Add decorator tests#5048
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Add behavioral tests for the TC39 decorators proposal, covering: - Decorator context object (kind, name, access, static, private) - Return value handling for class, method, getter, setter, field, and accessor decorators - Decorator ordering (application order, initialization phases) - Class decorator rebinding and proxy/subclass returns - Field and accessor initializer `this` binding - Invalid return value error cases - Computed member expression syntax errors Tests use test262's template/case generation system to cover all combinations of class declarations/expressions, public/private, instance/static, and standard/with-init variants. Based on tc39#4103. Co-Authored-By: Kristen Maevyn <kris@bitski.com> Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- accessor-deco-returns-set: "getter" -> "setter" - context-access-set: "`get`" -> "`set`" - context-kind-accessor: "a method" -> "an accessor" - context-kind-class: "a method" -> "a class" - context-kind-getter: '"method"' -> '"getter"', "a method" -> "a getter" - context-kind-setter: "a method" -> "a setter" - context-static-true: "false for instance" -> "true for static" - context-private-true/false: swap file contents to match filenames (true.case now tests private elements, false.case tests public) Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The template was applying the decorator to a private method inside the class expression instead of to the class expression itself. This caused class decorator error cases (e.g. class-deco-invalid-return-arrow) to test method decorator behavior when expanded through this template. Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
prod-FieldExpression -> prod-ClassExpression Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Copy-paste artifact from class-deco-returns-subclass.case. Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
All 8 generator method templates had identical path: values to standard method templates (e.g. method/public/instance/). Generated tests from generator templates would silently overwrite standard method tests. Add generator/ subdirectory to all paths so generated tests land in method/generator/public/instance/ etc., matching the convention used by async method templates (method/async/). Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
These are standard (non-error) getter templates but their path: values included an error/ segment, causing generated tests to land in the wrong directory (getter/error/ instead of getter/). Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Generator and async method templates had the same name: values as standard method templates, making generated test descriptions ambiguous. Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add 8 templates for async generator methods (async * element()) covering all public/private, instance/static, declaration/expression combinations. Add async-generator-specific cases for return value replacement and undefined return behavior, testing that the decorated value produces an async iterator. Update context-kind-method and context-access-get cases to include the new async-generator template set. Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Decorators cannot be applied to class constructors per the ClassElement grammar. Verify this is a SyntaxError for both class declarations and class expressions. Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- Non-callable argument: addInitializer(123) throws TypeError during class evaluation. Uses the error template to cover all element types (methods, fields, getters, setters, accessors, class). - After decoration: saving context and calling addInitializer after class evaluation completes throws TypeError. Standalone tests since the class itself evaluates successfully. Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Would maintainers prefer this be split into smaller PRs? |
Contributor
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@bennypowers Thanks very much for this. Smaller PRs would be better for reviews. But note that decorators are on the agenda in next week's TC39 meeting (https://github.com/tc39/agendas/blob/main/2026/05.md) so please wait and see what comes out of that discussion before doing any substantial further work on this PR, in case it would be wasted. |
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Add behavioral tests for the TC39 decorators proposal, covering:
kind,name,access,static,private)thisbinding@decorators[0])addInitializererror cases (non-callable argument, call after decoration)Tests use test262's template/case generation system to cover all
combinations of class declarations/expressions, public/private,
instance/static, and standard/with-init variants.
Based on #4103 by @pzuraq, with fixes for:
error/path segmentcontext-private-true/falsefilenamesesidin class expression templateValidated test behavior against ecma262 PR #2417
and V8's decorator implementation.
Co-Authored-By: Kristen Maevyn kris@bitski.com