ShouldBeUnique does not always prevent duplicate jobs

[liamkeily]

I am using ShouldBeUnique on Jobs in a project and noticed that duplicate jobs are still being queued. On investigation it appears that ShouldBeUnique only works if you dispatch a job in certain ways.

I have put together a test to prove the various behaviours of ShouldBeUnique liamkeily/laravel-queue-behaviour@ff34c3e#diff-88de2e685736b4d69dd9ac122767ca9580e3feb74cc821bc1f109accb2ea9017

To summarise:

1. The dispatch helper works correctly and prevents duplicate jobs
2. Bus::dispatch ignores it and allows duplicate jobs
3. Bus::batch ignores it and allows duplicate jobs
4. Bus::chain removes duplicates in an individual chain, but allows another chain to add duplicates

I'm not sure if this is considered a bug or expected behaviour, but it seems confusing so opening as a discussion for thoughts.

[chrisrickard]

Yup, same issue... turns out it's expected behaviour