would you remove skip from the test and add test case commit from #4593 to ensure it is fixed?

It will still fail because I didn't integrate locale into format integer with numeric option... But if you want to remove it to test whether it is panic, I will do it!

you can replace skip with expectedFailure in that case. At least we can test if it is crash or not.

rerunning CI with #4593

Could you check the test result? new code seems generating malformatted string.

---- format::tests::test_format_int_sep stdout ----
thread 'format::tests::test_format_int_sep' panicked at 'assertion failed: `(left == right)`
  left: `Ok("0000001234567,890,123,456,789,012,345,678")`,
 right: `Ok("1,234,567,890,123,456,789,012,345,678")`', common/src/format.rs:1035:9