Detecting changes in separately located multi-project packages

[metaleap]

v1.3.2 Win64 build

(Could well be "due to GHC" or "due to Cabal" but hey it's stack I'm using as "my build tool" here ;)

A probably not entirely uncommon scenario: a package project ~/hsdev/mycorelib and an executable project ~/hsdev/myapp. The later imports/includes from the former via build-depends in .cabal plus also via

packages:
  - '.'
  - '../mycorelib'

I make a change in mycorelib, then do a stack install in myapp and voila! All gets completely rebuilt as expected, first mycorelib then all modules in myapp as the log shows (very well as they do all import a module from mycorelib).

Now. Other times --- even more often in practice --- I just make a change in mycorelib and rebuild directly in there (ie. via editor build command to do stack build just as a check for errors). If I then directly do another stack install (aka. stack build --copy-bins) in myapp it just does the well-known no-op (just copies the existing executable) even though in the developer's view the dep sources have clearly totally changed and the binary isn't up-to-date.

In the heat of the moment and especially in "multi-multi-multi-package project" , this kind of behavior is easy to miss and tricky to remember ("oooh I accidentally already built my changes in my one core/shared/common/utils library, better go my half-dozen intermediate libraries rebuilding them so the actual current project picks that up too..") --- currently one would end up having to go through all such packages rebuilding them whenever this particular failure-to-auto-propagage-changes materializes.

Unless I'm missing something? Seems like an "intuitively easy feature-turned-bug", as in "it checks the mylibcore is up to date (well its build outputs are, alright), then it checks the myapp is up to date, ah well nothing to do" --- except with mylibcore binaries / objects newer than myapp binaries / outputs, that's certainly not the case.

Or was I supposed to manually increment the mylibcore version number all the time as I'm aiming to get into the flow of heavy fast-paced iteration? ;)

[mgsloan]

Thanks for reporting the issue! I believe this is a duplicate of #2904 . I agree that this really ought to get fixed!

[metaleap]

Indeed!