Internal error when a file is not accessible by the user

[Grillo-0]

Description

Steps to Reproduce the Problem

1. mkdir test && cd test
2. jj git init
3. echo aaaaa | sudo tee foo > /dev/null
4. sudo chmod go-rwx foo
5. sudo touch foo
6. jj

Expected Behavior

Run default command

Actual Behavior

Hint: Use `jj -h` for a list of available commands.
Run `jj config set --user ui.default-command log` to disable this message.
Internal error: Failed to snapshot the working copy
Caused by:
1: Failed to open file /tmp/test/foo
2: Permission denied (os error 13)

Specifications

• Platform: Linux
• Version: acdc42f ("doc: add comment to explain the syntax of folded examples")

[yuja]

Perhaps, the expected behavior is a better error message with a hint for --ignore-working-copy. If we add snapshot warning, permission errors might be turned into warning, but I'm not sure.