[Bug]: Code transformation regression in jest 28

[hbenl]

Version

28.0.1

Steps to reproduce

1. Clone https://github.com/RecordReplay/devtools
2. Upgrade jest and babel-jest to 28.0.1 and add jest-environment-jsdom
3. npm run test

Expected behavior

The tests pass as they did with jest 27.

Actual behavior

I get several failures like this one:

    ● Invalid return value:
      Code transformer's `process` method must return an object containing `code` key 
      with processed string. If `processAsync` method is implemented it must return 
      a Promise resolving to an object containing `code` key with processed string.
      Code Transformation Documentation:
      https://jestjs.io/docs/code-transformation
    

       8 | const bundles = {
       9 |   "devtools/client/locales/toolbox.properties": parse(
    > 10 |     require("devtools/client/locales/en-us/toolbox.properties").default
         |     ^
      11 |   ),
      12 |   "devtools/client/locales/debugger.properties": parse(
      13 |     require("devtools/client/locales/en-us/debugger.properties").default

      at ScriptTransformer._buildTransformResult (node_modules/@jest/transform/build/ScriptTransformer.js:504:15)
      at ScriptTransformer.transformSource (node_modules/@jest/transform/build/ScriptTransformer.js:623:17)
      at ScriptTransformer._transformAndBuildScript (node_modules/@jest/transform/build/ScriptTransformer.js:760:40)
      at ScriptTransformer.transform (node_modules/@jest/transform/build/ScriptTransformer.js:817:19)
      at Object.require (src/shims/l10n.js:10:5)

Additional context

No response

Environment

System:
    OS: Linux 5.13 Ubuntu 20.04.4 LTS (Focal Fossa)
    CPU: (12) x64 AMD Ryzen 5 1600 Six-Core Processor
  Binaries:
    Node: 16.14.2 - /usr/bin/node
    Yarn: 1.22.18 - ~/replay/devtools/node_modules/.bin/yarn
    npm: 8.5.0 - /usr/bin/npm
  npmPackages:
    jest: ^28.0.1 => 28.0.1

[mrazauskas]

On surface it looks like your transformer’s process method is returning a string instead of an object. See Migration Guide.

Hard to say more without a minimal reproduction. The link repo does not install for me. Cloning it and running npm i throws a bunch of: "Conflicting peer dependency", "Could not resolve dependency", "Fix the upstream dependency conflict, or retry".

[mrazauskas]

Might be enough to change one line inside /test/jest/jest-text-transformer.js:

  process(src) {
    // console.log("Processing file: ", src);
    const escapedSrc = src.replace(/`/g, "\\`").replace(/\$(?=\{.*?\})/g, "\\$");


-   return `module.exports.default = \`${escapedSrc}\``;
+   return { code: `module.exports.default = \`${escapedSrc}\`` };
  },

[SimenB]

That's correct 🙂 It also works in older versions of jest, so safe to land that change while still remaining on whatever jest version you have already

[SimenB]

@mrazauskas perhaps we could include the path to the transformer that returns the wrong structure?

We could also link to the upgrade guide in the error message

[mrazauskas]

Right. There are few more places where the link would be useful. I will do this.

[hbenl]

Might be enough to change one line [...]

Yes, it works now. Thanks a lot for the help!

perhaps we could include the path to the transformer that returns the wrong structure?

That sounds like a good idea - obviously I had not realized that it was our own transformer (as opposed to some jest internals) that needed to be changed.

[SimenB]

https://github.com/facebook/jest/releases/tag/v28.0.3

[github-actions]

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