Normative: Fix precision 0 issue in TemporalDurationToString

[FrankYFTang]

See #1859

@ptomato @ljharb @justingrant @ryzokuken @Ms2ger

[codecov]

Codecov Report

Merging #1860 (b433ba2) into main (2959043) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1860   +/-   ##
=======================================
  Coverage   94.78%   94.78%           
=======================================
  Files          19       19           
  Lines       10969    10969           
  Branches     1712     1712           
=======================================
  Hits        10397    10397           
  Misses        557      557           
  Partials       15       15           

Flag	Coverage Δ
test262	81.23% <ø> (ø)
tests	89.42% <ø> (ø)

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

---

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 2959043...b433ba2. Read the comment docs.

[ptomato]

Thanks!

It sounds like there are already test262 tests in the tree that cover this.

I'll convert this to draft and present it at the upcoming TC39 meeting.

[FrankYFTang]

It sounds like there are already test262 tests in the tree that cover this.

Yes, the changed behavior is already tested under

built-ins/Temporal/Duration/prototype/toString/smallestunit-valid-units.js
built-ins/Temporal/Duration/prototype/toString/blank-duration-precision.js
built-ins/Temporal/Duration/prototype/toString/roundingmode-undefined.js

but not aligned with the current spec text unless we take this PR.

[ptomato]

This gained consensus in the October TC39 plenary.