Bring behavior of String.replace() in line with other engines

"x".replace("x", "$1") gives "$1" in both JSC and V8, as there are
no captures that could be used as a replacement for $1. Implement
the same behavior as it's the most logical thing to do (even though
it's undefined according to the spec).

Two digit captures ($nm) work in a way that they get applied if
$nm captures exist. If there are less than nm but more than n captures
available $n is replaced by the n'th capture and m is copied over
verbatim.

Change-Id: I8b5f576f2c42c8334859ab7854dcdf07104dd35b
Fixes: QTBUG-73152
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 59 insertions, 0 deletions

diff --git a/tests/auto/qml/qjsengine/tst_qjsengine.cpp b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
index cf7b9c7224..42d8f37ca8 100644
--- a/tests/auto/qml/qjsengine/tst_qjsengine.cpp
+++ b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
@@ -220,6 +220,8 @@ private slots:
     void functionToString_data();
     void functionToString();
 
+    void stringReplace();
+
     void protoChanges_QTBUG68369();
     void multilineStrings();
 
@@ -4367,6 +4369,63 @@ void tst_QJSEngine::functionToString()
     QCOMPARE(evaluationResult.toString(), expectedString);
 }
 
+void tst_QJSEngine::stringReplace()
+{
+    QJSEngine engine;
+
+    QJSValue val = engine.evaluate("'x'.replace('x', '$1')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$1"));
+
+    val = engine.evaluate("'x'.replace('x', '$10')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$10"));
+
+    val = engine.evaluate("'x'.replace('x', '$01')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$01"));
+
+    val = engine.evaluate("'x'.replace('x', '$0')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$0"));
+
+    val = engine.evaluate("'x'.replace('x', '$00')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$00"));
+
+    val = engine.evaluate("'x'.replace(/(x)/, '$1')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("x"));
+
+    val = engine.evaluate("'x'.replace(/(x)/, '$01')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("x"));
+
+    val = engine.evaluate("'x'.replace(/(x)/, '$2')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$2"));
+
+    val = engine.evaluate("'x'.replace(/(x)/, '$02')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$02"));
+
+    val = engine.evaluate("'x'.replace(/(x)/, '$0')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$0"));
+
+    val = engine.evaluate("'x'.replace(/(x)/, '$00')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("$00"));
+
+    val = engine.evaluate("'x'.replace(/()()()()()()()()()(x)/, '$11')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("1"));
+
+    val = engine.evaluate("'x'.replace(/()()()()()()()()()(x)/, '$10')");
+    QVERIFY(val.isString());
+    QCOMPARE(val.toString(), QString("x"));
+}
+
 void tst_QJSEngine::protoChanges_QTBUG68369()
 {
     QJSEngine engine;