QFileSystemModel: respect dir filters

Given a dir A that has some files and a subdir B, when a model is set to
only show files, setting the root path to A, the filters are initially
respected. Setting the root path to B then back to A, the filters would
be ignored and B would be visible in the model.

Traversing the path elements in node() led to dir B getting added to
the bypassFilters hash table, which made filtersAcceptNode() bypass the
filters.

I couldn't find a commit explaining the logic behind using bypassFilters
(the trail goes cold at the 'Qt 4.5' mega commit). The only clue I found
was the "// always accept drives" comment in the code, which hints at
this being useful only on Windows(?).

Fixes: QTBUG-74471
Pick-to: 6.7 6.6 6.5
Change-Id: Icb9055524a28990c591e924634a63e29a49835aa
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/gui/itemmodels/qfilesystemmodel.cpp

@@ -2126,8 +2126,14 @@ void QFileSystemModelPrivate::init()
 */
 bool QFileSystemModelPrivate::filtersAcceptsNode(const QFileSystemNode *node) const
 {
+    // When the model is set to only show files, then a node representing a dir
+    // should be hidden regardless of bypassFilters.
+    // QTBUG-74471
+    const bool hideDirs = (filters & (QDir::Dirs | QDir::AllDirs)) == 0;
+    const bool shouldHideDirNode = hideDirs && node->isDir();
+
     // always accept drives
-    if (node->parent == &root || bypassFilters.contains(node))
+    if (node->parent == &root || (!shouldHideDirNode && bypassFilters.contains(node)))
         return true;
 
     // If we don't know anything yet don't accept it
@@ -2136,7 +2142,6 @@ bool QFileSystemModelPrivate::filtersAcceptsNode(const QFileSystemNode *node) co
 
     const bool filterPermissions = ((filters & QDir::PermissionMask)
                                    && (filters & QDir::PermissionMask) != QDir::PermissionMask);
-    const bool hideDirs          = !(filters & (QDir::Dirs | QDir::AllDirs));
     const bool hideFiles         = !(filters & QDir::Files);
     const bool hideReadable      = !(!filterPermissions || (filters & QDir::Readable));
     const bool hideWritable      = !(!filterPermissions || (filters & QDir::Writable));

tests/auto/gui/itemmodels/qfilesystemmodel/tst_qfilesystemmodel.cpp

@@ -29,6 +29,7 @@
 #include <algorithm>
 
 using namespace Qt::StringLiterals;
+using namespace std::chrono;
 
 #define WAITTIME 1000
 
@@ -79,6 +80,8 @@ private slots:
     void filters_data();
     void filters();
 
+    void showFilesOnly();
+
     void nameFilters();
 
     void setData_data();
@@ -675,6 +678,37 @@ void tst_QFileSystemModel::filters()
 #endif
 }
 
+void tst_QFileSystemModel::showFilesOnly()
+{
+    QString tmp = flatDirTestPath;
+    QFileSystemModel model;
+    QAbstractItemModelTester tester(&model);
+    tester.setUseFetchMore(false);
+    QVERIFY(createFiles(&model, tmp, QStringList()));
+    const QStringList files{u"a"_s, u"b"_s, u"c"_s};
+    const auto subdir = u"sub_directory"_s;
+    QVERIFY(createFiles(&model, tmp, files, 0, {subdir}));
+
+    // QTBUG-74471
+    // WHAT: setting the root path of the model to a dir with some files and a subdir
+    QModelIndex root = model.setRootPath(tmp);
+    QTRY_COMPARE(model.rowCount(root), files.size() + 1);
+
+    // Change the model to only show files
+    model.setFilter(QDir::Files);
+    QTRY_COMPARE(model.rowCount(root), files.size());
+
+    // WHEN: setting the root path to a subdir
+    QModelIndex subIndex = model.setRootPath(tmp + u'/' + subdir);
+    QTRY_COMPARE(model.rowCount(subIndex), 0);
+
+    // THEN: setting the root path to the previous (parent) dir, the model should
+    // still only show files.
+    root = model.setRootPath(tmp);
+    // Doubling the default timeout (5s) as this test to fails on macos on the CI
+    QTRY_COMPARE_WITH_TIMEOUT(model.rowCount(root), files.size(), (10s).count());
+}
+
 void tst_QFileSystemModel::nameFilters()
 {
     QStringList list;