Stack does not file-watch dependencies anymore

[NorfairKing]

Steps to reproduce

Make a project with two packages: a and b where b is a dependency of a.
Start stack install --file-watch a.
Make a change in b.

This is also broken for intra-package dependencies.
For example when the executable of package a depends on the library of package a.

Expected

A rebuild

Actual

No rebuild

Stack version

stack --version
2.5.1 x86_64 hpack-0.34.2

Method of installation

• nixpkgs

[NorfairKing]

Workaround: stack install a b --file-watch

[NorfairKing]

It looks like this was intentional; #5310 cc @qrilka who made that change.
I'm not entirely sure whether this change was entirely intentional because watching dependencies (especially within the same package) seems like a good default while watching unrelated packages does not seem like a good default.

In any case, another work around based on that issue: stack install a --file-watch --watch-all.

[qrilka]

@NorfairKing I suppose that you want to have dependencies taken into consideration for file watching. In principle that wasn't available before #5317 but every local file was watched so it looked like it was. That option is still available with --watch-all. Adding files from local dependencies into watch list requires a new PR.

[dten]

@NorfairKing My intention with #5317 was just to not watch watch files from unrelated packages / components. I just got round to upgrading and it seems it didn't quite work out how I imagined it would😅

[qrilka]

@dten please raise your concerns if you think that #5317 results in some unexpected behavior

[dten]

Hey yea so my actual life project has a structure roughly like this

stack.yaml
  - project webhost
    - webhost-lib
    - webhost-executable
      - dep: webhost
      - dep: common_stuff
  - project tester
    - tester-lib
    - tester-tests
      - dep: tester
      - dep: common_stuff
  - project common_stuff
    - common_stuff-lib

the webhost runs and is auto reloaded by yesod-bin
then (in another stack-work) the tester project can run tests against the running host

before #5317 watch building the webhost would watch all libs, which meant that changing the common lib would cause a rebuild (desirable) but also changing the test lib would cause a rebuild (undesirable).

it seems now that only the webhost lib is watched, so changing the common stuff does not result in rebuilding (undesirable)

my intention was that since common_stuff-lib is part of the local dependencies of the build target(s) then it should also be watched, but since tester-lib is not then it should not.

[dten]

please note I also mean if common_stuff-lib had local deps they would also be watched etc

[qrilka]

Yeah @dten it looks like you want package dependencies taken into consideration - that makes sense. I will try to find some time to look into it. It doesn't look to be a hard one.

[dten]

awesome thanks

[dten]

I take it this is on the back burner?

[qrilka]

Unfortunately yes - to implement this we need to construct extra dependency graph and I didn't find time to work on this

[dten]

is this something I might be able to do with some guidance ?

[qrilka]

That would be great but unfortunately will be mostly away on my vacation for the next 2 weeks so if you want we could restart this discussion somewhere around the 1st of August. Thanks