Can't test a locally built CHaP with a small test project consisting of just a cabal.project file

[koslambrou]

Followed the instructions in the "... by building packages with cabal" section: https://github.com/IntersectMBO/cardano-haskell-packages?tab=readme-ov-file#-by-building-packages-with-cabal

My cabal.project is:

-- Give it a different name to avoid cabal confusing it with the
-- real CHaP
repository cardano-haskell-packages-local
  -- Point this to the *built* repository
  url: file:/home/kolam/git/iog/cardano-haskell-packages/_repo
  secure: True
  -- You can skip the root-keys field

-- Add all the packages you want to try building
extra-packages:
  , cardano-testnet-8.8.0

The root folder only has this single cabal.project file.

Then, doing cabal update as instructed, I get:

$ cabal update
Warning: There are no packages or optional-packages in the project
open: does not exist (No such file or directory)

[andreabedini]

Ah yes, this must be that annoying bug of cabal where it tries to create a file before creating the directory the file is supposed to be. Try

mkdir ~/.cabal/packages/cardano-haskell-packages-local

(or equivalent).