$ cabal build all                                                                 47.7s  Tue 22:30
cabal: Error parsing project file /home/jule/git/hledger/cabal.project:6:
"<eitherParsec>" (line 2, column 1):
unexpected 'c'
expecting space, comma, white space or end of input

      1 packages: hledger-lib
      2           hledger
      3           hledger-ui
      4           hledger-web
      5
      6 allow-newer:
      7   brick:base
      8   config-ini:containers
      9
     10 -- generate a ghc environment file, needed by doctest
     11 -- (eg: ./.ghc.environment.x86_64-darwin-8.8.3).
     12 -- cabal 3 doesn't write these by default.
     13 -- https://github.com/simonmichael/hledger/issues/1139
     14 -- https://github.com/sol/doctest/issues/245#issuecomment-583171683
     15 -- cabal 2 doesn't understand this flag, but it's just a warning; should be ok.
     16 -- cabal 3 still fails with doctest the first time; you have to run it
     17 -- a second time. Hopefully in practice it won't fail, because of a
     18 -- preceding cabal build.
     19 write-ghc-environment-files: always