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roidelapluie merged 2 commits into from
May 6, 2026
Merged

promql/parser: recognize range in duration expressions #18623

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483db93
promql/parser: recognize range in duration expressions
roidelapluie May 6, 2026
8739d37
promql/parser: use map-based dispatch for duration keyword lexing
roidelapluie May 6, 2026
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54 changes: 34 additions & 20 deletions promql/parser/lex.go
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Original file line number Diff line number Diff line change
Expand Up @@ -499,15 +499,15 @@ func lexStatements(l *Lexer) stateFn {
l.backup()
return lexKeywordOrIdentifier
}
switch r {
case ':':
switch {
case r == ':':
if l.gotColon {
return l.errorf("unexpected colon %q", r)
}
l.emit(COLON)
l.gotColon = true
return lexStatements
case 's', 'S', 'm', 'M':
case isDurationKeywordStartChar(r):
if l.scanDurationKeyword() {
return lexStatements
}
Expand Down Expand Up @@ -935,31 +935,45 @@ func lexNumber(l *Lexer) stateFn {
return lexStatements
}

// durationKeywordTokens maps lowercase duration keyword names to their token types.
var durationKeywordTokens = map[string]ItemType{
"step": STEP,
"range": RANGE,
"min": MIN,
"max": MAX,
}

// durationKeywordStartChars is the set of lowercase runes that can start a duration keyword,
// derived from durationKeywordTokens.
var durationKeywordStartChars = makeDurationKeywordStartChars()

func makeDurationKeywordStartChars() map[rune]struct{} {
m := make(map[rune]struct{}, len(durationKeywordTokens))
for kw := range durationKeywordTokens {
m[rune(kw[0])] = struct{}{}
}
return m
}

// isDurationKeywordStartChar reports whether r can be the first character of a duration keyword.
func isDurationKeywordStartChar(r rune) bool {
_, ok := durationKeywordStartChars[unicode.ToLower(r)]
return ok
}

func (l *Lexer) scanDurationKeyword() bool {
for {
switch r := l.next(); {
case isAlpha(r):
// absorb.
default:
l.backup()
word := l.input[l.start:l.pos]
kw := strings.ToLower(word)
switch kw {
case "step":
l.emit(STEP)
return true
case "range":
l.emit(RANGE)
return true
case "min":
l.emit(MIN)
word := strings.ToLower(l.input[l.start:l.pos])
if tok, ok := durationKeywordTokens[word]; ok {
l.emit(tok)
return true
case "max":
l.emit(MAX)
return true
default:
return false
}
return false
}
}
}
Expand Down Expand Up @@ -1239,7 +1253,7 @@ func lexDurationExpr(l *Lexer) stateFn {
case r == ',':
l.emit(COMMA)
return lexDurationExpr
case r == 's' || r == 'S' || r == 'm' || r == 'M' || r == 'r' || r == 'R':
case isDurationKeywordStartChar(r):
if l.scanDurationKeyword() {
return lexDurationExpr
}
Expand Down
26 changes: 26 additions & 0 deletions promql/parser/parse_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4718,6 +4718,32 @@ var testExpr = []struct {
EndPos: 12,
},
},
{
input: `foo[2m/range()]`,
expected: &MatrixSelector{
VectorSelector: &VectorSelector{
Name: "foo",
LabelMatchers: []*labels.Matcher{
MustLabelMatcher(labels.MatchEqual, model.MetricNameLabel, "foo"),
},
PosRange: posrange.PositionRange{Start: 0, End: 3},
},
RangeExpr: &DurationExpr{
Op: DIV,
LHS: &NumberLiteral{
Val: 120,
Duration: true,
PosRange: posrange.PositionRange{Start: 4, End: 6},
},
RHS: &DurationExpr{
Op: RANGE,
StartPos: 7,
EndPos: 14,
},
},
EndPos: 15,
},
},
{
input: `foo[-range()]`,
expected: &MatrixSelector{
Expand Down
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