Merge remote-tracking branch 'origin/dev' into wip/scenegraphng

Change-Id: Iea0bb0788357bc615d0e9ea411087114b8b3b720

1 files changed, 20 insertions, 0 deletions

diff --git a/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc b/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc
index f28ff5082a..99426d984d 100644
--- a/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc
+++ b/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc
@@ -179,6 +179,26 @@ Rectangle {
 Now, after the space key is pressed, the rectangle's height will continue
 auto-updating to always be three times its width.
 
+\section3 Debugging overwriting of bindings
+
+A common cause of bugs in QML applications is accidentally overwriting bindings
+with static values from JavaScript statements. To help developers track down
+problems of this kind, the QML engine is able to emit messages whenever a
+binding is lost due to imperative assignments.
+
+In order to generate such messages, you need to enable the informational output
+for the \c{qt.qml.binding.removal} logging category, for instance by calling:
+
+\code
+QLoggingCategory::setFilterRules(QStringLiteral("qt.qml.binding.removal.info=true"));
+\endcode
+
+Please refer to the QLoggingCategory documentation for more information about
+enabling output from logging categories.
+
+Note that is perfectly reasonable in some circumstances to overwrite bindings.
+Any message generated by the QML engine should be treated as a diagnostic aid,
+and not necessarily as evidence of a problem without further investigation.
 
 \section2 Using \c this with Property Binding