From c46ee7df57c30c94107df8506d30d8872ffa3baa Mon Sep 17 00:00:00 2001
From: Fabian Kosmale <fabian.kosmale@qt.io>
Date: Wed, 25 May 2022 09:07:37 +0200
Subject: QStringConverter: Do not crash if invalid

Attempting to use an invalid QStringConverter would so far have resulted
in a crash, as we would dereference the null iface pointer.
Fix this by inserting adequate checks, and ensure that hasError returns
true if we attempt to en/decode with an invalid converter.

Pick-to: 6.2 6.3
Change-Id: Icf74bb88cd8c95685481cc0bd512da99b62f33e6
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 .../text/qstringconverter/tst_qstringconverter.cpp | 56 ++++++++++++++++++++++
 1 file changed, 56 insertions(+)

(limited to 'tests/auto/corelib')

diff --git a/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp b/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
index 6fe20b1453..231df0390e 100644
--- a/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
+++ b/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
@@ -120,6 +120,8 @@ private slots:
 
     void constructByName();
 
+    void invalidConverter();
+
     void convertUtf8_data();
     void convertUtf8();
     void convertUtf8CharByChar_data() { convertUtf8_data(); }
@@ -181,6 +183,60 @@ void tst_QStringConverter::constructByName()
     QVERIFY(!strcmp(decoder.name(), "UTF-16"));
 }
 
+void tst_QStringConverter::invalidConverter()
+{
+    // QStringEncoder tests
+    {
+        QStringEncoder encoder;
+        QVERIFY(!encoder.isValid());
+        QVERIFY(!encoder.name());
+        QByteArray encoded = encoder(u"Some text");
+        QVERIFY(encoded.isEmpty());
+        QVERIFY(encoder.hasError());
+
+        encoder.resetState();
+        QVERIFY(!encoder.hasError());
+
+        encoded = encoder.encode(u"More text");
+        QVERIFY(encoded.isEmpty());
+        QVERIFY(encoder.hasError());
+        QCOMPARE(encoder.requiredSpace(42), 0);
+
+        encoder.resetState();
+        QVERIFY(!encoder.hasError());
+        char buffer[100];
+        char *position = encoder.appendToBuffer(buffer, u"Even more");
+        QCOMPARE(position, buffer);
+        QVERIFY(encoder.hasError());
+    }
+
+    // QStringDecoder tests
+    {
+        QStringDecoder decoder;
+        QVERIFY(!decoder.name());
+        QVERIFY(!decoder.isValid());
+        QString decoded = decoder("Some text");
+        QVERIFY(decoded.isEmpty());
+        QVERIFY(decoder.hasError());
+
+        decoder.resetState();
+        QVERIFY(!decoder.hasError());
+
+        decoded = decoder.decode("More text");
+        QVERIFY(decoded.isEmpty());
+        QVERIFY(decoder.hasError());
+
+        QCOMPARE(decoder.requiredSpace(42), 0);
+
+        decoder.resetState();
+        QVERIFY(!decoder.hasError());
+        QChar buffer[100];
+        QChar *position = decoder.appendToBuffer(buffer, "Even more");
+        QCOMPARE(position, buffer);
+        QVERIFY(decoder.hasError());
+    }
+}
+
 void tst_QStringConverter::convertUtf8_data()
 {
     QTest::addColumn<QStringConverter::Encoding>("encoding");
-- 
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