lib: map Latin1 labels to iso-8859-1 instead of Windows-1252

[lytovka]

Fixes: #56542

This PR updates all Latin1 labels to point to the iso-8859-1 encoding instead of Windows-1252. The iso-8859-1 encoding will now use the decodeLatin1 fast path when calling the decode method. The Windows-1252 encoding will not trigger the decodeLatin1 fast path; instead, it will follow the standard path for obtaining the converter from the simdutf library.

A new test file has been added to verify the decoded Unicode values of bytes 0x7F-0x9F when the Windows-1252 encoding is selected.

NB: Fixing Latin1 label mappings will cause unexpected behavior if TextDecoder is called with any Latin1 label and attempts to decode bytes in the 0x80-0x9F range, since decoding for any of these labels will now follow the iso-8859-1 encoding.

Refs:

• ISO-8859-1 code page layout: https://en.wikipedia.org/wiki/ISO/IEC_8859-1#Code_page_layout
• Windows-1252 code page layout: https://en.wikipedia.org/wiki/Windows-1252#Codepage_layout

[nodejs-github-bot]

Review requested:

• @nodejs/web-standards

[jasnell]

I do have some slight concerns over whether this may be considered a breaking change. My preference would be to handle it as a bug fix, however. I'd like some feedback from @nodejs/tsc

[lytovka]

I do have some slight concerns over whether this may be considered a breaking change. My preference would be to handle it as a bug fix, however. I'd like some feedback from @nodejs/tsc

I had similar thoughts. I've updated the PR description with a note explaining why this could be considered a breaking change:

NB: Fixing Latin1 label mappings will cause unexpected behavior if TextDecoder is called with any Latin1 label and attempts to decode bytes in the 0x80-0x9F range, since decoding for any of these labels will now follow the iso-8859-1 encoding.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.10%. Comparing base (4c65776) to head (43fbb04).
Report is 85 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #58890      +/-   ##
==========================================
- Coverage   90.10%   90.10%   -0.01%     
==========================================
  Files         640      640              
  Lines      188431   188427       -4     
  Branches    36956    36959       +3     
==========================================
- Hits       169783   169776       -7     
+ Misses      11362    11359       -3     
- Partials     7286     7292       +6     

Files with missing lines	Coverage Δ
lib/internal/encoding.js	98.87% <100.00%> (-0.65%)	⬇️

... and 46 files with indirect coverage changes

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[targos]

I think we should land as a bug fix.

[lytovka]

Hi all! Just to confirm - aside from addressing the linting errors (43fbb04), is there anything else you'd like me to do before this can land? Thanks!

[lytovka]

@jasnell @targos @nodejs/tsc – bumping this up, let me know if there's anything missing. Thank you in advance!

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/67956/