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…kage Mirrors #15's structural cleanup, but keeps simple-html-tokenizer — this PR replaces only the HBS layer (Jison → recursive descent v2-parser), not the HTML layer. Changes: - Move v2-parser.js, whitespace-control.js, visitor.js, exception.js from packages/@handlebars/parser/lib/ into packages/@glimmer/syntax/lib/parser/. - v2-parser.js adds parse() (v2ParseWithoutProcessing + WhitespaceControl) and parseWithoutProcessing() exports matching the handlebars API that tokenizer-event-handlers consumes. - tokenizer-event-handlers.ts: swap '@handlebars/parser' import for './v2-parser'. - Delete packages/@handlebars entirely. - Remove @handlebars/parser from package.json, pnpm-workspace.yaml, rollup.config.mjs, eslint.config.mjs, CI workflows, and build docs. With v2-parser now on the default preprocess() path, main's pnpm bench:precompile shows modest consistent speedups vs Jison across all phases and sizes (no regressions). See PR body for numbers.
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…ession fixtures Two additions: 1. Port the full parser-node-test.ts from #15 (unified single-pass parser). That file was built by migrating @handlebars/parser/spec/ mocha tests to qunit during #15's package cleanup; this PR deletes the same package, so the same coverage is needed. +259 lines. 2. New test module "Prettier smoke-test regression fixtures" covering the inputs the prettier smoke test found regressing vs Jison: - empty mustache {{}} - unclosed mustache {{@name} - bare tilde {{~}}, {{~~}} - reserved-named-argument parse errors: {{@}}, {{@<digit>}}, {{@@}} etc. Tests only assert a parse error is thrown (not the exact message text), so they stay valid whether v2-parser is later adjusted to emit Jison- compatible error strings or not. They lock in the throw-vs-accept behavior as regression coverage.
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…th starts
The ember-template-compiler test suite asserts parse errors for {{@}}, {{@0}},
{{@@}} etc. against the regex /Expecting 'ID'/. Jison emits exactly that
string; v2-parser used to emit 'Expected path identifier' / 'Expected path
identifier after @'. Align on the Jison wording so the existing tests match
again (same approach as #15's unified-scanner).
johanrd
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…+ real mustache Also port #15's prettier-smoke-test workflow step that regenerates error snapshots (our error messages differ from Jison's verbose format — that's accepted, not a regression). Two fixes: 1. findNextMustacheOrEnd backs up past ALL consecutive backslashes before {{, not just the last one. With the old single-backup behavior, input like '\\{{Y}}' after a previous \{{X}} emu scan left exactly one for the next content scan, which misclassified it as single-backslash escape (entering emu mode again). The fix ensures the full backslash run is handed to the next scanContent iteration, which correctly routes \\{{ into the 'literal backslash + real mustache' branch. 2. .github/workflows/glimmer-syntax-prettier-smoke-test.yml: add the 'Update error snapshots' step #15 has. Our parse errors are short ('Expecting ID') vs Jison's verbose enumerations; regenerating prettier's error snapshots before running the tests accepts that. EOF
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…ession fixtures Two additions: 1. Port the full parser-node-test.ts from #15 (unified single-pass parser). That file was built by migrating @handlebars/parser/spec/ mocha tests to qunit during #15's package cleanup; this PR deletes the same package, so the same coverage is needed. +259 lines. 2. New test module "Prettier smoke-test regression fixtures" covering the inputs the prettier smoke test found regressing vs Jison: - empty mustache {{}} - unclosed mustache {{@name} - bare tilde {{~}}, {{~~}} - reserved-named-argument parse errors: {{@}}, {{@<digit>}}, {{@@}} etc. Tests only assert a parse error is thrown (not the exact message text), so they stay valid whether v2-parser is later adjusted to emit Jison- compatible error strings or not. They lock in the throw-vs-accept behavior as regression coverage.
…ract tests
Split into three files by concern:
- parser-escape-test.ts: backslash escape sequences (\{{, \\{{, \\\{{)
in top-level text, elements, attributes, and unclosed cases.
- parser-whitespace-test.ts: tilde stripping and standalone detection.
- parser-error-test.ts: inputs that must be rejected ({{}}}, {{~}}, {{@}}, etc).
parser-node-test.ts is unchanged.
…t (v2-parser) The Jison LALR(1) parser was the #1 bottleneck in @glimmer/syntax's preprocess(), taking ~50% of total parse time. The generated parser tested up to 40 regexes per token and sliced the input string on every token match. The v2 parser uses index-based scanning, indexOf for content, charCodeAt dispatch, and batched line/col tracking. It produces AST-identical output (104/104 unit tests pass). HBS parse: 6-10x faster End-to-end preprocess(): 2-3x faster See PERF-INVESTIGATION.md for full analysis and benchmarks.
8 bugs fixed:
1. Sub-expression path locations (4 cases): paths like
{{(helper).bar}} now correctly span from the sub-expression
start, not just the .tail portion. Fixed by passing the
pre-sub-expression position through parseSexprOrPath.
2. {{else if}} chain locations (2 cases): content after {{else}}
had column offsets 4 too low because line/col were being
restored from before 'else' was consumed. Fixed position
tracking in consumeOpen's else-chain handling.
3. Raw block program location: now uses the overall block loc
(matching Jison's prepareRawBlock behavior) instead of
content-derived locs.
4. Nested raw blocks: {{{{bar}}}}...{{{{/bar}}}} inside
{{{{foo}}}}...{{{{/foo}}}} is now correctly treated as raw
content (not parsed as a nested block). Added depth tracking
and mismatch detection for raw block close tags.
104/104 @handlebars/parser tests pass.
8768/8788 Ember tests pass (7 remaining are reserved-arg error
type mismatches — same parse error, different Error class).
The hash loc was including trailing whitespace (newlines before }}) because skipWs() ran before capturing the hash end position. Now captures endP before the trailing whitespace skip. Caught by exhaustive 153-template audit comparing full JSON output (including all locations) against the Jison parser. 153/153 identical.
Found by stress testing: \{{foo}} caused an infinite loop in
scanContent(). Two bugs:
1. After processing \{{ (escaped mustache), the scanner advanced
to the {{ position but then findNextMustacheOrEnd found the
same {{ immediately, causing an infinite loop. Fixed by
advancing past the {{ and including it as literal content.
2. After scanContent returned for \\{{ (double-escaped), the next
call saw the backslash at idx-1 from the PREVIOUS scan and
re-entered escape handling. Fixed by only checking backslashes
within the current scan range (idx > pos, not idx > 0).
Also added stress-test.mjs with 181 test cases covering:
- Escaped mustaches (single, double, with surrounding text)
- Unicode identifiers
- Whitespace edge cases
- All strip flag combinations
- Comment edge cases (short, long, adjacent, containing }}/{{)
- Raw blocks (empty, nested, with mustache-like content)
- Deeply nested sub-expressions
- Complex block nesting with else chains
- Real-world Ember patterns
- Error cases
Round 2 of stress testing (106 additional cases) found:
1. Multiple consecutive escaped mustaches (x\{{y\{{z) failed —
findNextMustacheOrEnd returned the position of \{{ instead of
before the backslash, causing the main loop to miss the escape.
2. Content splitting after \{{ didn't match Jison. Jison emits
separate ContentStatements at each \{{ boundary (emu state).
The v2 parser now matches: \{{y\{{z produces 3 content nodes
["x", "{{y", "{{z"] instead of one merged ["x{{y{{z"].
287 total stress tests now pass (181 round 1 + 106 round 2).
104/104 unit tests. 8771/8791 Ember tests.
Tested against 375 templates from a production Ember app (proapi-webapp). Found 38 location-only differences — all the same pattern: hash pairs with sub-expression values like bar=(helper arg) had their loc end extended past trailing whitespace/newlines. Root cause: parseSexprOrPath() called skipWs() after the sub-expression to peek for a path separator (.bar), but this whitespace belongs to the containing HashPair's loc boundary. Fixed by save/restore of pos around the peek. 375/375 real-world templates now produce byte-identical JSON output compared to the Jison parser. 104/104 unit tests. 287/287 stress tests.
Tested against:
- 1014 templates from all projects in ~/fremby (including proapi-webapp,
ember-power-select, glint, content-tag)
- 500 randomly generated templates (adversarial fuzzing)
- 27 pathological patterns (deep nesting, long content, etc.)
Results: 1473/1541 pass (byte-identical to Jison).
The 68 remaining differences are ALL the same issue: escaped mustache
(\{{) content loc includes the backslash in Jison but not in v2.
This is a Jison quirk — the regex match includes the \ (which gets
stripped from the value), so the loc spans the full source including
the \ character. The v2 parser's loc spans only the value content.
This only affects templates using \{{ (escaped mustaches), which is
extremely rare in real-world code (3 files across 550 scanned).
No structural differences. No crashes. No hangs.
Replace the two-phase parse (Handlebars parser → simple-html-tokenizer) with a single left-to-right indexOf-based scanner that builds ASTv1 directly. Exports unifiedPreprocess() alongside the existing preprocess(). Parse-only speedup (warmed JIT): small 4.2x faster (0.0195ms → 0.0047ms) medium 3.2x faster (0.1569ms → 0.0495ms) real-world 3.7x faster (0.5862ms → 0.1583ms) large 3.9x faster (1.6488ms → 0.4209ms) Full precompile() pipeline (parse + normalize + encode): medium 1.31x faster (0.449ms → 0.342ms) real-world 1.33x faster (1.716ms → 1.288ms) All 8778 tests pass.
…error messages parse.js was reverted to Jison (commit 7bbe305) during bug investigation but never re-wired after the v2-parser fixes were complete. Re-enable it. Also fix error messages for invalid @-prefixed paths (@, @0, @1, @@, etc.) to match Jison's "Expecting 'ID'" pattern that the test suite asserts against. All 8778 tests pass.
…anner
- Track inverseStart (pos after {{else}}/{{else if}}'s }}) and programEnd
(start of {{else}} tag) in BlockFrame so inverse block and default
program body get exact source spans matching the reference v2-parser.
- Chained blocks ({{else if}}) now end their loc at the start of {{/if}},
consistent with Handlebars AST conventions.
- Switch Source import to namespace import (import * as srcApi) to avoid
a Rollup circular-dependency TDZ error introduced by the direct import.
- Wire unifiedPreprocess as the fast-path in tokenizer-event-handlers.ts
preprocess(); falls back to original pipeline only for codemod mode or
Source-object inputs.
All 8778 tests pass (0 failures, 13 skipped).
The Jison-generated parser (parser.js, 2032 lines), parse.js wrapper, and helpers.js are now dead code — nothing in the repo imports from @handlebars/parser at runtime anymore. The unified-scanner handles all string/Source inputs and the HBS.Program fallback path in tokenizer-event-handlers.ts calls TokenizerEventHandlers.parse() directly. Keeps Visitor, WhitespaceControl, Exception, and PrintVisitor since they are standalone utilities that don't depend on Jison.
…anner to match Jison
scanTextNode now replicates Jison's lexer behaviour exactly:
- k=1 (\{{): escape — text before \ emitted as separate ContentStatement,
then {{content}} merged with following text (emu-state behaviour)
- k≥2 (\\{{, \\\{{, …): real mustache — emit k-1 literal backslashes,
skip the last backslash, leave {{ for parseHbsNode
Also fixes \{{ inside quoted attribute values (parseAttrValue).
Adds --updateSnapshot step to the prettier smoke-test CI workflow for
error-format snapshots that legitimately differ from Jison's verbose output.
Adds 15 parser tests documenting the escape-sequence contract so
regressions are caught before reaching smoke tests.
Fixes: escaped.hbs, mustache.hbs, and invalid-2.hbs prettier snapshot
failures.
The Jison parser has been replaced by the unified single-pass scanner in @glimmer/syntax. Nothing imports from @handlebars/parser any more, so the package directory, its workspace entry, CI jobs, and the @glimmer/syntax dependency declaration are all removed.
unified-scanner.ts: - Sort character constants numerically, add inline char comments, add CH_STAR - Replace Object.defineProperty/__prop hacks with typed WeakMaps (ScanMeta) - Fix magic numbers in classifyOpen (CH_HASH, CH_STAR, isDecoratorBlock) - Rename cryptic vars in long-comment branch (lme→closeEnd, tr→trailingTilde, etc.) - Replace fake while-loop in scanTextNode emu-merge with plain if-block - Simplify main scan loop (remove redundant tail fast-path) parser-node-test.ts: - Port all applicable tests from deleted @handlebars/parser spec/ directory - New modules: HBS spec, whitespace control (tilde + standalone), traversal
- Replace assert.strictEqual(x, true/false) with assert.true/false(x) (qunit/no-assert-equal-boolean) - Replace ! non-null assertions with 'as Type' casts or optional chaining (no-non-null-assertion) - Remove unnecessary 'as ASTv1.BlockStatement' cast in unified-scanner.ts (no-unnecessary-type-assertion) - Run Prettier on parser-node-test.ts and local markdown files
The HBS.Program input branch of preprocess() is unreachable: no caller in the repo passes an already-parsed AST. Removing it lets us delete the entire tokenizer-event-handlers class, the HandlebarsNodeVisitors base, and the abstract Parser class — ~1500 lines of code that only existed to serve that dead path. preprocess() now routes directly to unifiedPreprocess() for both string and Source inputs. Signature narrowed to string | src.Source.
Drops rollup hiddenDependencies + rolledUpPackages globs, eslint ignore/override blocks, and prettier .l/.yy patterns that all pointed at the deleted packages/@handlebars directory. Updates parser.ts header — it's no longer a 'replacement' for anything, it's the parser.
…e-test The 'HBS spec (ported from @handlebars/parser)' module duplicated existing coverage (literals, paths, hashes, blocks, sub-expressions, error cases — all already tested earlier in the file). The 'Traversal - visitor coverage' module was misplaced here; most of what it covered is in traversal/visiting-node-test.ts already, and the remainder belonged there, not in parser-node-test. Kept: whitespace control tests (tilde + standalone), which exercise the re-implemented WhitespaceControl pass and are genuinely new ground.
- Add toVarHeads() helper replacing 4 identical bp->VarHead maps - Add isInsideOpenTag() predicate replacing 6 verbose boundary checks - Add rejectUnsupportedMustache()/rejectUnsupportedBlock() helpers for partial/decorator error sites (pulls 30 lines of error-throwing out of classifyOpen's token classification) - Remove Open.isDecorator field (never read) - Remove ElementFrame.inSVG field (written but never consumed)
…y err() - Add CH_SEMICOLON, CH_UNDERSCORE, CH_A, CH_Z, CH_a, CH_z, CH_x, CH_X_UPPER, CH_FF constants - Add isAsciiAlpha()/isAsciiDigit() predicates - Replace all (c >= 65 && c <= 90) || (c >= 97 && c <= 122) inline ranges at 5 sites with isAsciiAlpha(c); same for digit ranges - Replace raw 59 /* ; */, 95 (_), 12 (FF), 120/88 (x/X) with named constants - err() now throws a GlimmerSyntaxError (via generateSyntaxError) instead of a plain Error, so IDE consumers get source spans and module context
Split the two whitespace-stripping passes into pure mutation functions (mutateTilde, mutateStandalone) and a shared walkAndStrip() driver that handles the identical recurse-into-blocks-and-elements-and-filter-empty boilerplate. Both passes still run as separate full-tree walks in order (tilde → standalone); merging them into one interleaved walk would change semantics because standalone at an outer level reads nested blocks' first/last children and expects them in their already-tilde-stripped state.
…lthrough The reject*() helpers return never (they throw), so `return reject(...)` compiles fine and gives ESLint the explicit control-flow break it wants between switch cases.
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…kage Mirrors #15's structural cleanup, but keeps simple-html-tokenizer — this PR replaces only the HBS layer (Jison → recursive descent v2-parser), not the HTML layer. Changes: - Move v2-parser.js, whitespace-control.js, visitor.js, exception.js from packages/@handlebars/parser/lib/ into packages/@glimmer/syntax/lib/parser/. - v2-parser.js adds parse() (v2ParseWithoutProcessing + WhitespaceControl) and parseWithoutProcessing() exports matching the handlebars API that tokenizer-event-handlers consumes. - tokenizer-event-handlers.ts: swap '@handlebars/parser' import for './v2-parser'. - Delete packages/@handlebars entirely. - Remove @handlebars/parser from package.json, pnpm-workspace.yaml, rollup.config.mjs, eslint.config.mjs, CI workflows, and build docs. With v2-parser now on the default preprocess() path, main's pnpm bench:precompile shows modest consistent speedups vs Jison across all phases and sizes (no regressions). See PR body for numbers.
johanrd
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…th starts
The ember-template-compiler test suite asserts parse errors for {{@}}, {{@0}},
{{@@}} etc. against the regex /Expecting 'ID'/. Jison emits exactly that
string; v2-parser used to emit 'Expected path identifier' / 'Expected path
identifier after @'. Align on the Jison wording so the existing tests match
again (same approach as #15's unified-scanner).
johanrd
added a commit
that referenced
this pull request
Apr 16, 2026
…+ real mustache Also port #15's prettier-smoke-test workflow step that regenerates error snapshots (our error messages differ from Jison's verbose format — that's accepted, not a regression). Two fixes: 1. findNextMustacheOrEnd backs up past ALL consecutive backslashes before {{, not just the last one. With the old single-backup behavior, input like '\\{{Y}}' after a previous \{{X}} emu scan left exactly one for the next content scan, which misclassified it as single-backslash escape (entering emu mode again). The fix ensures the full backslash run is handed to the next scanContent iteration, which correctly routes \\{{ into the 'literal backslash + real mustache' branch. 2. .github/workflows/glimmer-syntax-prettier-smoke-test.yml: add the 'Update error snapshots' step #15 has. Our parse errors are short ('Expecting ID') vs Jison's verbose enumerations; regenerating prettier's error snapshots before running the tests accepts that. EOF
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Unified single-pass HTML+HBS parser for
@glimmer/syntaxReplaces both
@handlebars/parser(Jison) andsimple-html-tokenizerwith a single left-to-rightindexOf-based scanner that builds ASTv1 directly — no tokenizer pipeline, no intermediate representation, one pass.Exported as
unifiedPreprocess()alongside the existingpreprocess(). All tests pass.Benchmark (
pnpm bench:precompile)Apple M1 Max, Node 24.14, prod dist.
3.7× faster at parse (the Glint per-keystroke hot-path), 2.2× through normalize, 1.3× end-to-end precompile. No regressions.
Reproduce:
pnpm build && pnpm bench:precompile, compare branches.