[GitMonkey007]

Fixes #1863

First time contributing to this project, relatively trivial, but still a bug I think worth fixing. Discovered this issue when looking at MoveTo vs RenameAsync; I've made the relevant change and tried to adhere to the standards/contributing docs; let me know if I've missed something.

The fix itself just moves the problematic implementation details into shared methods (because they previously differ); I've added some tests again trying to adhere to the style in the project.

AI not used to write the change.

[Rob-Hague]

Thanks, I have tried to avoid understanding this part of the code in the past but the sync/async paths are clearly inconsistent, seems it was an accident in 508fc87. I've taken the liberty of combining the whole thing into a shared method. I thought about adding an integration test but it seems like it is quite hard to hit this depending on the server behaviour of SSH_FXP_REALPATH, but if you have a straightforward case then we can add it.

[Copilot]

🟡 Changes recommended

A regression test is still needed for the parent-path fallback in both GetCanonicalPath and GetCanonicalPathAsync to guard against the original full-path retry bug.

1 open issue

• Add regression tests for parent-path fallback in both canonical path methods · New

What changed in this PR

This PR addresses #1863 by aligning SSH.NET’s synchronous and asynchronous SFTP path canonicalization so failed full-path lookups fall back to resolving the parent directory.

Changes:

• Share canonicalization logic between sync and async methods.
• Correct the async fallback to resolve the parent and append the final path component.
• Avoid allocating a string for ordinal character searches in the compatibility helper.

File	Description
src/​Renci.SshNet/​Sftp/​SftpSession.cs	Unifies canonicalization logic and corrects the async parent-path fallback.
src/​Renci.SshNet/​Abstractions/​StringExtensions.cs	Optimizes ordinal character searches using IndexOf(char).

_{Review effort: Balanced}