Issue 8547: side effect import deps extracted

CHANGELOG.md

@@ -15,6 +15,7 @@
 
 ### Fixes
 
+- `[jest-cli]` Detect side-effect only imports when running `--onlyChanged` or `--changedSince` ([#8670](https://github.com/facebook/jest/pull/8670))
 - `[jest-cli]` Allow `--maxWorkers` to work with % input again ([#8565](https://github.com/facebook/jest/pull/8565))
 - `[babel-plugin-jest-hoist]` Expand list of whitelisted globals in global mocks ([#8429](https://github.com/facebook/jest/pull/8429)
 - `[jest-core]` Make watch plugin initialization errors look nice ([#8422](https://github.com/facebook/jest/pull/8422))

packages/jest-haste-map/src/lib/__tests__/dependencyExtractor.test.js

@@ -14,9 +14,13 @@ describe('dependencyExtractor', () => {
   it('should not extract dependencies inside comments', () => {
     const code = `
       // import a from 'ignore-line-comment';
+      // import 'ignore-line-comment';
+      // import './ignore-line-comment';
       // require('ignore-line-comment');
       /*
        * import a from 'ignore-block-comment';
+       * import './ignore-block-comment';
+       * import 'ignore-block-comment';
        * require('ignore-block-comment');
        */
     `;
@@ -67,6 +71,23 @@ describe('dependencyExtractor', () => {
     expect(extract(code)).toEqual(new Set(['dep1', 'dep2', 'dep3', 'dep4']));
   });
 
+  // https://github.com/facebook/jest/issues/8547
+  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#Import_a_module_for_its_side_effects_only
+  it('should extract dependencies from side-effect only `import` statements', () => {
+    const code = `
+        // Good
+        import './side-effect-dep1';
+        import 'side-effect-dep2';
+
+        // Bad
+        import ./inv1;
+        import inv2
+      `;
+    expect(extract(code)).toEqual(
+      new Set(['./side-effect-dep1', 'side-effect-dep2']),
+    );
+  });
+
   it('should not extract dependencies from `import type/typeof` statements', () => {
     const code = `
       // Bad

packages/jest-haste-map/src/lib/dependencyExtractor.ts

@@ -54,7 +54,7 @@ const REQUIRE_OR_DYNAMIC_IMPORT_RE = createRegExp(
 
 const IMPORT_OR_EXPORT_RE = createRegExp(
   [
-    '\\b(?:import|export)\\s+(?!type(?:of)?\\s+)[^\'"]+\\s+from\\s+',
+    '\\b(?:import|export)\\s+(?!type(?:of)?\\s+)(?:[^\'"]+\\s+from\\s+)?',
     CAPTURE_STRING_LITERAL(1),
   ],
   'g',