Ability to use -Wall without -Werror

[mightybyte]

I find it very useful to build with -Wall in situations where -Werror is not desirable. stack build --ghc-options="-Wall" does not display any warnings, so this does not appear to be possible right now.

[mgsloan]

The issue is probably that ghc does not rebuild when -Wall is added. Does stack build --ghc-options="-Wall -fforce-recomp" do what you want?

It may also be due to building multiple packages concurrently. In that case you need to look at build logs for warnings, or build the package individually.

[mightybyte]

It was definitely building before. -fforce-recomp didn't help either. Build logs are displayed with --pedantic, so it seems like they should be able to be displayed similarly (without taking the -j1 hit) for an option that has -Wall without -Werror.

[mgsloan]

It works for me. Can you please provide a repro based on publically available code?

Might also be worthwhile trying with HEAD stack, though I doubt that's the difference.

[mightybyte]

git clone https://github.com/jaspervdj/digestive-functors.git
cd digestive-functors
stack build --ghc-options="-Wall"

Following this by stack build --pedantic fails with warnings that weren't shown in the above -Wall build.

I'm using this version of stack:

Version 1.0.4, Git revision cf18703b1392a96a5a4896a560309e501af63260 (3220 commits) x86_64

[snoyberg]

This is most likely caused by logs for multi-package projects being sent to log files instead of to the console. If you want to see the output on the console, you need to specify just one package to build, e.g.:

stack build --ghc-options="-Wall" --file-watch digestive-functors-snap

Does that work?

[mightybyte]

That works, but it is not a sufficient solution IMO. stack build --pendantic shows warnings even when building multiple packages, so there's clearly no technical reason the same can't be done for -Wall. I want to be seeing warnings as often as possible, not just when building a single package. Getting -Wall behavior also shouldn't require any extra characters to be typed on the command line.

[mgsloan]

The reason that stack build --pedantic shows warnings for all packages is because it causes them to be errors. Erroring builds are always shown to the user.

I thoroughly agree that we should be able to show all output, and potentially even make it a default. Sounds like this is the main issue here, and it's currently tracked by #426, so marking as a dupe of that.

[mgsloan]

Might also be running into #2063

[mightybyte]

Sounds good. If #426 is the dupe for this, my main thought is that it should be possible to configure the option from the stack.yaml file so it can be set on a per-project basis rather than whenever developers think to do it.