From 319068a7a6ebadae1f3569cf4f471b46e7d333fa Mon Sep 17 00:00:00 2001
From: Fabian Reinartz <fab.reinartz@gmail.com>
Date: Thu, 4 Jun 2015 18:21:24 +0200
Subject: [PATCH] promql: fix parsing ambiguity for serial repetitions

---
 promql/lex.go        | 12 +++++++-----
 promql/parse_test.go |  7 +++++++
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/promql/lex.go b/promql/lex.go
index 189d58ac2..552ed6917 100644
--- a/promql/lex.go
+++ b/promql/lex.go
@@ -666,7 +666,8 @@ func lexNumberOrDuration(l *lexer) stateFn {
 // not necessarily a valid number. This case is caught by the parser.
 func (l *lexer) scanNumber() bool {
 	digits := "0123456789"
-	if l.accept("0") && l.accept("xX") {
+	// Disallow hexal in series descriptions as the syntax is ambiguous.
+	if !l.seriesDesc && l.accept("0") && l.accept("xX") {
 		digits = "0123456789abcdefABCDEF"
 	}
 	l.acceptRun(digits)
@@ -677,11 +678,12 @@ func (l *lexer) scanNumber() bool {
 		l.accept("+-")
 		l.acceptRun("0123456789")
 	}
-	// Next thing must not be alphanumeric.
-	if isAlphaNumeric(l.peek()) && !l.seriesDesc {
-		return false
+	// Next thing must not be alphanumeric unless it's the times token
+	// for series repetitions.
+	if r := l.peek(); (l.seriesDesc && r == 'x') || !isAlphaNumeric(r) {
+		return true
 	}
-	return true
+	return false
 }
 
 // lexIdentifier scans an alphanumeric identifier. The next character
diff --git a/promql/parse_test.go b/promql/parse_test.go
index dfeac7eec..c50b8413c 100644
--- a/promql/parse_test.go
+++ b/promql/parse_test.go
@@ -1274,6 +1274,13 @@ var testSeries = []struct {
 			"a": "b",
 		},
 		expectedValues: newSeq(1, 2, 3, -7, -17, -27, -37),
+	}, {
+		input: `my_metric{a="b"} 1 2 3-0x4`,
+		expectedMetric: clientmodel.Metric{
+			clientmodel.MetricNameLabel: "my_metric",
+			"a": "b",
+		},
+		expectedValues: newSeq(1, 2, 3, 3, 3, 3, 3),
 	}, {
 		input: `my_metric{a="b"} 1 3 _ 5 _x4`,
 		expectedMetric: clientmodel.Metric{