Bug #22194: File.realpath and File.realdirpath handle differently path encoding incompatible with a filesystem's one

• Status: Open
• Assignee: -
• Target version: -
• Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN

[andrykonchin (Andrew Konchin)]

Both realpath and realdirpath methods accept a path parameter and try to return result in the path's encoding.

realpath:

File.realpath(".rubocop.yml").encoding # => #<Encoding:UTF-8>
File.realpath(".rubocop.yml".encode("US-ASCII")).encoding # => #<Encoding:US-ASCII>

realdirpath:

File.realdirpath("src").encoding # => #<Encoding:UTF-8>
File.realdirpath("src".encode("US-ASCII")).encoding # => #<Encoding:US-ASCII>

But it's possible that path's encoding isn't compatible with the filesystem's one (that's is common to be UTF-8 on Linux and macOS), that's converting from the filesystem's encoding to path's encoding fails.

In this case realpath and realdirpath behaves differently - realpath just "forces" encoding to path's one (and as fallback to filesystem's and then to binary if a string becomes broken) and realdirpath just skips this encoding and returns a string as is in the filesystem's encoding.

realpath:

File.realpath(".".encode(Encoding::ISO_8859_1), "test_dir_🦊").encoding # => #<Encoding:ISO-8859-1>

realdirpath:

File.realdirpath(".".encode(Encoding::ISO_8859_1), "test_dir_🦊").encoding # => #<Encoding:UTF-8>

It makes sense for the methods to handle this edge case consistently.

[andrykonchin (Andrew Konchin)]

• Subject changed from File.realpath and File.realdirpath handle differently path encoding incompatible to a filesystem's one to File.realpath and File.realdirpath handle differently path encoding incompatible with a filesystem's one

[andrykonchin (Andrew Konchin)]

• Description updated (diff)

[andrykonchin (Andrew Konchin)]

• Description updated (diff)

[sophiathedev (Nguyen Thang)]

I've submitted a PR to fix this issue here:
https://github.com/ruby/ruby/pull/17981

Thank you @andrykonchin (Andrew Konchin) for the bug report and the helpful notes! 🐐

Any feedback on the PR is highly appreciated.