Sourcemaps

package.json

@@ -73,6 +73,7 @@
     "rollup-plugin-node-globals": "^1.1.0",
     "rollup-plugin-node-resolve": "^3.0.0",
     "slash": "^1.0.0",
+    "source-map-support": "^0.5.0",
     "string-length": "^2.0.0",
     "strip-ansi": "^4.0.0",
     "typescript": "^2.2.2",

packages/jest-jasmine2/src/index.js

@@ -15,6 +15,7 @@ import type {TestResult} from 'types/TestResult';
 import type Runtime from 'jest-runtime';
 
 import path from 'path';
+import fs from 'fs';
 import JasmineReporter from './reporter';
 import {install as jasmineAsyncInstall} from './jasmine_async';
 
@@ -93,6 +94,25 @@ async function jasmine2(
     runtime.requireModule(config.setupTestFrameworkScriptFile);
   }
 
+  runtime
+    .requireModule(require.resolve('source-map-support'), 'source-map-support')
+    .install({
+      handleUncaughtExceptions: false,
+      retrieveSourceMap: source => {
+        if (runtime._sourceMapRegistry[source]) {
+          try {
+            return {
+              map: JSON.parse(
+                fs.readFileSync(runtime._sourceMapRegistry[source]),
+              ),
+              url: source,
+            };
+          } catch (e) {}
+        }
+        return null;
+      },
+    });
+
   if (globalConfig.testNamePattern) {
     const testNameRegex = new RegExp(globalConfig.testNamePattern, 'i');
     env.specFilter = spec => testNameRegex.test(spec.getFullName());

packages/jest-runtime/src/__tests__/Runtime-sourceMaps-test.js

@@ -0,0 +1,47 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails oncall+jsinfra
+ */
+'use strict';
+
+let createRuntime;
+
+describe('Runtime', () => {
+  beforeEach(() => {
+    createRuntime = require('createRuntime');
+  });
+
+  describe('requireModule', () => {
+    it('installs source maps if available', () =>
+      createRuntime(__filename).then(runtime => {
+        let hasThrown = false;
+        const sum = runtime.requireModule(
+          runtime.__mockRootPath,
+          './sourcemaps/out/throwing-mapped-fn.js',
+        ).sum;
+
+        try {
+          sum();
+        } catch (err) {
+          hasThrown = true;
+          /* eslint-disable max-len */
+          if (process.platform === 'win32') {
+            expect(err.stack).toMatch(
+              /^Error: throwing fn\s+at sum.+\\__tests__\\test_root\\sourcemaps\\throwing-mapped-fn.js:10:9/,
+            );
+          } else {
+            expect(err.stack).toMatch(
+              /^Error: throwing fn\s+at sum.+\/__tests__\/test_root\/sourcemaps\/throwing-mapped-fn.js:10:9/,
+            );
+          }
+          /* eslint-enable max-len */
+        }
+        expect(hasThrown).toBe(true);
+      }));
+  });
+});

packages/jest-runtime/src/__tests__/script_transformer.test.js

@@ -334,7 +334,7 @@ describe('ScriptTransformer', () => {
     ).toBeCalledWith(result.sourceMapPath, sourceMap, {encoding: 'utf8'});
   });
 
-  it('does not write source map if mapCoverage option is false', () => {
+  it('writes source maps if given by the transformer', () => {
     config = Object.assign(config, {
       transform: [['^.+\\.js$', 'preprocessor-with-sourcemaps']],
     });
@@ -350,6 +350,29 @@ describe('ScriptTransformer', () => {
       map,
     });
 
+    const result = scriptTransformer.transform('/fruits/banana.js', {
+      collectCoverage: true,
+      mapCoverage: false,
+    });
+    expect(result.sourceMapPath).toEqual(expect.any(String));
+    expect(writeFileAtomic.sync).toBeCalledWith(
+      result.sourceMapPath,
+      JSON.stringify(map),
+      {encoding: 'utf8'},
+    );
+  });
+
+  it('does not write source map if not given by the transformer', () => {
+    config = Object.assign(config, {
+      transform: [['^.+\\.js$', 'preprocessor-with-sourcemaps']],
+    });
+    const scriptTransformer = new ScriptTransformer(config);
+
+    require('preprocessor-with-sourcemaps').process.mockReturnValue({
+      code: 'content',
+      map: null,
+    });
+
     const result = scriptTransformer.transform('/fruits/banana.js', {
       collectCoverage: true,
       mapCoverage: false,

packages/jest-runtime/src/__tests__/test_root/sourcemaps/throwing-mapped-fn.js

@@ -0,0 +1,11 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+export function sum() {
+  throw new Error('throwing fn');
+}

packages/jest-runtime/src/script_transformer.js

@@ -238,8 +238,6 @@ export default class ScriptTransformer {
           transformed.map = inlineSourceMap.toJSON();
         }
       }
-    } else {
-      transformed.map = null;
     }
 
     // That means that the transform has a custom instrumentation
@@ -252,7 +250,7 @@ export default class ScriptTransformer {
       code = transformed.code;
     }
 
-    if (instrument && transformed.map && mapCoverage) {
+    if (transformed.map) {
       const sourceMapContent =
         typeof transformed.map === 'string'
           ? transformed.map

yarn.lock

@@ -5432,6 +5432,12 @@ source-map-support@^0.4.15:
   dependencies:
     source-map "^0.5.6"
 
+source-map-support@^0.5.0:
+  version "0.5.0"
+  resolved "https://registry.yarnpkg.com/source-map-support/-/source-map-support-0.5.0.tgz#2018a7ad2bdf8faf2691e5fddab26bed5a2bacab"
+  dependencies:
+    source-map "^0.6.0"
+
 source-map@^0.4.4:
   version "0.4.4"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.4.4.tgz#eba4f5da9c0dc999de68032d8b4f76173652036b"
@@ -5442,6 +5448,10 @@ source-map@^0.5.3, source-map@^0.5.6, source-map@~0.5.1, source-map@~0.5.3:
   version "0.5.7"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
 
+source-map@^0.6.0:
+  version "0.6.1"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
+
 source-map@~0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.2.0.tgz#dab73fbcfc2ba819b4de03bd6f6eaa48164b3f9d"