Use qt.qml.states logging category instead of STATECHANGE_DEBUG env

- It should not be a warning: it's for debugging.
- It's nice to have the logging category instead of "default" in case
  you have %{category} in your QT_MESSAGE_PATTERN.
- The env var didn't even have QT or QML in it.

[ChangeLog][QtQml] The new qt.qml.states logging category is useful
for debugging states and transitions. It replaces the STATECHANGE_DEBUG
environment variable.

Task-number: QTBUG-100117
Pick-to: 6.3
Change-Id: If67e21488a66867645f3a395941fcc92d3ea7bbb
Reviewed-by: Ulf Hermann <[email protected]>

1 files changed, 6 insertions, 7 deletions

diff --git a/src/quick/util/qquickstategroup.cpp b/src/quick/util/qquickstategroup.cpp
index b86333943c..d664b67485 100644
--- a/src/quick/util/qquickstategroup.cpp
+++ b/src/quick/util/qquickstategroup.cpp
@@ -53,7 +53,7 @@
 
 QT_BEGIN_NAMESPACE
 
-DEFINE_BOOL_CONFIG_OPTION(stateChangeDebug, STATECHANGE_DEBUG);
+Q_DECLARE_LOGGING_CATEGORY(lcStates)
 
 class QQuickStateGroupPrivate : public QObjectPrivate
 {
@@ -377,8 +377,7 @@ bool QQuickStateGroupPrivate::updateAutoState()
         if (state->isWhenKnown()) {
             if (state->isNamed()) {
                 if (state->when()) {
-                    if (stateChangeDebug())
-                        qWarning() << "Setting auto state due to expression";
+                    qCDebug(lcStates) << "Setting auto state due to expression";
                     if (currentState != state->name()) {
                         q->setState(state->name());
                         return true;
@@ -483,11 +482,11 @@ void QQuickStateGroupPrivate::setCurrentStateInternal(const QString &state,
     applyingState = true;
 
     QQuickTransition *transition = ignoreTrans ? nullptr : findTransition(currentState, state);
-    if (stateChangeDebug()) {
-        qWarning() << this << "Changing state.  From" << currentState << ". To" << state;
+    if (lcStates().isDebugEnabled()) {
+        qCDebug(lcStates) << this << "changing state from:" << currentState << "to:" << state;
         if (transition)
-            qWarning() << "   using transition" << transition->fromState()
-                       << transition->toState();
+            qCDebug(lcStates) << "   using transition" << transition->fromState()
+                              << transition->toState();
     }
 
     QQuickState *oldState = nullptr;