Editorial: Restrict IsValidTimeZoneName case folding to ASCII

[gibson042]

Fixes #1919

[codecov]

Codecov Report

Merging #1920 (0fa7fc3) into main (eb68de2) will increase coverage by 0.02%.
The diff coverage is n/a.

❗ Current head 0fa7fc3 differs from pull request most recent head e3e13b1. Consider uploading reports for the commit e3e13b1 to get more accurate results

@@            Coverage Diff             @@
##             main    #1920      +/-   ##
==========================================
+ Coverage   94.97%   95.00%   +0.02%     
==========================================
  Files          19       19              
  Lines       10990    10990              
  Branches     1750     1600     -150     
==========================================
+ Hits        10438    10441       +3     
+ Misses        535      532       -3     
  Partials       17       17              

Flag	Coverage Δ
test262	79.26% <ø> (ø)
tests	89.90% <ø> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
polyfill/lib/intrinsicclass.mjs	55.40% <0.00%> (+4.05%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update eb68de2...e3e13b1. Read the comment docs.

[ptomato]

This looks like a good change. Although I'm not so confident about my mental model of how things should be divided between ECMA-262 and 402.

@ryzokuken @sffc It would be good to get your review on this as well, for that reason. @FrankYFTang also your perspective as implementor and ECMA-402 contributor.

[sffc]

Seems fine. Procedurally, I think it would be slightly cleaner to make this a standalone normative PR against ECMA-402.

[gibson042]

I think it would be slightly cleaner to make this a standalone normative PR against ECMA-402.

@sffc Done at tc39/ecma402#624, which ended up being editorial. This PR can be simplified after that lands, but will look different based on whether or not a non-ECMA-402 ECMA-262 Temporal implementation is allowed to support a built-in time zone that is absent from the IANA database (which is not allowed of an ECMA-402 implementation).

[ptomato]

tc39/ecma402#624 is merged now, so I think this can be edited somewhat.

[gibson042]

Done.

[FrankYFTang]

Related to this PR- I have hard time w/ tc39/test262#3346 . I am not sure what is the right fix in the spec needed for those tests to pass but right now what I see is the name is not taking TimeZoneUTCOffsetName and the grammar could be changed by #1941 but that is not enough because step 7-a and 7-b of ParseTemporalTimeZoneString will throw. I have not carefully read all details of this PR and I am not sure this PR already has enough change to solve all the remaining issues for that but surely either the calling place in 7a or inside IsValidTimeZoneName need to be changed to solve that.

[ptomato]

Is it the case that anything needs to change in this PR according to the rough consensus we reached in yesterday's champions meeting? For example, do we now need to decouple IsValidTimeZoneName from 402's IsValidTimeZoneName?

[gibson042]

Is it the case that anything needs to change in this PR according to the rough consensus we reached in yesterday's champions meeting? For example, do we now need to decouple IsValidTimeZoneName from 402's IsValidTimeZoneName?

Yes, I think so.

[ptomato]

Is it the case that anything needs to change in this PR according to the rough consensus we reached in yesterday's champions meeting? For example, do we now need to decouple IsValidTimeZoneName from 402's IsValidTimeZoneName?

Yes, I think so.

On second thought, I think it's probably better to put that into its own issue (#1996) so that we don't keep this PR up in the air longer than necessary. I can rebase this today.

[ptomato]

I guess it would be best in that case to remove "Editorial: Add implementation-defined built-in time zone lookup steps" since that takes things more in the direction of unifying 402 and 262 IsValidTimeZone, rather than splitting them. It's a bit difficult to separate but I'll continue working on this tomorrow.

[ptomato]

@gibson042 I've kept the changes that I removed from this PR in a separate branch, https://github.com/tc39/proposal-temporal/tree/gibson042/implementation-defined in case you want to reuse some parts later.