test(sync): cover removeRecursively sibling prefix guard

Extract the deleted directory prefix check into isPathInsideDeletedDir and
add a unit test verifying a sibling such as "A/BC" is not treated as a child
of "A/B", guarding the journal cleanup after a failed local remove.

Assisted-by: Claude Code:claude-opus-4-8

Author: camilasan

src/libsync/propagatorjobs.cpp

@@ -38,6 +38,11 @@ QByteArray localFileIdFromFullId(const QByteArray &id)
     return id.left(8);
 }
 
+bool isPathInsideDeletedDir(const QString &path, const QString &deletedDir)
+{
+    return !deletedDir.isEmpty() && path.startsWith(deletedDir + QLatin1Char('/'));
+}
+
 /**
  * The code will update the database in case of error.
  * If everything goes well (no error, returns true), the caller is responsible for removing the entries
@@ -87,7 +92,7 @@ bool PropagateLocalRemove::removeRecursively(const QString &path)
         for (const auto &it : deleted) {
             if (!it.first.startsWith(propagator()->localPath()))
                 continue;
-            if (!deletedDir.isEmpty() && it.first.startsWith(deletedDir + QLatin1Char('/')))
+            if (isPathInsideDeletedDir(it.first, deletedDir))
                 continue;
             if (it.second) {
                 deletedDir = it.first;

src/libsync/propagatorjobs.h

@@ -19,6 +19,13 @@ constexpr auto checkSumHeaderC = "OC-Checksum";
 constexpr auto contentMd5HeaderC = "Content-MD5";
 constexpr auto checksumRecalculateOnServerHeaderC = "X-Recalculate-Hash";
 
+/**
+ * Whether @p path sits inside the already removed directory @p deletedDir.
+ * Compares with a trailing slash so a sibling such as "A/BC" is not mistaken
+ * for a child of "A/B".
+ */
+[[nodiscard]] OWNCLOUDSYNC_EXPORT bool isPathInsideDeletedDir(const QString &path, const QString &deletedDir);
+
 /**
  * @brief Declaration of the other propagation jobs
  * @ingroup libsync

test/testsyncmove.cpp

@@ -13,6 +13,7 @@
 #include "common/result.h"
 #include "syncenginetestutils.h"
 #include <syncengine.h>
+#include <propagatorjobs.h>
 
 using namespace OCC;
 
@@ -1544,6 +1545,22 @@ private slots:
         QVERIFY(cleared._lockstate._lockToken.isEmpty());
         QVERIFY(!cleared._lockstate._locked);
     }
+
+    // The journal cleanup after a failed local remove must not treat a sibling as a
+    // child: "A/BC" is not inside "A/B".
+    void testDeletedDirPrefixDoesNotMatchSibling()
+    {
+        QVERIFY(isPathInsideDeletedDir(QStringLiteral("A/B/child.txt"), QStringLiteral("A/B")));
+        QVERIFY(isPathInsideDeletedDir(QStringLiteral("A/B/sub/child.txt"), QStringLiteral("A/B")));
+
+        // Sibling sharing the prefix must not be skipped.
+        QVERIFY(!isPathInsideDeletedDir(QStringLiteral("A/BC"), QStringLiteral("A/B")));
+        QVERIFY(!isPathInsideDeletedDir(QStringLiteral("A/BC/child.txt"), QStringLiteral("A/B")));
+
+        // The directory itself is not inside itself, and an empty deletedDir matches nothing.
+        QVERIFY(!isPathInsideDeletedDir(QStringLiteral("A/B"), QStringLiteral("A/B")));
+        QVERIFY(!isPathInsideDeletedDir(QStringLiteral("A/B/child.txt"), QString()));
+    }
 };
 
 QTEST_GUILESS_MAIN(TestSyncMove)