smoothscroller: always emit scrollingStopped from scrollTo

When scrollTo() is asked to move to the position the scrollbar already
holds (clamped, e.g. an item at the bottom, or a sub-pixel offset), no
animation runs and scrollingStopped() was never emitted. Callers waiting
for it stayed blocked: KItemListView::scrollToItem() delegates to scrollTo
for any non-zero offset, and DolphinView::renameSelectedItems() only opens
the inline rename editor once scrollingStopped() arrives. So inline rename
silently did nothing for the affected items.

Emit scrollingStopped() in the no-op case too, and add a regression test.

2 files changed, 71 insertions, 0 deletions

diff --git a/src/tests/CMakeLists.txt b/src/tests/CMakeLists.txt
index cac38deae..3ac657215 100644
--- a/src/tests/CMakeLists.txt
+++ b/src/tests/CMakeLists.txt
@@ -15,6 +15,9 @@ ecm_add_test(kitemsettest.cpp LINK_LIBRARIES dolphinprivate Qt6::Test)
 # KItemRangeTest
 ecm_add_test(kitemrangetest.cpp LINK_LIBRARIES dolphinprivate Qt6::Test)
 
+# KItemListSmoothScrollerTest
+ecm_add_test(kitemlistsmoothscrollertest.cpp LINK_LIBRARIES dolphinprivate Qt6::Test)
+
 
 # KItemListSelectionManagerTest
 ecm_add_test(kitemlistselectionmanagertest.cpp LINK_LIBRARIES dolphinprivate Qt6::Test)
diff --git a/src/tests/kitemlistsmoothscrollertest.cpp b/src/tests/kitemlistsmoothscrollertest.cpp
new file mode 100644
index 000000000..ac0a81d31
--- /dev/null
+++ b/src/tests/kitemlistsmoothscrollertest.cpp
@@ -0,0 +1,68 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Méven Car <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "kitemviews/private/kitemlistsmoothscroller.h"
+
+#include <QScrollBar>
+#include <QSignalSpy>
+#include <QStandardPaths>
+#include <QTest>
+
+class KItemListSmoothScrollerTest : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void initTestCase();
+    void testScrollToCurrentPositionEmitsScrollingStopped();
+    void testScrollToClampedPositionEmitsScrollingStopped();
+};
+
+void KItemListSmoothScrollerTest::initTestCase()
+{
+    QStandardPaths::setTestModeEnabled(true);
+}
+
+void KItemListSmoothScrollerTest::testScrollToCurrentPositionEmitsScrollingStopped()
+{
+    // KItemListView::scrollToItem() delegates to KItemListSmoothScroller::scrollTo()
+    // for any non-zero offset and then relies on scrollingStopped() to know when the
+    // view settled. Callers such as DolphinView::renameSelectedItems() only open the
+    // inline rename editor once scrollingStopped() arrives. If scrollTo() is asked to
+    // move to the position the scrollbar is already at, no animation runs, so it must
+    // still emit scrollingStopped() or the editor never appears.
+    QScrollBar scrollBar(Qt::Vertical);
+    scrollBar.setRange(0, 100);
+    scrollBar.setValue(50);
+
+    KItemListSmoothScroller scroller(&scrollBar);
+    QSignalSpy spy(&scroller, &KItemListSmoothScroller::scrollingStopped);
+
+    scroller.scrollTo(scrollBar.value());
+
+    QCOMPARE(spy.count(), 1);
+}
+
+void KItemListSmoothScrollerTest::testScrollToClampedPositionEmitsScrollingStopped()
+{
+    // Reproduces renaming an item at the very bottom: the scrollbar is already at its
+    // maximum, scrollToItem() still computes a non-zero offset and requests a further
+    // scroll, but the clamped target equals the current value, so nothing moves.
+    QScrollBar scrollBar(Qt::Vertical);
+    scrollBar.setRange(0, 100);
+    scrollBar.setValue(scrollBar.maximum());
+
+    KItemListSmoothScroller scroller(&scrollBar);
+    QSignalSpy spy(&scroller, &KItemListSmoothScroller::scrollingStopped);
+
+    scroller.scrollTo(scrollBar.maximum() + 50);
+
+    QCOMPARE(spy.count(), 1);
+}
+
+QTEST_MAIN(KItemListSmoothScrollerTest)
+
+#include "kitemlistsmoothscrollertest.moc"