Copilot code review agent fails on file paths containing spaces (autofind tab-parsing bug)

[maximaleks]

Description

The Copilot code review agent (autofind) fails with the following error when reviewing PRs that contain files in directories with spaces:

Error: Error getting common flags: diff references file 'DreamBoard/ViewControllers/2 - Power/AI/AIRootViewController.swift\t' that is not present in repo (and not marked deleted) – this often means the repository directory argument is incorrect or not the repo root

Root Cause

Git's unified diff format adds a trailing tab character (\t) after file paths in --- and +++ header lines. This is standard git behavior — the tab separates the filename from an optional timestamp.

Example from git diff | od -c:

...r   .   s   w   i   f   t   \t   \n

The autofind binary appears to include this trailing tab as part of the filename, producing AIRootViewController.swift\t instead of AIRootViewController.swift, which then fails the file-existence check.

Reproduction

1. Create a repository with a directory containing spaces, e.g. ViewControllers/2 - Power/
2. Place a Swift (or any) file inside it
3. Make a change and open a PR
4. Enable Copilot code review agent
5. The agent fails with the error above

Environment

• Repository: private iOS project
• Runner: self-hosted macOS (Apple Silicon)
• 12+ directories in the project contain spaces (legacy Xcode project structure)
• The same PR passes all other CI checks (build, test, lint, security)

Expected Behavior

autofind should strip trailing whitespace (tab/space) from filenames parsed out of unified diff headers, matching standard git diff format.

Workaround

None available on the repo side without renaming directories (breaking change for a large project). Currently the Copilot code review agent is non-functional for any PR touching files in paths with spaces.

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