Make the `PREFIX` Parameter of the `qt_add_resources` Optional

The `rcc_PREFIX` will be set to `/` if it is not passed to the
function and it is not defined in `QT_RESOURCE_PREFIX`.

I also removed an unnecessary check of the `rcc_PREFIX`.

[ChangeLog][QtCore][CMake] The `PREFIX` parameter of the
`qt_add_resources` is now optional. If not passed, and
`QT_RESOURCE_PREFIX` is not defined, `/` will be used as the path
prefix.

Fixes: QTBUG-104938
Change-Id: I6524ab5dc54f035272e4c2e3154eb67591efb650
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>

4 files changed, 53 insertions, 0 deletions

diff --git a/tests/auto/cmake/CMakeLists.txt b/tests/auto/cmake/CMakeLists.txt
index afc6002ff6..f86f2ac720 100644
--- a/tests/auto/cmake/CMakeLists.txt
+++ b/tests/auto/cmake/CMakeLists.txt
@@ -158,6 +158,7 @@ if (NOT NO_WIDGETS)
     _qt_internal_test_expect_pass(test_dependent_modules)
     _qt_internal_test_expect_pass("test(needsquoting)dirname")
 endif()
+_qt_internal_test_expect_pass(test_add_resource_prefix BINARY test_add_resource_prefix)
 _qt_internal_test_expect_build_fail(test_add_resource_options)
 _qt_internal_test_expect_build_fail(test_wrap_cpp_options)
 _qt_internal_test_expect_pass(test_platform_defs_include)
diff --git a/tests/auto/cmake/test_add_resource_prefix/CMakeLists.txt b/tests/auto/cmake/test_add_resource_prefix/CMakeLists.txt
new file mode 100644
index 0000000000..65faa4cb09
--- /dev/null
+++ b/tests/auto/cmake/test_add_resource_prefix/CMakeLists.txt
@@ -0,0 +1,25 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.16)
+
+project(test_add_resource_prefix)
+
+find_package(Qt6 REQUIRED
+    COMPONENTS Core Test
+)
+
+set(CMAKE_AUTOMOC ON)
+
+add_executable(test_add_resource_prefix main.cpp)
+
+# Tests if "/" is being used when PREFIX is missing
+qt_add_resources(test_add_resource_prefix "resources_without_prefix"
+    FILES resource_file.txt)
+
+# Tests if the PREFIX parameter is being respected
+qt_add_resources(test_add_resource_prefix "resources_with_prefix"
+    PREFIX "/resources"
+    FILES resource_file.txt)
+
+target_link_libraries(test_add_resource_prefix PRIVATE Qt::Core Qt::Test)
diff --git a/tests/auto/cmake/test_add_resource_prefix/main.cpp b/tests/auto/cmake/test_add_resource_prefix/main.cpp
new file mode 100644
index 0000000000..cad519423f
--- /dev/null
+++ b/tests/auto/cmake/test_add_resource_prefix/main.cpp
@@ -0,0 +1,26 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include <QFile>
+#include <QtTest>
+
+class TestAddResourcePrefix : public QObject
+{
+    Q_OBJECT
+private slots:
+    void resourceInDefaultPathExists();
+    void resourceInGivenPathExists();
+};
+
+void TestAddResourcePrefix::resourceInDefaultPathExists()
+{
+    QVERIFY(QFile::exists(":/resource_file.txt"));
+}
+
+void TestAddResourcePrefix::resourceInGivenPathExists()
+{
+    QVERIFY(QFile::exists(":/resources/resource_file.txt"));
+}
+
+QTEST_MAIN(TestAddResourcePrefix)
+#include "main.moc"
diff --git a/tests/auto/cmake/test_add_resource_prefix/resource_file.txt b/tests/auto/cmake/test_add_resource_prefix/resource_file.txt
new file mode 100644
index 0000000000..2c604a4f18
--- /dev/null
+++ b/tests/auto/cmake/test_add_resource_prefix/resource_file.txt
@@ -0,0 +1 @@
+Ken sent me.