hbs-parser: register block-param scope for as |x|#189
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NullVoxPopuli merged 2 commits intoember-tooling:mainfrom Apr 16, 2026
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hbs-parser: register block-param scope for as |x|#189NullVoxPopuli merged 2 commits intoember-tooling:mainfrom
as |x|#189NullVoxPopuli merged 2 commits intoember-tooling:mainfrom
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The HBS parser previously analyzed an empty stub Program, so block
params from `<Foo as |x|>` and `{{#let ... as |x|}}` were never
registered in any scope. Downstream rules that walk scope to resolve
block-param references (or check whether an angle-bracket tag is a
local variable, e.g. template-no-block-params-for-html-elements in
eslint-plugin-ember) had no scope to consult and silently fell back to
heuristics on .hbs files.
Wires the existing `registerGlimmerScopes` helper into the HBS path
with a new `blockParamsOnly` mode, leaving free identifiers
(`{{path}}`, `<Tag>`) unregistered so they remain runtime-defined and
do not surface as no-undef errors. The global scope is rebound from a
stub Program to the real Program — analyzing the real Program directly
hits an esrecurse cycle on the Glimmer subtree's parent back-links.
Also adds an early-exit to `registerBlockParams` when there are no
block params to declare, which avoids creating empty BlockScopes that
slow `findParentScope`/`findVarInParentScopes` lookups (benefits the
gjs/gts path too).
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…svg-tags + scope Replaces the inverse component-detection heuristic with a whitelist of HTML and SVG tag names plus a scope check. With ember-tooling/ember-eslint-parser#189 populating block-param scope in HBS, lists + scope now works in both modes. Custom elements and unknown lowercase tags remain accepted false negatives.
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…params Replaces the manual block-param stack with sourceCode.getScope(node.parent) + a walk up the scope chain. GTS templates work today (36/37 tests pass). BLOCKED BY UPSTREAM: ember-tooling/ember-eslint-parser#189. The HBS parser currently builds an empty scope manager, so Glimmer block params aren't registered for .hbs files. The failing test `{{#let ... as |plaintext|}}<plaintext />` documents this gap and will start passing once PR 189 is merged and consumed here. Uses getScope(node.parent) rather than getScope(node) so an element's own `as |x|` params (attached to that element's block scope) don't shadow its own tag — e.g. `<marquee as |marquee|>` must still flag the outer <marquee>.
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…params Replaces the manual block-param stack with sourceCode.getScope(node.parent) + a walk up the scope chain. GTS templates work today (36/37 tests pass). BLOCKED BY UPSTREAM: ember-tooling/ember-eslint-parser#189. The HBS parser currently builds an empty scope manager, so Glimmer block params aren't registered for .hbs files. The failing test `{{#let ... as |plaintext|}}<plaintext />` documents this gap and will start passing once PR 189 is merged and consumed here. Uses getScope(node.parent) rather than getScope(node) so an element's own `as |x|` params (attached to that element's block scope) don't shadow its own tag — e.g. `<marquee as |marquee|>` must still flag the outer <marquee>.
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| * runtime-defined and must not surface as no-undef errors. | ||
| */ | ||
| export function registerGlimmerScopes(result) { | ||
| export function registerGlimmerScopes(result, { blockParamsOnly = false } = {}) { |
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I think it might be better to undo the changes to this function and instead export a registerHBSScopes function
…Scopes Addresses review: ember-tooling#189 (comment)
NullVoxPopuli
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Apr 16, 2026
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@NullVoxPopuli thanks for the quick review! Seems like npm publish failed in ci: https://github.com/ember-tooling/ember-eslint-parser/actions/runs/24485077427/job/71557984384 |
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ember-tooling/ember-eslint-parser#189 populates block-param scope for <foo as |x|> in HBS mode, so the rule's scope check in lib/rules/template-no-block-params-for-html-elements.js no longer relies on an empty scope manager in .hbs files. No observable test change on master (all tests here use <template>...</template> / GJS mode where scope already worked), but makes the scope-based detection correct in HBS too.
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Unblocks the HBS valid-case test
{{#let (component 'whatever-here') as |plaintext|}}
<plaintext />
{{/let}}
which relies on ember-tooling/ember-eslint-parser#189 populating block-
param scope in the hbs-parser. All 37 tests (GTS + HBS) pass.
This was referenced Apr 21, 2026
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Summary
Registers block-param scope in the HBS parser so
<Foo as |x|>and{{#let ... as |x|}}create proper variable bindings in the scope manager. Previously the HBS parser analyzed an empty stub Program, so no block params landed in any scope.Why
Came up reviewing ember-cli/eslint-plugin-ember#2689 (
template-no-block-params-for-html-elements). The lint rule's scope check is effectively dead code on.hbsfiles because the HBS parser never populates scope with template-defined variables — only the html-tag allowlist heuristic carries that case. Same gap likely affects any other rule that consults scope for HBS templates.Approach
registerHBSScopesintransforms.jsthat traverses the Glimmer AST and declares only block-param variables. Free identifiers ({{path}},<Tag>) are intentionally left unregistered so HBS keeps its "all template locals are runtime-defined" policy and no-undef stays quiet.registerGlimmerScopesis unchanged.hbs-parser.js, rebinds the analyzed global scope from a stub Program onto the real Program. Analyzing the real Program directly causes infinite recursion in esrecurse — the Glimmer subtree carries parent back-links.registerBlockParamswhen there are no block params, avoiding empty BlockScopes that would pollutefindParentScope/findVarInParentScopeslookups (also benefits the gjs/gts path).Test plan
<Foo as |x|>{{x}}</Foo>— block scope withxdeclared{{#let foo as |router|}}{{router}}{{/let}}— block scope withrouter<Foo as |a b c|>— multiple params each registered<Foo>hi</Foo>— no block scopes createdpnpm lintclean