJS when transpiling ([#12397](https://github.com/facebook/jest/pull/12397))

Diff for: e2e/__tests__/jestChangedFiles.test.ts

@@ -362,14 +362,6 @@ test('handles a bad revision for "changedSince", for git', async () => {
 });
 
 testIfHg('gets changed files for hg', async () => {
-  if (process.env.CI) {
-    // Circle and Travis have very old version of hg (v2, and current
-    // version is v4.2) and its API changed since then and not compatible
-    // any more. Changing the SCM version on CIs is not trivial, so we'll just
-    // skip this test and run it only locally.
-    return;
-  }
-
   // file1.txt is used to make a multi-line commit message
   // with `hg commit -l file1.txt`.
   // This is done to ensure that `changedFiles` only returns files

Diff for: packages/jest-changed-files/src/hg.ts

@@ -18,7 +18,7 @@ const adapter: SCMAdapter = {
 
     const args = ['status', '-amnu'];
     if (options.withAncestor) {
-      args.push('--rev', 'min((!public() & ::.)+.)^');
+      args.push('--rev', 'first(min(!public() & ::.)^+.^)');
     } else if (options.changedSince) {
       args.push('--rev', `ancestor(., ${options.changedSince})`);
     } else if (options.lastCommit === true) {