Fix a crash

walles · Nov 6, 2019 · ea3dcf3 · ea3dcf3
1 parent fb3b6ab
commit ea3dcf3
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Showing 2 changed files with 17 additions and 0 deletions.
diff --git a/m/matchRanges.go b/m/matchRanges.go
@@ -24,6 +24,11 @@ func _ToRunePositions(byteIndices [][]int, matchedString *string) [][2]int {
 
 	var returnMe [][2]int
 
+	if len(byteIndices) == 0 {
+		// Nothing to see here, move along
+		return returnMe
+	}
+
 	fromByte := byteIndices[len(returnMe)][0]
 	toByte := byteIndices[len(returnMe)][1]
 	fromRune := -1

diff --git a/m/matchRanges_test.go b/m/matchRanges_test.go
@@ -51,3 +51,15 @@ func TestUtf8(t *testing.T) {
 	assert.Assert(t, matchRanges.InRange(3))  // ä
 	assert.Assert(t, !matchRanges.InRange(4)) // -
 }
+
+func TestNoMatch(t *testing.T) {
+	// This test verifies that the match ranges are by rune rather than by byte
+	unicodes := "gris"
+	matchRanges := GetMatchRanges(&unicodes, regexp.MustCompile("apa"))
+
+	assert.Assert(t, !matchRanges.InRange(0))
+	assert.Assert(t, !matchRanges.InRange(1))
+	assert.Assert(t, !matchRanges.InRange(2))
+	assert.Assert(t, !matchRanges.InRange(3))
+	assert.Assert(t, !matchRanges.InRange(4))
+}