From f638c9fa317eeb2085249238d95996e783a1c891 Mon Sep 17 00:00:00 2001
From: Erik Verbruggen <erik@verbruggen.consulting>
Date: Fri, 24 Jan 2025 14:18:04 +0100
Subject: [PATCH] Use `std::filesystem::rename` on non-Windows systems

To prevent `QFile::rename` doing normalization changes to the file name.
---
 src/common/filesystembase.cpp | 23 +++++-----------------
 test/testfilesystem.cpp       | 37 +++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 18 deletions(-)

diff --git a/src/common/filesystembase.cpp b/src/common/filesystembase.cpp
index 835c37c7fbc..193b44d9c82 100644
--- a/src/common/filesystembase.cpp
+++ b/src/common/filesystembase.cpp
@@ -209,28 +209,15 @@ bool FileSystem::uncheckedRenameReplace(const QString &originFileName,
     QString *errorString)
 {
     Q_ASSERT(errorString);
+
 #ifndef Q_OS_WIN
-    bool success;
-    QFile orig(originFileName);
-    // We want a rename that also overwrites.  QFile::rename does not overwrite.
-    // Qt 5.1 has QSaveFile::renameOverwrite we could use.
-    // ### FIXME
-    success = true;
-    bool destExists = fileExists(destinationFileName);
-    if (destExists && !QFile::remove(destinationFileName)) {
-        *errorString = orig.errorString();
-        qCWarning(lcFileSystem) << "Target file could not be removed.";
-        success = false;
-    }
-    if (success) {
-        success = orig.rename(destinationFileName);
-    }
-    if (!success) {
-        *errorString = orig.errorString();
+    std::error_code err;
+    std::filesystem::rename(originFileName.toStdString(), destinationFileName.toStdString(), err);
+    if (err) {
+        *errorString = QString::fromStdString(err.message());
         qCWarning(lcFileSystem) << "Renaming temp file to final failed: " << *errorString;
         return false;
     }
-
 #else //Q_OS_WIN
     // You can not overwrite a read-only file on windows.
 
diff --git a/test/testfilesystem.cpp b/test/testfilesystem.cpp
index 097bcb4e1a9..e2fb5da7659 100644
--- a/test/testfilesystem.cpp
+++ b/test/testfilesystem.cpp
@@ -168,6 +168,43 @@ private Q_SLOTS:
         }
         csync_vio_local_closedir(dh);
     }
+
+    void testRename_data()
+    {
+        QTest::addColumn<QString>("name");
+
+        const unsigned char a_umlaut_composed_bytes[] = {0xc3, 0xa4, 0x00};
+        const QString a_umlaut_composed = QString::fromUtf8(reinterpret_cast<const char *>(a_umlaut_composed_bytes));
+        const QString a_umlaut_decomposed = a_umlaut_composed.normalized(QString::NormalizationForm_D);
+
+        QTest::newRow("a-umlaut composed") << a_umlaut_composed;
+        QTest::newRow("a-umlaut decomposed") << a_umlaut_decomposed;
+    }
+
+    // This is not a full test, it is meant to verify that no nomalization changes are done.
+    void testRename()
+    {
+        QFETCH(QString, name);
+
+        auto tmp = OCC::TestUtils::createTempDir();
+        QFile f(tmp.path() + u"/abc");
+        QVERIFY(f.open(QFile::WriteOnly));
+        QByteArray data("abc");
+        QCOMPARE(f.write(data), data.size());
+        f.close();
+
+        QString err;
+        QVERIFY(OCC::FileSystem::uncheckedRenameReplace(f.fileName(), tmp.path() + u'/' + name, &err));
+
+        csync_file_stat_t buf;
+        auto dh = csync_vio_local_opendir(tmp.path());
+        QVERIFY(dh);
+        while (auto fs = csync_vio_local_readdir(dh, nullptr)) {
+            QCOMPARE(fs->path, name);
+            QCOMPARE(fs->type, ItemTypeFile);
+        }
+        csync_vio_local_closedir(dh);
+    }
 };
 
 QTEST_GUILESS_MAIN(TestFileSystem)