Update haddocs to make use of --build-depends

[hvr]

cabal/Cabal/Distribution/Compat/Lens.hs

Lines 241 to 250 in 81a90a0

	-- First start a repl
	--
	-- > cabal new-repl Cabal:hackage-tests
	--
	-- Because @--extra-package@ isn't yet implemented, we use a test-suite
	-- with @generics-sop@ dependency.
	--
	-- In the repl, we load a helper script:
	--
	-- > :l ../generics-sop-lens.hs

Starting with cabal 2.4, I'd expect this (IOW, I haven't tested this) to be replaceable with

cabal v2-repl -b generics-sop lib:Cabal

being invoked inside the cabal.project-scope

cc @phadej @typedrat

[ulysses4ever]

The haddocks under question live here these days:

cabal/Cabal-syntax/src/Distribution/Compat/Lens.hs

Lines 239 to 248 in 5159ffb

	-- First start a repl
	--
	-- > cabal new-repl Cabal-tests:hackage-tests
	--
	-- Because @--extra-package@ isn't yet implemented, we use a test-suite
	-- with @generics-sop@ dependency.
	--
	-- In the repl, we load a helper script:
	--
	-- > :l ../generics-sop-lens.hs

The proposed change (using -b) is a valid one, in theory, but it doesn't work due to #6859. Even worse, the existing recipe doesn't work anymore because Cabal-tests:hackage-tests does not depend on generics-sop anymore:

cabal/Cabal-tests/Cabal-tests.cabal

Lines 140 to 164 in 5159ffb

	test-suite hackage-tests
	type: exitcode-stdio-1.0
	main-is: HackageTests.hs
	hs-source-dirs: tests
	build-depends:
	base
	, bytestring
	, Cabal
	, Cabal-syntax
	, Cabal-tree-diff
	, containers
	, deepseq
	, directory
	, filepath
	build-depends:
	base-compat >=0.11.0 && <0.13
	, base-orphans >=0.6 && <0.9
	, clock >=0.8 && <0.9
	, optparse-applicative >=0.13.2.0 && <0.17
	, stm >=2.4.5.0 && <2.6
	, tar >=0.5.0.3 && <0.6
	, tree-diff >=0.1 && <0.3

So I'm having hard time figuring how to improve the current state. A radical thought would be to remove the comment (and generics-sop-lens.hs) altogether, if no one really uses it. Another option is to move it to the wiki. Any other thoughts?

[Mikolaj]

I'd say, if the tooling in question is in flux and no set finish date, let's remove the comment. Nothing worse than incorrect docs.