Merge bitcoin/bitcoin#24331: util: Revert back MoveFileExW call for MinGW-w64

dc01cbc test: Add fs_tests/rename unit test (Hennadii Stepanov)
d4999d4 util: Revert back MoveFileExW call for MinGW-w64 (Hennadii Stepanov)

Pull request description:

  Unfortunately, bitcoin/bitcoin#24308 introduced a [regression](bitcoin/bitcoin#24308 (comment)) for mingw builds.

  The root of the problem is a broken implementation of [`std::filesystem::rename`](https://en.cppreference.com/w/cpp/filesystem/rename). In particular, the expected behavior
  > If `old_p` is a non-directory file, then `new_p` must be ... existing non-directory file: `new_p` _is first deleted_...

  fails with the "File exists" error.

  This PR reverts back the `MoveFileExW` call, and adds the [suggested](bitcoin/bitcoin#24308 (review)) unit test.

ACKs for top commit:
  vasild:
    ACK dc01cbc

Tree-SHA512: c8e5a98844cfa32bec0ad67a1aaa58fe2efd0c5474d3e83490211985b110f83245758a742dcaa0a933a192ab66a7f11807e0c53ae69260b7dd02fc99f6d03849

Author: laanwj

src/test/fs_tests.cpp

@@ -118,4 +118,38 @@ BOOST_AUTO_TEST_CASE(fsbridge_fstream)
     }
 }
 
-BOOST_AUTO_TEST_SUITE_END()
+BOOST_AUTO_TEST_CASE(rename)
+{
+    const fs::path tmpfolder{m_args.GetDataDirBase()};
+
+    const fs::path path1{GetUniquePath(tmpfolder)};
+    const fs::path path2{GetUniquePath(tmpfolder)};
+
+    const std::string path1_contents{"1111"};
+    const std::string path2_contents{"2222"};
+
+    {
+        std::ofstream file{path1};
+        file << path1_contents;
+    }
+
+    {
+        std::ofstream file{path2};
+        file << path2_contents;
+    }
+
+    // Rename path1 -> path2.
+    BOOST_CHECK(RenameOver(path1, path2));
+
+    BOOST_CHECK(!fs::exists(path1));
+
+    {
+        std::ifstream file{path2};
+        std::string contents;
+        file >> contents;
+        BOOST_CHECK_EQUAL(contents, path1_contents);
+    }
+    fs::remove(path2);
+}
+
+BOOST_AUTO_TEST_SUITE_END()

src/util/system.cpp

@@ -1062,9 +1062,20 @@ void ArgsManager::LogArgs() const
 
 bool RenameOver(fs::path src, fs::path dest)
 {
+#ifdef __MINGW64__
+    // This is a workaround for a bug in libstdc++ which
+    // implements std::filesystem::rename with _wrename function.
+    // This bug has been fixed in upstream:
+    //  - GCC 10.3: 8dd1c1085587c9f8a21bb5e588dfe1e8cdbba79e
+    //  - GCC 11.1: 1dfd95f0a0ca1d9e6cbc00e6cbfd1fa20a98f312
+    // For more details see the commits mentioned above.
+    return MoveFileExW(src.wstring().c_str(), dest.wstring().c_str(),
+                       MOVEFILE_REPLACE_EXISTING) != 0;
+#else
     std::error_code error;
     fs::rename(src, dest, error);
     return !error;
+#endif
 }
 
 /**