What would be outside the sandbox? If you create a sandbox that only allows git diff, the I suppose you fixed this one issue, but what about everything else? If you allow the sandbox to be configurable, then how do you configure it without that just being programming?
The problem with these "microprograms" have always been that once you delegate so much, once you are willing to put in that little effort. You can't guarantee anything.
If you are willing to pull in a third party dependency to run git diff, you will never research which permissions it needs. Doing that research would be more difficult than writing the program yourself.
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What would be outside the sandbox? If you create a sandbox that only allows git diff, the I suppose you fixed this one issue, but what about everything else? If you allow the sandbox to be configurable, then how do you configure it without that just being programming?
The problem with these "microprograms" have always been that once you delegate so much, once you are willing to put in that little effort. You can't guarantee anything.
If you are willing to pull in a third party dependency to run git diff, you will never research which permissions it needs. Doing that research would be more difficult than writing the program yourself.