Normative: Add `using` and `await using` Declarations, SuppressedError, DisposableStack, and AsyncDisposableStack by rbuckton · Pull Request #3000 · tc39/ecma262

rbuckton · 2023-01-23T22:42:45Z

This PR contains the Stage 3 specification text for Explicit Resource Management.

rbuckton · 2023-01-24T00:04:30Z

I'm not quite sure how to address the remaining esmeta issues.

jmdyck · 2023-01-24T03:05:35Z

Rather than suggest changes here, I've made a PR against this PR's branch: rbuckton#2

rbuckton · 2023-01-25T21:18:34Z

This last commit adds a few UpdateEmpty calls that aren't strictly necessary, but esmeta doesn't quite understand what's happening without it. I also had to switch AO parameters typed : a function object to : an ECMAScript language value since IsCallable doesn't seem to act as a type guard.

bakkot · 2023-01-25T22:56:34Z

@rbuckton Sorry about that - esmeta is still a little imprecise. You should feel free to write the spec text you want and not worry about esmeta's errors, and we can update esmeta or the ignore file.

rbuckton · 2023-01-26T16:38:45Z

@rbuckton Sorry about that - esmeta is still a little imprecise. You should feel free to write the spec text you want and not worry about esmeta's errors, and we can update esmeta or the ignore file.

I replaced the UpdateEmpty calls with a few asserts that seem to be accurate. For example, in ForIn/OfBodyEvaluation, if status is abrupt going in to DisposeResources, it should still be abrupt on the way out. Likewise, ForBodyEvaluation won't return a normal completion for empty, so DisposeResources shouldn't produce one either.

rbuckton · 2023-01-27T15:28:28Z

Please note, I've created rbuckton#3 as a separate PR against this one containing the additional specification changes that would be necessary to support https://github.com/tc39/proposal-async-explicit-resource-management, should it advance to Stage 3.

rbuckton · 2023-03-22T16:12:16Z

I found an issue with the change in e4f2d05 to use an EE to restrict binding patterns, in that it results in an ambiguous parse of using[x] before the EE can be applied, which was not intended.

I've filed tc39/proposal-explicit-resource-management#152 against the proposal spec, and will update this PR in due time.

rbuckton · 2023-03-22T18:20:23Z

I found an issue with the change in e4f2d05 to use an EE to restrict binding patterns, in that it results in an ambiguous parse of using[x] before the EE can be applied, which was not intended.

I've filed tc39/proposal-explicit-resource-management#152 against the proposal spec, and will update this PR in due time.

tc39/proposal-explicit-resource-management#152 has merged, and I've amended this PR to match as part of 3044fd9.

rbuckton · 2024-03-22T18:18:10Z

This now includes the await using declaration and AsyncDisposableStack, per prior consensus (incl. the March 2023 plenary).

rbuckton · 2024-03-22T18:22:26Z

Note to implementers: There is a typo in GetDisposeMethod that will be addressed by tc39/proposal-explicit-resource-management#217. The typo was introduced as part of a normative change that reached consensus in July 2023, but fixing it is also a potentially a normative change and may require additional consensus.

rbuckton · 2024-03-22T18:44:26Z

This is also missing the consensus change to use await using as the syntactic head for the asynchronous form of the using declaration. That will be up shortly.

rbuckton · 2024-03-22T20:17:19Z

25f1bc4 applies changes from the following PRs which previously achieved consensus in March 2023 and July 2023:

ljharb · 2026-06-02T21:59:27Z

This needs to be rebased before it can be merged, and it's not a trivial one.

rbuckton · 2026-06-14T14:44:57Z

Squashed and rebased to simplify history and make things easier.

jmdyck

Just some rebase-related updates.

rbuckton · 2026-06-17T17:34:22Z

Just some rebase-related updates.

Updated. Can you take another look?

jmdyck · 2026-06-18T13:24:29Z

Looks like that resolves all my nits.

rbuckton · 2026-06-18T22:01:52Z

Looks like that resolves all my nits.

Mind approving then? It shows you as having open requested changes.

resolved

@jmdyck

…r, DisposableStack, and AsyncDisposableStack (tc39#3000) * Spec text for proposal-explicit-resource-management * Fix lint errors * Run formatter * Fix signature for DisposeResources * Fixes for some esmeta warnings * Fixes for some esmeta warnings * Add missing ReturnIfAbrupt in DisposableStack.prototype.use * More ecmarkup signature fixes * Change DisposeResources signature to return completion record * Order sections by property name * Syntax of types * id of AO clause doesn't need to include param names * Avoid the use of `Type()` * Use preamble conventions from PR tc39#2592 * Interface names are put in `<i>` rather than `<em>` * A 'Slots' table should have a 'Type' column * Add 'UsingDeclaration' to Annex A * misc minor fixes * add description suggestion from @jmdyck * Add DisposeCapabilityRecord from tc39/proposal-explicit-resource-management#144 * Wrap UpdateEmpty calls in calls to Completion * Run formatter * Run formatter again * Fix formatting and capitalization * Clean up DisposeResources signature, replace UpdateEmpty with assertions * Add 'either' in front of 'null or undefined' * Use CreateBuiltinFunction * Address additional editor feedback (from async PR) * Move BindingPattern restriction for 'using' to an early error * Fix typo in using declaration early errors * Fix typos * run formatter * Remove InstallErrorCause from SuppressedError, per 2023-jan consensus * Spec text for proposal-async-explicit-resource-management * Run formatter * Add 'either' in front of 'null or undefined' * Address editor feedback * Address additional editor feedback * Switch back to a production parameter, update ASI note * Remove 'await' restriction per March 2023 consensus. See tc39/proposal-explicit-resource-management#153 * Adopt consensus changes from tc39/proposal-explicit-resource-management#178 * Adopt consensus changes from tc39/proposal-explicit-resource-management#180 * Adopt typo fix from tc39/proposal-explicit-resource-management#217 * Fix typos and add temporary PR note * Remove temporary PR note * Remaining consensus updates from proposal repo * Add missing undefined check in GetDisposeMethod * Fix DisposeCapability leak * fix formatting * Switch to empty list * Update text of NOTE * Add PromiseCapability wrapper around sync dispose in an `await using` * Fix missing lookahead restriction * Remove superfluous ClassBody restriction * Add entries to esmeta-ignore * Reduce unnecessary Awaits for nullish values in blocks containing `await using` * Add missing 'constructor' definitions * Disallow using/await using in a switch case/default clause * Fix formatting * PR feedback * minor fixes * Switch from @@ to % in a few more places * Update esmeta-ignore.json * Update asyncDispose to be an async method * avoid threading kind through all the InitializeBinding machinery * rename _kind_ to _declarationKind_ in ForIn/OfBodyEvaluation since there's already _iterationKind_ and _lhsKind_ * move _declarationKind_ into the branch where that makes sense otherwise we're calling IsUsingDeclaration/IsAwaitUsingDeclaration on potentially an assignment target or var declaration, which they aren't defined over. * move it back * PR Feedback * Some missing changes pulled from #11 * Fix some remaining suggestions from #7 * Switch to `<em>` where appropriate * PR feedback * Don't overwrite completion parameter in DisposeResources * The spec usually uses lower-case for ids. * Drop 'variants' attribute * Changes to Annex A to make it parallel to main-body grammar * Add subclauses to "Constructor Properties of The Global Object" * Need to define ForDeclarationBindingInitialization for ForDeclaration * Remove unreachable SDO rules * Remove more unreachable SDO rules * Remove unnecessary steps in CreateDisposableResource * Add explicit return to algorithm * EvaluateClassStaticBlockBody: add an Assert * Remove 'kind' description from InitializeBinding * CaseBlock can't have resources, so just assert * Restore missing NOTE and fix indentation * ContainsUsing and HasUnterminatedUsingDeclaration are identical * Rename V to value and O to obj * Use list shorthand for NewDisposeCapability * Rely on NOTE rather than overwriting [[DisposableResourceStack]] * Add type to clauses and use 'this method' * Merge branch 'main' into explicit-resource-management * Revert changes to esmeta-ignore.json * PR fix type and function/method usage * Additional editorial feedback * Refactor out DisposeCapability * Fix internal slot typo * Remove unused Dispose AO * Editorial feedback * Remove excess argument to 'return' method * Restore 'then' in assertion * Restore old ids * SuppressedError.prototype description * Revert 'this function'->'this method' * 'property'->'properties' in (Async)Disposable interface desc * Other editorial feedback * no list for mutually exclusive states * Align aliases with tc39#3873 * PR feedback * Symbol description wording * Merge pull request #17 from rbuckton/excess-iter-return-argument Remove excess argument to 'return' method * Revert function->method changes

rbuckton force-pushed the explicit-resource-management branch from b7b82d5 to 17e0bc0 Compare January 23, 2023 23:33

ljharb marked this pull request as draft January 25, 2023 22:30

jmdyck reviewed Jan 26, 2023

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