QWidget: use WA_InputMethodEnabled when ImEnabled is not implemented

In Qt 6.3, a check for WA_InputMethodEnabled was removed
in QWidget, to support IM queries also for read-only
widgets (7c6e4af48). This caused a regression on iOS, which
made the input panel open for widgets that didn't support
IM at all.

A patch was merged that solved the regression (3b12305575),
but it didn't take the widget attribute into account.
Since not doing so has the potential to cause regressions,
this patch will modify the affected code once more, so that
we instead fall back to test WA_InputMethodEnabled when
ImEnabled is not implemented. This will match closely
to the way ImEnabled was implemented in Qt 6.2.

Since we, with this change, now require that either ImEnabled
or WA_InputMethodEnabled is set, our own input widgets will
fail to support IM text selection when they're read-only, since
they actually don't implement ImEnabled.
This patch will therefore also make sure that we do so.

Task-number: QTBUG-104527
Pick-to: 6.4 6.3
Change-Id: I70ad910aec38d0a74f4dd7d3115d3c45c16d2b3b
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

3 files changed, 6 insertions, 0 deletions

diff --git a/src/widgets/widgets/qlineedit.cpp b/src/widgets/widgets/qlineedit.cpp
index bd20f9963d..b87d7e09cc 100644
--- a/src/widgets/widgets/qlineedit.cpp
+++ b/src/widgets/widgets/qlineedit.cpp
@@ -1811,6 +1811,8 @@ QVariant QLineEdit::inputMethodQuery(Qt::InputMethodQuery property, QVariant arg
 {
     Q_D(const QLineEdit);
     switch(property) {
+    case Qt::ImEnabled:
+        return isEnabled();
     case Qt::ImCursorRectangle:
         return d->cursorRect();
     case Qt::ImAnchorRectangle:
diff --git a/src/widgets/widgets/qplaintextedit.cpp b/src/widgets/widgets/qplaintextedit.cpp
index 3fb8debaa5..cd9889e9ff 100644
--- a/src/widgets/widgets/qplaintextedit.cpp
+++ b/src/widgets/widgets/qplaintextedit.cpp
@@ -2206,6 +2206,8 @@ QVariant QPlainTextEdit::inputMethodQuery(Qt::InputMethodQuery query, QVariant a
 {
     Q_D(const QPlainTextEdit);
     switch (query) {
+    case Qt::ImEnabled:
+        return isEnabled();
     case Qt::ImHints:
     case Qt::ImInputItemClipRectangle:
         return QWidget::inputMethodQuery(query);
diff --git a/src/widgets/widgets/qtextedit.cpp b/src/widgets/widgets/qtextedit.cpp
index de20e0120a..b3a8963431 100644
--- a/src/widgets/widgets/qtextedit.cpp
+++ b/src/widgets/widgets/qtextedit.cpp
@@ -1803,6 +1803,8 @@ QVariant QTextEdit::inputMethodQuery(Qt::InputMethodQuery query, QVariant argume
 {
     Q_D(const QTextEdit);
     switch (query) {
+    case Qt::ImEnabled:
+        return isEnabled();
     case Qt::ImHints:
     case Qt::ImInputItemClipRectangle:
         return QWidget::inputMethodQuery(query);