Ensure we recompile protocols on IEx.Helpers.recompile

[josevalim]

[emilsoman]

@josevalim this bit me too. I spent some time yesterday debugging this.
Here's what I found:

Step 1. Create an app with a protocol and compile for the first time -> works as expected
Step 2. Change the protocol and compile again -> compiles fine, but function in protocol not dispatched properly.

I think the problem is that we don't check for stale protocols, instead currently only additions or removals result in fresh consolidation. I tried to see if I can put together a fix that checks if protocol files become stale compared to the protocol manifest in order to mark them for consolidation.

Here's the code that I have so far : emilsoman@223b809 . Please let me know if this is in the right direction.

[josevalim]

@emilsoman I think we should be able to simply call "compile.protocols" inside the recompile task. Have you tried this approach? Also, can you provide a repo that reproduces the issue? :) It will make it easier for us to verify a fix. Thank you!

[emilsoman]

@josevalim Here's a repository which demonstrates the issue : https://github.com/emilsoman/protocol_recompile .

Please note that I'm using the master branch of Elixir. Steps to reproduce are mentioned on the README. Thanks :)

[emilsoman]

@josevalim were you able to reproduce the issue ?

[josevalim]

Sorry, I didn't try it yet! I will do once i am back to tackling issues.

[danhper]

I managed to reproduce the issue here, but I did not find a solution yet.
Calling compile.protocols does not work, as Mix.Utils.stale? seems to return false,
and the manifest itself is not changed, as it does not contain information about
the name of the functions in the protocol.
I will try to check why stale? is returning false when I have a moment.

[emilsoman]

I was preparing a fix for this. Can you check this comment above : #4151 (comment)