Fix string.find end index

Author: zombiezen

internal/lua/stringlib.go

@@ -203,7 +203,7 @@ func stringFind(ctx context.Context, l *State) (int, error) {
 		return 1, nil
 	}
 	l.PushInteger(int64(init) + int64(matches[0]) + 1)
-	l.PushInteger(int64(init) + int64(matches[1]) + 1)
+	l.PushInteger(int64(init) + int64(matches[1]))
 	n, err := pushSubmatches(l, init, matches[2:], positionCaptures)
 	if err != nil {
 		return 0, fmt.Errorf("%s%v", Where(l, 1), err)

internal/lua/stringlib_test.go

@@ -105,6 +105,12 @@ var patternTests []patternTest = []patternTest{
 			{"1 2 3 4 5", []int{0, 1}},
 		},
 	},
+	{
+		pattern: "%l*",
+		tests: []submatchIndexTest{
+			{"aloALO", []int{0, 3}},
+		},
+	},
 }
 
 var badPatternTests = []string{