FR: Allow configuration of the exit code on failure

[petemounce]

If the checkout fails for some reason, that's quite likely to be a systemic failure (whether persistent like p4 being down, or transient like a network interruption on a large asset) rather than a user-level failure.

We would like to be able to set up auto-retry on BK jobs so that such failures are automatically retried, but while the exit code for such is 1 we cannot distinguish that from other user-level job failures.

We'd like to be able to specify the exit code that p4 checkouts fail with so that we can distinguish that and match it to the exit codes we use for auto-retry.

[ca-johnson]

The main thing I would suggest here really would be improving the reliability of the Perforce server - this is enterprise grade software that should not really be having transient errors.

If theres a genuine reason why such errors are expected and unavoidable, I would suggest turning on retries for 1 exitcodes in the jobs that use this plugin and instead customising the exitcodes of your user code (assuming you want to avoid retrying user errors).

This allows the problem to be solved more flexibly, for your specific case, rather than in shared code for a problem that doesn't appear to be shared.

Generally, I would be hesitant to add a configuration option, or add exit-codes specific to the sync operation since:

• This increases the complexity of code and configuration scope, making the code cost more to reason about, improve and maintain
• Most people would not need to make use of this feature - it provides no practical improvement to core functionality
• Introduces scope for bugs where some errors are not handled and given the alternative exitcode
• Difficult to test