Typescript watcher cannot recover

[karolis-sh]

• Rollup Plugin Name: @rollup/plugin-typescript
• Rollup Plugin Version: 4.0.0
• Rollup Version: 2.0.3
• Operating System (or Browser): mac
• Node Version: 10.15.0

How Do We Reproduce?

Running rollup in watch mode with typescript plugin if the typescript code is invalid the watcher breaks and exits with exit code 1. This make it impossible to re-build the code on code changes - you need to re-start the command every time.

1. Start with a simple ts file:

export default (a: number, b: number): number => {
  return a + b;
};

2. Start the watcher rollup -c --watch
3. Comment out out some code (making it invalid syntax) and save the file:

export default (a: number, b: number): number => {
  return a + b;
// };

4. The watcher breaks completely:

{ Error: @rollup/plugin-typescript TS1005: '}' expected.
    at error (/THE_REPRO/node_modules/rollup/dist/shared/rollup.js:10120:30)
    at throwPluginError (/THE_REPRO/node_modules/rollup/dist/shared/rollup.js:16242:12)
    at Object.error (/THE_REPRO/node_modules/rollup/dist/shared/rollup.js:17226:24)
    at emitDiagnostic (/THE_REPRO/node_modules/@rollup/plugin-typescript/dist/index.js:412:17)
    at reportDiagnostics (/THE_REPRO/node_modules/@rollup/plugin-typescript/dist/index.js:420:9)
    at Array.forEach (<anonymous>)
    at emitFilesAndReportErrors (/THE_REPRO/node_modules/typescript/lib/typescript.js:102879:21)
    at Object.result.afterProgramCreate (/THE_REPRO/node_modules/typescript/lib/typescript.js:103054:13)
    at Object.afterProgramCreate (/THE_REPRO/node_modules/@rollup/plugin-typescript/dist/index.js:441:29)
    at synchronizeProgram (/THE_REPRO/node_modules/typescript/lib/typescript.js:103300:22)
  pluginCode: 'TS1005',
  loc:
   { column: 1,
     line: 4,
     file:
      '/THE_REPRO/packages/app/src/test.ts' },
  frame:
   '\n\u001b[7m4\u001b[0m \n\u001b[7m \u001b[0m \u001b[91m\u001b[0m\n\n  \u001b[96msrc/test.ts\u001b[0m:\u001b[93m1\u001b[0m:\u001b[93m50\u001b[0m\n    \u001b[7m1\u001b[0m export default (a: number, b: number): number => {\n    \u001b[7m \u001b[0m \u001b[96m                                                 ~\u001b[0m\n    The parser expected to find a \'}\' to match the \'{\' token here.\n',
  code: 'PLUGIN_ERROR',
  plugin: 'typescript' }
error Command failed with exit code 1.

rollup.config.js:

import typescript from '@rollup/plugin-typescript';
import babel from 'rollup-plugin-babel';
import peerDepsExternal from 'rollup-plugin-peer-deps-external';
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';
import postcss from 'rollup-plugin-postcss';
import { terser } from 'rollup-plugin-terser';
import autoprefixer from 'autoprefixer';
import cssnano from 'cssnano';
import reactSvg from 'rollup-plugin-react-svg';

import pkg from './package.json';

const isProd = process.env.NODE_ENV === 'production';

export default {
  input: 'src/index.js',
  output: { format: 'cjs', file: pkg.main, sourcemap: true },
  plugins: [
    typescript(),
    babel({ exclude: 'node_modules/**' }),
    resolve(),
    commonjs(),
    peerDepsExternal({ includeDependencies: true }),
    postcss({ plugins: isProd ? [autoprefixer, cssnano] : [] }),
    reactSvg({ svgo: { plugins: [{ removeViewBox: false }] } }),
    isProd && terser({ compress: true, mangle: true }),
  ].filter(Boolean),
};

Expected Behavior

The watcher shouldn't exit with exit code 1, it should wait for further code changes and try to recompile modified source.

Actual Behavior

Watcher breaks and exits with exit code 1.

[shellscape]

Thanks for opening an issue. Citing the issue template:

Issues without minimal reproductions will be closed! Please provide one by:

1. Using the REPL.it plugin reproduction template at https://repl.it/@rollup/rollup-plugin-repro
2. Provide a minimal repository link (Read https://git.io/fNzHA for instructions).
   These may take more time to triage than the other options.
3. Using the REPL at https://rollupjs.org/repl/

Please add a reproduction and we'll be happy to triage further.

[NotWoods]

You should also use the noEmitOnError option to only warn, rather than error.