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Files whose name ends in `_.js` are not themselves valid Test262 tests
and should not be interpreted as such by test runners.
---
Because the tests in this patch concern declaration *instantiation*,
care has been taken to avoid asserting binding values following
evaluation. Because a given module's dependencies are evaluated prior to
the module itself, this is only observable in modules which import their
own bindings.
A separate patch dedicated to the evaluation of module code asserts the
behavior of bindings following evaluation.
---
For tests that concern the creation of a module namespace object, this
patch relies on the semantics of the `in` operator. The `in` operator
uses the [[HasProperty]] internal method and avoids testing unrelated
semantics concerning binding resolution. Those semantics should be
explicitly asserted with a separate set of tests dedicated to that
purpose.
---
One test case which is notably missing is error resulting from a cycle
due to an `import` declaration (under the current file naming scheme,
such a test might be named `instn-named-err-circular.js`). Due to the
recursive nature of ModuleDeclarationInstantiation, it is not
technically possible for a circular request to be found in step 12.c.i.
Cycles rely on at least 2 `export` declarations, and because these are
resolved *before* imports, any cycle would trigger failure prior to step
12.c.
---
One aspect of *module* resolution that makes ordering observable is the
fact that resolution can fail in two distinct ways (i.e. with a
SyntaxError or with a ReferenceError). This patch includes tests that
leverage this detail in order to assert that modules are resolved in the
correct sequence.
However, from the perspective of the ECMA-262 specification, the
ordering of *export* (e.g. binding) resolution is not observable. This
is due to restrictions on the grammar, where each export is independent.
When *export* resolution fails, it does so with instances of SyntaxError
alone, precluding the above strategy.
So while ModuleDeclarationInstantiation resolves the exports of the
module's dependencies in the following order:
1. "Indirect" exports, e.g.
- `export { x } from './y.js';`
- `export { x as z } from './y.js';`
- `import { x } from './y.js'; export { x };`
2. "Star" imports
- `import * as ns from './y.js';`
3. "Named" (my word) imports
- `import x from './y.js';`
- `import { x } from './y.js';`
- `import { x as z } from './y.js';`
Intentional failures cannot be used to discern resolution ordering.
50 lines
2.3 KiB
JavaScript
50 lines
2.3 KiB
JavaScript
// Copyright (C) 2016 the V8 project authors. All rights reserved.
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// This code is governed by the BSD license found in the LICENSE file.
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/*---
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description: >
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There are no restrictions on the number of cycles during module traversal
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during indirect export resolution, given unique export names.
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esid: sec-moduledeclarationinstantiation
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info: |
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[...]
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9. For each ExportEntry Record e in module.[[IndirectExportEntries]], do
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a. Let resolution be ? module.ResolveExport(e.[[ExportName]], « », « »).
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b. If resolution is null or resolution is "ambiguous", throw a
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SyntaxError exception.
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15.2.1.16.3 ResolveExport( exportName, resolveSet, exportStarSet )
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2. For each Record {[[Module]], [[ExportName]]} r in resolveSet, do:
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a. If module and r.[[Module]] are the same Module Record and
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SameValue(exportName, r.[[ExportName]]) is true, then
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i. Assert: this is a circular import request.
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ii. Return null.
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3. Append the Record {[[Module]]: module, [[ExportName]]: exportName} to resolveSet.
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[...]
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5. For each ExportEntry Record e in module.[[IndirectExportEntries]], do
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a. If SameValue(exportName, e.[[ExportName]]) is true, then
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i. Assert: module imports a specific binding for this export.
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ii. Let importedModule be ? HostResolveImportedModule(module,
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e.[[ModuleRequest]]).
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iii. Let indirectResolution be ?
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importedModule.ResolveExport(e.[[ImportName]], resolveSet,
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exportStarSet).
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iv. If indirectResolution is not null, return indirectResolution.
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flags: [module]
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---*/
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export { a } from './instn-iee-iee-cycle-2_.js';
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export { c as b } from './instn-iee-iee-cycle-2_.js';
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export { e as d } from './instn-iee-iee-cycle-2_.js';
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export { g as f } from './instn-iee-iee-cycle-2_.js';
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export { i as h } from './instn-iee-iee-cycle-2_.js';
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export { k as j } from './instn-iee-iee-cycle-2_.js';
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export { m as l } from './instn-iee-iee-cycle-2_.js';
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export { o as n } from './instn-iee-iee-cycle-2_.js';
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export { q as p } from './instn-iee-iee-cycle-2_.js';
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export { s as r } from './instn-iee-iee-cycle-2_.js';
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export { u as t } from './instn-iee-iee-cycle-2_.js';
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export { w as v } from './instn-iee-iee-cycle-2_.js';
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export { y as x } from './instn-iee-iee-cycle-2_.js';
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export var z;
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