Tracing re-compiled files?

[thbar]

Hello!

When I modify a Phoenix controller, in a given app this gives me:

==> transport
Compiling 14 files (.ex)

I would like to better understand why so many files are recompiled (maybe the app needs some rework to reduce that).

What is the best tool to trace that down?

Thanks!

– Thibaut

[sabiwara]

Hi! This post should provide some good pointers on how to achieve this using mix xref graph:

Speeding up re-compilation of Elixir projects - Dashbit Blog

[cblavier]

Salut @thbar

It rings a bell, check this old post:

Modifying a controller recompiles my router and all UI layer

I finally solved my problem Touching a view now recompiles only 1 file, and touching a controller recompiles 2 files (the controller and the endpoint) instead of 208 … (went from 30sec to 2sec) What did I do? watched this video twice ran a gazillion times mix xref graph --source lib/../my_controller.ex and xref graph --sink lib/../router.ex also ran fswatch _build -r | cat | grep .beam to actually see what files are being recompiled aliased RouteHelpers instead of im…

[thbar]

Thanks @sabiwara & @cblavier! I will dive into this & report back

[marcandre]

To know which files are recompiled, mix compile --verbose will list the file names.

To understand why, the the posts above help, but they predate mix xref trace as well as mix xref graph --label compile-connected.

I’d love to blog more about this.

[thbar]

@marcandre

To know which files are recompiled, mix compile --verbose will list the file names.

To understand why, the the posts above help, but they predate mix xref trace as well as mix xref graph --label compile-connected.

Thanks for those good tips Marc-André!

I now have a good idea of which files are recompiled, but even with compile-connected it’s so far not very clear why these files are related. I will have to understand that a bit further.

(but thanks for your help which moved me a bit further in the right direction).