Say what GHC version is being using for the build?

[philderbeast]

I'm comparing stack and cabal output building the same hlint-plugin project and noticed cabal is very clear about which GHC version it is using with its Build profile: -w ghc-9.0.2 -O1 but I have to visually scan path elements of the install path to see this for stack.

$ stack --version
Version 2.13.1, Git revision 8102bb8afce90fc954f48efae38b87f37cabc988 x86_64 hpack-0.36.0

$ cabal --version
cabal-install version 3.11.0.0
compiled using version 3.11.0.0 of the Cabal library

$ stack build --test --no-run-tests

Warning: WARNING: This stack project is generated.
hlint-plugin> configure (lib)
Configuring hlint-plugin-1.0.2...
hlint-plugin> build (lib)
Preprocessing library for hlint-plugin-1.0.2..
Building library for hlint-plugin-1.0.2..
[1 of 2] Compiling HLint.Plugin.Settings
[2 of 2] Compiling HLint.Plugin
hlint-plugin> copy/register
Installing library in /.../hlint-plugin/.stack-work/install/x86_64-linux
   /77e1e65734194babbef5a670a7fffc8ad1833c81e4c13562134c9a797b54872d
   /9.0.2/lib/x86_64-linux-ghc-9.0.2/hlint-plugin-1.0.2-JOPnvvxdmWa2Izg7q332qw
Registering library for hlint-plugin-1.0.2..

$ cabal build all --enable-tests
Resolving dependencies...
Build profile: -w ghc-9.0.2 -O1
In order, the following will be built (use -v for more details):
 - hlint-plugin-1.0.2 (lib) (first run)
Configuring library for hlint-plugin-1.0.2...
Preprocessing library for hlint-plugin-1.0.2...
Building library for hlint-plugin-1.0.2...
[1 of 2] Compiling HLint.Plugin.Settings
[2 of 2] Compiling HLint.Plugin

Could we please have stack say what GHC version is being using for the build?

[mpilgrem]

This info is already provided as a debug level message, so a solution may be to elevate that same report to an info level message.

[philderbeast]

If I run with --verbose or --verbosity=debug then I don't easily see the compiler version in the output but it is there in paths. I don't see one single message we could elevate to the info level that would be suitable.

$ ~/.local/bin/stack build --test --no-run-tests --verbose
...
$ ~/.local/bin/stack build --test --no-run-tests --verbosity=debug

If I run with --cabal-verbose then I do see the compiler version but mixed in with a lot of other output detail.

$ ~/.local/bin/stack build --test --no-run-tests --cabal-verbose
hlint-plugin> configure (lib)
...
Dependency ghc ==9.0.2: using ghc-9.0.2
...
Configured component graph:
    component hlint-plugin-1.0.2-JOPnvvxdmWa2Izg7q332qw
...
        include ghc-9.0.2
...
Linked component graph:
    unit hlint-plugin-1.0.2-JOPnvvxdmWa2Izg7q332qw
...
        include ghc-9.0.2
...
Ready component graph:
    definite hlint-plugin-1.0.2-JOPnvvxdmWa2Izg7q332qw
...
        depends ghc-9.0.2
...
Using Cabal-3.4.1.0 compiled by ghc-9.0
Using compiler: ghc-9.0.2
...
Using ghc version 9.0.2 given by user at:
~/.ghcup/ghc/9.0.2/bin/ghc-9.0.2
Using ghc-pkg version 9.0.2 given by user at:
~/.ghcup/ghc/9.0.2/bin/ghc-pkg-9.0.2
...
Using haddock version 2.25.1 found on system at:
~/.ghcup/ghc/9.0.2/bin/haddock-ghc-9.0.2
...
Using runghc version 9.0.2 found on system at:
~/.ghcup/ghc/9.0.2/bin/runghc-9.0.2
...

[mpilgrem]

@philderbeast, sorry to send you on a wild goose chase - I was misremembering - and I've also realised that you only want Stack to report the GHC version used for stack build and not other commands that use a Stack environment.

[mpilgrem]

#6344 now merged.