LocalFileSystem rename fails with "No such file or directory" when source path contains hash fragment (#) on blobfuse mount

[Lyndon1994]

Bug Report

What happened

When using object_store with LocalFileSystem on a blobfuse-mounted Azure storage, file rename operations fail with "No such file or directory (os error 2)" when the source file path contains a hash fragment (#).

Environment

• object_store version: 0.12.1
• Operating System: Linux (blobfuse)
• Storage backend: Azure Blob Storage via blobfuse mount
• Related library: deltalake 1.0.1 (Python bindings)

To Reproduce

import pandas as pd
import pyarrow as pa
import tempfile
import os
from pathlib import Path

try:
df = pd.DataFrame({'x': [1, 2, 3], 'y': ['a', 'a', 'b']})
arrow_table = pa.Table.from_pandas(df)
delta_table_path = "/lakehouse/default/Tables/xy_table2"
write_deltalake(
delta_table_path,
arrow_table,
mode="overwrite",
storage_options={"mount_allow_unsafe_rename": "true"}
)
delta_table = DeltaTable(delta_table_path)
print(f"{len(delta_table.to_pandas())}")

except Exception as e:
print(f"❌ error: {e}")

Error:
❌ error: Generic LocalFileSystem error
↳ Unable to rename file
↳ No such file or directory (os error 2)

1. Mount Azure Blob Storage using blobfuse
2. Attempt to rename a file with a path containing # character
3. The rename operation fails with LocalFileSystem error

Expected behavior

File rename should succeed, or provide a more descriptive error message indicating the issue with hash fragments in paths.

Actual behavior

Generic LocalFileSystem error ↳ Unable to rename file ↳ No such file or directory (os error 2)

Additional context

This appears to be related to how blobfuse handles file paths with hash fragments. The blobfuse logs show:
Failed request, request_id: status: 404 response: {"error":{"code":"SourcePathNotFound","message":"The source path for a rename operation does not exist."}}
The source path in the blobfuse log shows a #1 suffix that seems to be causing the issue:
src = /path/to/file.parquet#1

Possible solutions

1. Add validation to reject file paths with hash fragments when using LocalFileSystem with a clear error message
2. Escape or handle hash fragments properly in file paths
3. Provide better error messaging to indicate the specific issue with path characters

Related

• This issue is related to Delta Lake operations on Azure storage via blobfuse mounts
• May be related to: Fix ObjectStore.LocalFileSystem.put_opts for blobfuse arrow-rs#5094

This issue focuses on the core problem: the object_store LocalFileSystem doesn't handle file paths with hash fragments properly when working with blobfuse mounts, and provides insufficient error messaging to diagnose the issue.

[tustvold]

Unfortunately this is a documented limitation of LocalFileSystem - https://docs.rs/object_store/0.12.0/object_store/local/struct.LocalFileSystem.html#path-semantics-1

I would recommend using the native Azure support, as an added it will likely drastically outperform blobfuse.

PRs to improve the error message are also welcome.