Ask for Feedback: Make `JSObject` / `JSFunction` calls be `throws`
Nobody has claimed this yet.
Assessment
- Difficulty
- 5/5
- Estimated time
- Over a week
- Newbie friendliness
- 25/100
- Issue type
- Feature
- Clarity
- Needs clarification
- Activity status
- Stale
- Tech stack
- javascript, swift, wasm
- Domain
- api
Research direction
The issue names JSObject and JSFunction as the affected APIs but gives no file or test entry point. Review their call implementations and existing .throws/.throwing behavior, then measure the performance trade-off and define tests for throwing and nonthrowing calls before deciding the breaking API change.
Written by the indexing model from the issue text.
Description
Every dynamic JS function calls can throw an exception, but the current JSObject and JSFunction are non-throws by default.
They can be throws by .throws or .throwing but it's still opt-in.
For example, if an exception is thrown during a JS function call but the call site in Swift side is not throws, the control unwinding wasm call frames without executing function epilogues even if there is do { } catch {} clause in Swift. And also in that case, defer blocks won't be called.
This behavior is quite tricky and unwinding wasm call frames without executing function epilogues can lead to memory and resource leak.
I'm going to introduce an API breaking change to make JSObject / JSFunction calls be throws in the next next release to improve the situation.
This change has a performance tradeoff as throws variants are typically a little bit slower than non-throwing variants. We should measure the amount of the penalty but it shouldn't be a big deal. We can make non throwing calls as an opt-in feature so that those who want best performance can satisfy their needs.
// Before
let foo = JSObject.global.document.getElementById!("foo")
let foo = try JSObject.global.document.throwing.getElementById!("foo")
// After
let foo = try JSObject.global.document.getElementById!("foo")
let foo = JSObject.global.document.nonthrowing.getElementById!("foo")
Let me know here if you have a strong objection 🙏 Thanks.
- Dominant language
- Swift
- Stars
- 986
- Forks
- 76
- Avg merge
- 21h 11m
- Merged PRs (30d)
- 4
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
More from swiftwasm/JavaScriptKit
-
Difficulty 3/5 1-2 days Newbie friendliness 55/100
swiftwasm/JavaScriptKit#793 ·
-
swiftwasm/JavaScriptKit#785 · 1 assignee ·
-
[SwiftBuild] Preserve duplicate archive members when SwiftBuild expands static archives for linking Open
Difficulty 4/5 3-5 days Newbie friendliness 48/100
swiftwasm/JavaScriptKit#781 · 3 comments ·
-
Difficulty 4/5 3-5 days Newbie friendliness 25/100
swiftwasm/JavaScriptKit#773 ·
-
swiftwasm/JavaScriptKit#767 · 1 assignee ·
All issues in swiftwasm/JavaScriptKit
Similar issues
-
Difficulty 2/5 1-3 hours Newbie friendliness 88/100
manaflow-ai/cmux#13763 ·
-
type: feature request
Difficulty 2/5 1-3 hours Newbie friendliness 82/100
googleapis/google-cloud-swift#1036 · 1 comment ·
-
Difficulty 1/5 Under an hour Newbie friendliness 78/100
wultra/mtoken-sdk-ios#253 ·
-
area:dictation documentation P2
Difficulty 2/5 1-3 hours Newbie friendliness 78/100
uttrflow/uttrflow-swift#1180 ·
-
Difficulty 2/5 1-3 hours Newbie friendliness 78/100