v8 coverage crashes with type-only files

🐛 Bug Report

With coverageProvider: 'v8' and coverage enabled, Jest crashes with imported but non-elided type-only modules.

To Reproduce

Steps to reproduce the behavior:

• jest.config.mjs:

  export default {
    collectCoverage: true,
    coverageProvider: 'v8',
    rootDir: 'src'
  };
  

• babel.config.json

  {
    "presets": [
      "@babel/typescript"
    ]
  }
  

• src/types.ts:

  export interface obj {}
  

• src/mytest.test.ts:

  import * as types from './types';
  
  test('1+1=2', () => {
    console.log(types);
    expect(1 + 1).toBe(2);
  });
  

• Run npx jest

  PASS  src2/mytest.test.ts
    √ 1+1=2 (16 ms)
  
    console.log
      { default: {} }
  
        at Object.<anonymous> (mytest.test.ts:4:11)
  
  TypeError: Cannot read property 'replace' of undefined
      at V8ToIstanbul._resolveSource (D:\repo\node_modules\v8-to-istanbul\lib\v8-to-istanbul.js:86:29)
      at V8ToIstanbul.load (D:\repo\node_modules\v8-to-istanbul\lib\v8-to-istanbul.js:57:26)
      at D:\repo\node_modules\@jest\reporters\build\CoverageReporter.js:624:27
      at Array.map (<anonymous>)
      at CoverageReporter._getCoverageResult (D:\repo\node_modules\@jest\reporters\build\CoverageReporter.js:587:32)
      at CoverageReporter.onRunComplete (D:\repo\node_modules\@jest\reporters\build\CoverageReporter.js:231:45)
      at ReporterDispatcher.onRunComplete (D:\repo\node_modules\@jest\core\build\ReporterDispatcher.js:88:9)
      at TestScheduler.scheduleTests (D:\repo\node_modules\@jest\core\build\TestScheduler.js:350:5)
      at runJest (D:\repo\node_modules\@jest\core\build\runJest.js:376:19)
      at _run10000 (D:\repo\node_modules\@jest\core\build\cli\index.js:416:7)
  

Expected behavior

Jest doesn’t crash, and coverage works.

Link to repl or repo (highly encouraged)

envinfo

  System:
    OS: Windows 10 10.0.19042
    CPU: (64) x64 AMD Ryzen Threadripper 3970X 32-Core Processor
  Binaries:
    Node: 15.2.0 - C:\Program Files\nodejs\node.EXE
    npm: 7.0.8 - C:\Program Files\nodejs\npm.CMD
  npmPackages:
    jest: ^26.6.3 => 26.6.3

[bcoe]

Just merged @viceice’s patch 👌 sorry for the nuisance.

[SimenB]

This is what we pass

{
  originalSource: 'export interface obj {}\n\n',
  source: '"use strict";\n' +
    '//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IiIsInNvdXJjZXNDb250ZW50IjpbXX0=',
  sourceMap: {
    sourcemap: {
      version: 3,
      sources: [],
      names: [],
      mappings: '',
      sourcesContent: []
    }
  }
}

Seems like a bug in v8-to-istanbul to me. We pass a valid sourcemap - it’s just empty