happy: fix for justStaticExecutables

[ryota2357]

Things done

Remove references to happy-lib path so that happy can build on aarch64-darwin.

See: #304352
ZHF: #457852

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

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[ryota2357]

I tested basic functionality with:

Calc.y

{
module Main where
import Data.Char (isDigit, isSpace)
}

%name calc
%tokentype { Token }
%error { parseError }
%token
    int     { TokenInt $$ }
    '+'     { TokenPlus }

%%

Exp : Exp '+' int    { $1 + $3 }
    | int            { $1 }

{
data Token
      = TokenInt Int
      | TokenPlus
      deriving Show

lexer :: String -> [Token]
lexer [] = []
lexer (c:cs)
    | isSpace c = lexer cs
    | isDigit c = lexerNum (c:cs)
    | c == '+'  = TokenPlus : lexer cs
    | otherwise = error $ "Unknown character: " ++ [c]

lexerNum :: String -> [Token]
lexerNum cs = TokenInt (read num) : lexer rest
  where (num,rest) = span isDigit cs

parseError :: [Token] -> a
parseError _ = error "Parse error"

main :: IO ()
main = do
    let input = "10 + 20 + 30"
    print $ "Input: " ++ input
    print $ "Result: " ++ show (calc (lexer input))
}

$ ./result/bin/happy Calc.y
Warning: With happy 2.0, the --ghc flag has become non-optional. To suppress this warning, pass the --ghc flag.

$ nix run nixpkgs#ghc -- Calc.hs -o calc
[1 of 2] Compiling Main             ( Calc.hs, Calc.o )
[2 of 2] Linking calc

$ ./calc
"Input: 10 + 20 + 30"
"Result: 60"

[ryota2357]

I created #463650, which avoids the need for many package rebuilds.
Which is the better way to fix the happy build error?

[sternenseemann]

I prefer this being fixed globally. There is time to get this into a staging cycle for 25.11, so no need to rush a worse version of this fix to master. We'll need to check whether the current staging branch will reach 25.11 or we'll need to backport.

Checked that happy(-lib) only use version and getDataDir.

[ryota2357]

@sternenseemann
Thank you for the review and for answering my question!
I've fixed it.

[wolfgangwalther]

There is time to get this into a staging cycle for 25.11, so no need to rush a worse version of this fix to master. We'll need to check whether the current staging branch will reach 25.11 or we'll need to backport.

We already had staging branch-off, so if this should go into 25.11, we need to backport it to staging-25.11.

[nixpkgs-ci]

Successfully created backport PR for staging-25.11:

• [Backport staging-25.11] happy: fix for justStaticExecutables #463718