fix(jest-snapshot): always run prettier format a second time

[G-Rath]

Summary

When writing inline snapshots, the custom prettier parser that handles indenting the snapshots is only called if there's a formatting difference between the original code vs with the new snapshot, which will only happen if the file needs to be formatted with prettier anyway.

This means if you already have code that is correctly formatted in prettier's eyes, we get a regression of #9477:

This wasn't caught by the test suite because (among other things), writeFiles calls dedent on all the file content its given which strips out all trailing and leading blank lines; this means that all files written by the suite using this method are considered not correctly formatted by prettier because it requires files have a trailing blank newline.

I've reproduced this by crafting a test whose file contents is considered correctly formatted, including with a trailing newline by using \\n to have dedent preserve that specific new line, and have fixed it by removing the formatting check - so now prettier.format is always called a second time to apply the snapshot parser/indenter.

Resolves #11459

Test plan

I've added a new test.

[codecov-commenter]

Codecov Report

Merging #11560 (cc34849) into main (341843f) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main   #11560      +/-   ##
==========================================
- Coverage   68.73%   68.73%   -0.01%     
==========================================
  Files         322      322              
  Lines       16580    16577       -3     
  Branches     4784     4783       -1     
==========================================
- Hits        11397    11394       -3     
  Misses       5150     5150              
  Partials       33       33              

Impacted Files	Coverage Δ
packages/jest-snapshot/src/InlineSnapshots.ts	90.60% <100.00%> (-0.19%)	⬇️

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[G-Rath]

@SimenB I managed to get it reproduced :D

I've restored the condition to confirm that the test fails on CI against the snapshot (which contains the correctly indented output) - will drop that commit after & restructure the code to call prettier twice.

I originally tried to do this using an object, but for some reason the sourceFileWithSnapshots kept having { a: '' } (instead of {a: ''}) for some reason, which would cause the conditional path to trigger. I couldn't shake that no matter what I tried, so there might technically be another bug in there but I think it might not actually be an issue - I was able to reproduce using arrays so for this PR it's now a non-issue 🤷

[G-Rath]

/Users/runner/work/jest/jest/packages/jest-repl/src/__tests__/runtime_cli.test.js

  ● Runtime CLI › throws script errors

    expect(received).toMatch(expected)

    Expected substring: "Error: throwing"
    Received string:    "Error: Cannot parse /Users/runner/work/jest/jest/e2e/console-log-output-when-run-in-band/package.json as JSON: ENOENT: no such file or directory, open '/Users/runner/work/jest/jest/e2e/console-log-output-when-run-in-band/package.json'
        at Object.worker (/Users/runner/work/jest/jest/packages/jest-haste-map/build/worker.js:146:13)
        at execFunction (/Users/runner/work/jest/jest/packages/jest-worker/build/workers/processChild.js:145:17)
        at execHelper (/Users/runner/work/jest/jest/packages/jest-worker/build/workers/processChild.js:124:5)
        at execMethod (/Users/runner/work/jest/jest/packages/jest-worker/build/workers/processChild.js:128:5)
        at process.messageListener (/Users/runner/work/jest/jest/packages/jest-worker/build/workers/processChild.js:46:7)
        at process.emit (events.js:376:20)
        at emit (internal/child_process.js:910:12)
        at processTicksAndRejections (internal/process/task_queues.js:83:21)"

      at Object.toMatch (packages/jest-repl/src/__tests__/runtime_cli.test.js:51:52)

😞 tho I don't think thats the result of my change.

[G-Rath]

@SimenB any chance of getting a quick review? 😅

[nfarina]

Would love this merged so I can upgrade to Jest 27! Starting to use inline snapshots extensively and the lack of indentation is a deal breaker.

[G-Rath]

@SimenB would be great if we could land this 🙂

[SimenB]

Thanks!

And sorry about the delay

[github-actions]

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