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fix: catastrophic backtracking with struct tags after interface{}/struct{} #23

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Merged
worlpaker merged 2 commits into from
Feb 4, 2026
Merged

fix: catastrophic backtracking with struct tags after interface{}/struct{} #23

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b1e9d5d
fix: catastrophic backtracking with struct tags after interface{}/str…
philz Feb 3, 2026
7991107
address PR feedback: add " to exclusion set and add stress test
philz Feb 3, 2026
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4 changes: 2 additions & 2 deletions syntaxes/go.tmLanguage.json
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Original file line number Diff line number Diff line change
Expand Up @@ -1923,12 +1923,12 @@
},
{
"comment": "one line with semicolon(;) without formatting gofmt - single type | property variables and types",
"match": "(?:(?<=\\{)((?:\\s*(?:(?:(?:\\w+\\,\\s*)+)?(?:\\w+\\s+))?(?:(?:(?:\\s*(?:[\\*\\[\\]]+)?(?:\\<\\-\\s*)?\\bchan\\b(?:\\s*\\<\\-)?\\s*)+)?(?:[^\\s/]+)(?:\\;)?))+)\\s*(?=\\}))",
"match": "(?:(?<=\\{)((?:\\s*(?:(?:(?:\\w+\\,\\s*)+)?(?:\\w+\\s+))?(?:(?:(?:\\s*(?:[\\*\\[\\]]+)?(?:\\<\\-\\s*)?\\bchan\\b(?:\\s*\\<\\-)?\\s*)+)?(?:[^\\s/\\`\"]+)(?:\\;)?))+)\\s*(?=\\}))",
"captures": {
"1": {
"patterns": [
{
"match": "(?:((?:(?:\\w+\\,\\s*)+)?(?:\\w+\\s+))?((?:(?:\\s*(?:[\\*\\[\\]]+)?(?:\\<\\-\\s*)?\\bchan\\b(?:\\s*\\<\\-)?\\s*)+)?(?:[^\\s/]+)(?:\\;)?))",
"match": "(?:((?:(?:\\w+\\,\\s*)+)?(?:\\w+\\s+))?((?:(?:\\s*(?:[\\*\\[\\]]+)?(?:\\<\\-\\s*)?\\bchan\\b(?:\\s*\\<\\-)?\\s*)+)?(?:[^\\s/\\`\"]+)(?:\\;)?))",
"captures": {
"1": {
"patterns": [
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11 changes: 11 additions & 0 deletions test/semantic_tokens.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4974,3 +4974,14 @@ func weDontKnowIfIsTypeOrVariable(name string, born time.Time) ([]byte, error) {
Age: new(age),
})
}

// Shiki JS engine catastrophic backtracking with long struct tags
// See: https://github.com/shikijs/shiki/issues/1026 (similar issue with comments)
// Time grows exponentially O(4^n) with tag length when using JavaScript regex engine

type BacktrackTest struct {
ShortTag string `json:"short"`
MediumTag string `json:"medium_length_tag"`
LongTag interface{} `json:"this_is_a_very_long_tag_name"`
WithOptions interface{} `json:"field_name,omitempty"`
}
61 changes: 61 additions & 0 deletions test/semantic_tokens.go.snap
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Original file line number Diff line number Diff line change
Expand Up @@ -48003,4 +48003,65 @@
# ^ source.go punctuation.definition.end.bracket.round.go
>}
#^ source.go punctuation.definition.end.bracket.curly.go
>
>// Shiki JS engine catastrophic backtracking with long struct tags
#^^ source.go comment.line.double-slash.go punctuation.definition.comment.go
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ source.go comment.line.double-slash.go
>// See: https://github.com/shikijs/shiki/issues/1026 (similar issue with comments)
#^^ source.go comment.line.double-slash.go punctuation.definition.comment.go
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ source.go comment.line.double-slash.go
>// Time grows exponentially O(4^n) with tag length when using JavaScript regex engine
#^^ source.go comment.line.double-slash.go punctuation.definition.comment.go
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ source.go comment.line.double-slash.go
>
>type BacktrackTest struct {
#^^^^ source.go keyword.type.go
# ^ source.go
# ^^^^^^^^^^^^^ source.go entity.name.type.go
# ^ source.go
# ^^^^^^ source.go keyword.struct.go
# ^ source.go
# ^ source.go punctuation.definition.begin.bracket.curly.go
> ShortTag string `json:"short"`
#^ source.go
# ^^^^^^^^ source.go variable.other.property.go
# ^^^^ source.go
# ^^^^^^ source.go storage.type.string.go
# ^^^^^^ source.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.begin.go
# ^^^^^^^^^^^^ source.go string.quoted.raw.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.end.go
> MediumTag string `json:"medium_length_tag"`
#^ source.go
# ^^^^^^^^^ source.go variable.other.property.go
# ^^^ source.go
# ^^^^^^ source.go storage.type.string.go
# ^^^^^^ source.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.begin.go
# ^^^^^^^^^^^^^^^^^^^^^^^^ source.go string.quoted.raw.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.end.go
> LongTag interface{} `json:"this_is_a_very_long_tag_name"`
#^ source.go
# ^^^^^^^ source.go variable.other.property.go
# ^^^^^ source.go
# ^^^^^^^^^ source.go keyword.interface.go
# ^ source.go punctuation.definition.begin.bracket.curly.go
# ^ source.go punctuation.definition.end.bracket.curly.go
# ^ source.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.begin.go
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ source.go string.quoted.raw.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.end.go
> WithOptions interface{} `json:"field_name,omitempty"`
#^ source.go
# ^^^^^^^^^^^ source.go variable.other.property.go
# ^ source.go
# ^^^^^^^^^ source.go keyword.interface.go
# ^ source.go punctuation.definition.begin.bracket.curly.go
# ^ source.go punctuation.definition.end.bracket.curly.go
# ^ source.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.begin.go
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^ source.go string.quoted.raw.go
# ^ source.go string.quoted.raw.go punctuation.definition.string.end.go
>}
#^ source.go punctuation.definition.end.bracket.curly.go
>
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