[Bug]: Jest uses the wrong Prettier parser for Flow files, leading to unparsable code

[captbaritone]

Version

28.1.1 (latest)

Steps to reproduce

git clone git@github.com:captbaritone/jest-flow-prettier-issue.git
cd jest-flow-prettier-issue
yarn
yarn repro # jest -u

Expected behavior

The snapshot updates and the rest of the file is left untouched.

Actual behavior

The snapshot updates and line 3 of test.js is updated to remove the quotes. Now Flow can't parse that file.

Additional context

When updating inline snapshots Jest applies Prettier. Unfortunatly with Flow files, Jest disregards the parser defined in the user's Pretteir config and instead uses an infered one for that file.

In the case of Flow files, Jest seems to pick incorrectly, and instead uses babel.

This leads prettier to think it's okay to remove quotes around numeric object keys.

Note that Prettier never unquotes numeric property names in Angular expressions, TypeScript, and Flow because the distinction between string and numeric keys is significant in these languages

-- Prettier Docs

The result is that Jest writes back a snapshot file which Prettier cannot parse, and so even subsequent Prettier runs cannot restore the file to a parseable state.

The only recourse is to manually update all numeric keys in the test file (and to be very careful not to ever update the inline snapshot automatically ever again).

The bug is caused on this line of jest-snapshot where the inferred parser is preferred over one explicitly defined in the config. Note how Prettier itself prefers the explicit parser defined in the config over inferring the parser code pointer.

Environment

System:
    OS: macOS 12.2.1
    CPU: (10) arm64 Apple M1 Pro
  Binaries:
    Node: 17.3.0 - ~/.nvm/versions/node/v17.3.0/bin/node
    Yarn: 1.22.17 - ~/.nvm/versions/node/v17.3.0/bin/yarn
    npm: 8.3.0 - ~/.nvm/versions/node/v17.3.0/bin/npm
  npmPackages:
    jest: ^28.1.1 => 28.1.1

[captbaritone]

Example of real world file where this was discovered: https://github.com/facebook/relay/blob/464c4d1866d17d459513e7177dfcc18af4fb0d15/packages/relay-runtime/store/__tests__/ClientEdgeToClientObject-test.js#L125-L151

[SimenB]

Any idea how to fix this?

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[JVBorges]

Hi, can I take a look at this issue?

[github-actions]

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