Disk Access for App Store Apps
ABDiff is an App Store app, so it runs inside Apple’s sandbox. The sandbox prevents the app from reading files unless you explicitly grant access (for example by picking a folder, dragging files in, or adding an access root in Settings).
This is why you sometimes see a prompt like:
“ABDiff needs access to this folder to open files passed by Git.”
Why
git difftool Triggers a Disk Access Prompt
When you run git difftool, Git typically creates
temporary copies of the files it wants to compare.
These live in macOS temp folders such as:
/private/var/folders/.../T/...Those paths are outside your repo folder, so a saved
access root like /Users/you/Developer/code doesn’t apply.
ABDiff therefore asks you to approve a folder that covers the temp files
so it can open them.
If you deny the prompt, ABDiff cannot read the temp files and you’ll see errors like “No permission to read …”.
What to Do
Use one of these options:
You can review or remove saved access roots in Settings → Folder Access.
Allow the suggested folder when prompted.
ABDiff adds the chosen folder to Settings → Folder Access so it can be reused without prompting (unless you disable “Save Git access prompts here”).Add a broader access root in Settings if you use Git difftool frequently, for example:
/private/var/folders
Avoid temp paths by comparing real files inside your repo instead of
git difftool, e.g. drag the files into ABDiff.
Why It Looks Like “Whole Disk Access”
If Git passes files from different locations (e.g. one in your repo,
one in /private/var/...), the only common parent may be
/. In that case the system picker can look like “whole
disk”, but ABDiff still only reads the files you open.
ABDiff does not request Full Disk Access on its own and does not scan your drive. It only reads files and folders that you explicitly choose to open or grant access to.