From ce820174ee20a161570a31cdc7f945f535177efc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A5rten=20Nordheim?= <marten.nordheim@qt.io>
Date: Wed, 15 Jan 2025 14:10:41 +0100
Subject: [PATCH] QFile::rename: error out if overwrite fails when changing
 case on case-insensitive filesystems

The generic copy-and-remove fallback will first open the original file
with a different case, truncate it, and then remove the original file.
Leaving us with no file at all.

Task-number: QTBUG-132785
Pick-to: 6.8 6.5
Change-Id: Ia5a41d26c1d6d6bdc231c71acf15bd2ea496c715
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 2defca418788ab167fa1ce70e518c9250cb0909f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/io/qfile.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/corelib/io/qfile.cpp b/src/corelib/io/qfile.cpp
index 9295070dc8a..7e7c16c4660 100644
--- a/src/corelib/io/qfile.cpp
+++ b/src/corelib/io/qfile.cpp
@@ -654,6 +654,13 @@ QFile::rename(const QString &newName)
             return true;
         }
 
+        // Engine was unable to rename and the fallback will delete the original file,
+        // so we have to back out here on case-insensitive file systems:
+        if (changingCase) {
+            d->setError(QFile::RenameError, d->fileEngine->errorString());
+            return false;
+        }
+
         if (isSequential()) {
             d->setError(QFile::RenameError, tr("Will not rename sequential file using block copy"));
             return false;