feat(patterns): For containerHasSplit(copyArray, ...), scan from the start

[gibson042]

Ref #3065 (comment)

Description

Avoids returning result arrays with elements in reversed order.

Security Considerations

None known.

Scaling Considerations

n/a

Documentation Considerations

Ignored.

Testing Considerations

Updated tests from #3065.

Compatibility Considerations

This is a behavior change, but I don't think containerHasSplit even has use yet, nor do I expect reliance upon the counterintuitive behavior.

Upgrade Considerations

I think this fix falls below the level of inclusion in NEWS.md, but could be persuaded out of that position.

[erights]

Be aware that a Set amount value necessarily lists its elements in descending order, just like the payload of a CopySet amount value. See

https://github.com/Agoric/agoric-sdk/blob/b5638874e8aa65b633fd348139fa4980f15670ff/packages/ERTP/src/mathHelpers/setMathHelpers.js#L26

 list = coerceToElements(list);

and

endo/packages/patterns/src/keys/copySet.js

Line 94 in b41c080

export const coerceToElements = elementsList => {

How does that affect the desirability or relevance of this change? (Not rhetorical. I genuinely don't know yet.)

[changeset-bot]

🦋 Changeset detected

Latest commit: a58e436

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@endo/patterns	Minor
@endo/cli	Patch
@endo/daemon	Patch
@endo/exo	Patch

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[gibson042]

Be aware that a Set amount value necessarily lists its elements in descending order, just like the payload of a CopySet amount value. See

https://github.com/Agoric/agoric-sdk/blob/b5638874e8aa65b633fd348139fa4980f15670ff/packages/ERTP/src/mathHelpers/setMathHelpers.js#L26

 list = coerceToElements(list);

and

endo/packages/patterns/src/keys/copySet.js

Line 94 in b41c080

export const coerceToElements = elementsList => {

How does that affect the desirability or relevance of this change? (Not rhetorical. I genuinely don't know yet.)

I'm actually not clear on what this is even asking, since containerHasSplit requires its input specimen to be a copyArray, copySet, or copyBag.

[erights]

I'm actually not clear on what this is even asking, since containerHasSplit requires its input specimen to be a copyArray, copySet, or copyBag.

I no longer think it is relevant, so nevermind.

[erights]

Suggested change

	outResults,
	-1,
	) &&

[erights]

or am I missing something?

[gibson042]

This is a call to pairsHasSplit, which is analogous to confirmElementsHasSplit but lacks a direction parameter because it's only applicable to CopyBag payloads and so always iterates by descending array index. There's coverage in packages/patterns/test/containerHasSplit.test.js , but I've just updated src/ comments as well.

[erights]

LGTM, thanks!