robert-hooke
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technomancy
Ordering is not guaranteed on hook execution
I expected hooks to wrap each other (i.e., to be executed in the opposite order that they were added). They don't - because they're added to a hash-map, they are executed in whichever order 'vals' returns them in. It would be useful to use a map instead that remembered insertion order and work in reverse to get this behavior.
I sort of agree, but part of using hooks is that you are asserting control over something you don't normally control. This means you need to write your hook in a way that works without assumptions around order.
That said, this isn't always feasible, and I'd accept a patch to change it to preseve insertion order.
I'll see if I can come up with one.
As an aside, the context this came up in was using lein-package, where I had the default lein-package hook installed that intercepts lein's install and deploy stuff. In my case, I wanted to apply my hook around that in a certain scope-limited context, but found their hook was still being called first.
This issue should probably be closed in light of https://github.com/technomancy/robert-hooke/pull/21#issuecomment-102785184, though perhaps we ought to have documentation about intended usage so the issue doesn't pop back up periodically.
We've hit this issue at CircleCI when testing for upgrades to Clojure 1.7 (which changes the sort order or hashes).
