cabal-install is seeing double -"TODO: add support for multiple packages in a directory")

[Kleidukos]

While testing 5496d39 on https://github.com/haskell-text/text-display, I get the following error:

~/Projects/text-display main                                                                                                                                                    14.08s 00:26:05
❯ find -iname "*.cabal"  
./text-display.cabal

~/Projects/text-display main                                                                                                                                                     0.09s 00:26:10
❯ /home/hecate/Contrib/cabal/dist-newstyle/build/x86_64-linux/ghc-9.4.4/cabal-install-3.9.0.0/x/cabal/build/cabal/cabal build
Warning: this is a debug build of cabal-install with assertions enabled.
Resolving dependencies...
TODO: add support for multiple packages in a directory.  Got
text-display-0.0.3.0
text-display-0.0.3.0

CallStack (from HasCallStack):
  error, called at src/Distribution/Client/ProjectOrchestration.hs:590:9 in cabal-install-3.9.0.0-inplace:Distribution.Client.ProjectOrchestration

Looks like some deduplication does not happen for some reason. I can ship a patch if it's just a matter of ordNub on the pkgids?

source: https://github.com/haskell/cabal/blob/master/cabal-install/src/Distribution/Client/ProjectOrchestration.hs#L589-L598

[fendor]

Related issues: #7395, #6197

PR that isn't properly implemented: #7396

[zzantares]

To add more color, this something that was added on #7078 it seems the idea is to actually see what packages are duplicated; alas, better instructive error messages would be great.