Deprecate QString::null

It's a Qt 3 compatibility vehicle, and as such inherits the now-alien
property to distinguish empty and null strings. Particularly worrisome
is the following asymmetry:

   QString("") == QString::null          // false
   QString("") == QString(QString::null) // true

Instead of fixing this behavior, recognize that people might use it as
a weird way to call isNull(), albeit one that once was idiomatic, and
simply deprecate everything that deals with QString::null.

[ChangeLog][QtCore][QString] QString::null is now deprecated. When
used to construct a QString, use QString() instead. When used to
compare to a QString, replace with QString::isNull().

Change-Id: I9f7e84a92522c75666da15f49324c500ae93af42
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>

1 files changed, 5 insertions, 5 deletions

diff --git a/tests/auto/widgets/widgets/qlineedit/tst_qlineedit.cpp b/tests/auto/widgets/widgets/qlineedit/tst_qlineedit.cpp
index 4c0ffdc77c..330ce3a836 100644
--- a/tests/auto/widgets/widgets/qlineedit/tst_qlineedit.cpp
+++ b/tests/auto/widgets/widgets/qlineedit/tst_qlineedit.cpp
@@ -713,8 +713,8 @@ void tst_QLineEdit::clearInputMask()
 {
     QLineEdit *testWidget = ensureTestWidget();
     testWidget->setInputMask("000.000.000.000");
-    QVERIFY(testWidget->inputMask() != QString::null);
-    testWidget->setInputMask(QString::null);
+    QVERIFY(!testWidget->inputMask().isNull());
+    testWidget->setInputMask(QString());
     QCOMPARE(testWidget->inputMask(), QString());
 }
 
@@ -2277,7 +2277,7 @@ void tst_QLineEdit::textChangedAndTextEdited()
 
     changed_count = 0;
     edited_count = 0;
-    changed_string = QString::null;
+    changed_string.clear();
 
     testWidget->setText("foo");
     QCOMPARE(changed_count, 1);
@@ -2286,7 +2286,7 @@ void tst_QLineEdit::textChangedAndTextEdited()
 
     changed_count = 0;
     edited_count = 0;
-    changed_string = QString::null;
+    changed_string.clear();
 
     testWidget->setText("");
     QCOMPARE(changed_count, 1);
@@ -3108,7 +3108,7 @@ void tst_QLineEdit::maxLengthAndInputMask()
     QVERIFY(testWidget->inputMask().isNull());
     testWidget->setMaxLength(10);
     QCOMPARE(testWidget->maxLength(), 10);
-    testWidget->setInputMask(QString::null);
+    testWidget->setInputMask(QString());
     QVERIFY(testWidget->inputMask().isNull());
     QCOMPARE(testWidget->maxLength(), 10);
 }