Bogus warnings about system search path on v2 commands

[fgaz]

> cabal install --lib <package>
Warning: The directory
<store path>/bin
is not in the system search path.

The same happens with v2-build and other v2-commands.
Note that we are not trying to cabal-install (as in v2-install exes) anything. This happens whenever an exe gets Cabal-installed (as in runhaskell Cabal.hs install) in the store.
I remember this not happening before.

This is cabal 3.0.0.0 with ghc 8.6.5 on nixos

[phadej]

That would be easy to fix if we #6481, i.e. rather then adding even more conditionals in v2-install, let us separate the functionality.

[fgaz]

this is a problem in all v2 commands

[andreasabel]

I have

installdir: /Users/abel/.cabal/bin
install-method: copy

where the installdir is in the PATH, but when I v2-install anything, I get this bogus warning:

$ cabal install dhall
...
Building executable 'dhall' for dhall-1.37.1..
[1 of 1] Compiling Main             ( dhall/Main.hs, dist/build/dhall/dhall-tmp/Main.o )
Linking dist/build/dhall/dhall ...
Installing executable dhall in /Users/abel/.cabal/store/ghc-8.10.3/incoming/new-34774/Users/abel/.cabal/store/ghc-8.10.3/dhll-1.37.1-b5c5761e/bin

Comment: not sure why cabal tells me this when I have given a different installdir.

Warning: The directory
/Users/abel/.cabal/store/ghc-8.10.3/incoming/new-34774/Users/abel/.cabal/store/ghc-8.10.3/dhll-1.37.1-b5c5761e/bin
is not in the system search path.

Comment: I would never construct such a convoluted path, nor put it in my system search path. This warning seems to be bogus without exception (note the incoming which clearly marks this as a temporary path).

Copying 'dhall'