cabal build does not work, despite having happy-1.20 in PATH

[sgraf812]

Here's a log of my attempt to build happy on abcd8c0:

$ cabal --version
cabal-install version 3.10.2.1
compiled using version 3.10.2.1 of the Cabal library
$ cabal build
Resolving dependencies...
Build profile: -w ghc-9.4.7 -O1
In order, the following will be built (use -v for more details):
 - happy-codegen-common-2.0 (lib) (first run)
 - happy-grammar-2.0 (lib) (first run)
 - happy-tabular-2.0 (lib) (first run)
 - happy-frontend-2.0 (lib) (first run)
 - happy-backend-lalr-2.0 (lib) (first run)
 - happy-backend-glr-2.0 (lib) (first run)
 - happy-2.0 (exe:happy) (first run)
Configuring library for happy-codegen-common-2.0..
Configuring library for happy-grammar-2.0..
Preprocessing library for happy-grammar-2.0..
Building library for happy-grammar-2.0..
Preprocessing library for happy-codegen-common-2.0..
Building library for happy-codegen-common-2.0..
[1 of 1] Compiling Happy.Grammar    ( src/Happy/Grammar.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-grammar-2.0/build/Happy/Grammar.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-grammar-2.0/build/Happy/Grammar.dyn_o )
[1 of 1] Compiling Happy.CodeGen.Common.Options ( src/Happy/CodeGen/Common/Options.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-codegen-common-2.0/build/Happy/CodeGen/Common/Options.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-codegen-common-2.0/build/Happy/CodeGen/Common/Options.dyn_o )
Configuring library for happy-tabular-2.0..
Configuring library for happy-frontend-2.0..
Preprocessing library for happy-tabular-2.0..
Building library for happy-tabular-2.0..
Preprocessing library for happy-frontend-2.0..
happy: /evo/code/hs/happy/././HappyTemplate-arrays-coerce: openFile: does not exist (No such file or directory)
[1 of 5] Compiling Happy.Tabular.NameSet ( src/Happy/Tabular/NameSet.hs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/NameSet.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/NameSet.dyn_o )
[2 of 5] Compiling Happy.Tabular.First ( src/Happy/Tabular/First.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/First.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/First.dyn_o )
[3 of 5] Compiling Happy.Tabular.LALR ( src/Happy/Tabular/LALR.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/LALR.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/LALR.dyn_o )

src/Happy/Tabular/LALR.lhs:290:9: warning: [-Wincomplete-uni-patterns]
    Pattern match(es) are non-exhaustive
    In a pattern binding:
        Patterns of type ‘(Int, [[(Name, Int)]],
                           [Set Lr0Item])’ not matched:
            (_, [], _)
            (_, ((_:_):_), _)
    |
290 | >       (_, ([]:intgotos), newNewSets) =
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...

src/Happy/Tabular/LALR.lhs:438:12: warning: [-Wincomplete-uni-patterns]
    Pattern match(es) are non-exhaustive
    In a lambda abstraction:
        Patterns of type ‘[((Int, Lr0Item), NameSet.IntSet)]’ not matched:
            []
    |
438 | >     map (\cs@(((a,b),_):_) -> (a,b,NameSet.unions $ map snd cs)) .
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[4 of 5] Compiling Happy.Tabular.Info ( src/Happy/Tabular/Info.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/Info.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular/Info.dyn_o )
[5 of 5] Compiling Happy.Tabular    ( src/Happy/Tabular.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.7/happy-tabular-2.0/build/Happy/Tabular.dyn_o )
Error: cabal: Failed to build happy-frontend-2.0 (which is required by
exe:happy from happy-2.0).

According to https://haskell-happy.readthedocs.io/en/latest/contributing.html#build-instructions, this should just work.
Apparently the build has trouble finding a generated file, /evo/code/hs/happy/././HappyTemplate-arrays-coerce. Perhaps it is looking in the wrong path, but fd -uup doesn't turn it up either.

[sgraf812]

$ runghc bootstraph.sh worked for me, but I don't see it documented (yet?). Also it pollutes git status.

[int-index]

I can't reproduce this locally. The build succeeds for me. Are you sure it's a fresh clone of the repo?

[int-index]

despite having happy-1.20 in PATH

Actually, it sounds like your happy in PATH was not installed correctly. You'd probably see a similar error trying to build other projects with it.

[sgraf812]

How strange. It works if I start a clean build in a nix-shell --pure -p ghc cabal-install happy. Nevermind then, sorry for the noise.

[sgraf812]

Actually I must take that back. Perhaps I didn't read it right back in Feb or perhaps I tried it on another machine. This is on Ubuntu 22.04:

$ nix-shell --pure -p ghc cabal-install happy
...
$ cabal build
...
[5 of 5] Compiling Happy.Tabular    ( src/Happy/Tabular.lhs, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.8/happy-tabular-2.0/build/Happy/Tabular.o, /evo/code/hs/happy/dist-newstyle/build/x86_64-linux/ghc-9.4.8/happy-tabular-2.0/build/Happy/Tabular.dyn_o )
Error: cabal: Failed to build happy-frontend-2.0 (which is required by
exe:happy from happy-2.0).

same error as in #274.

[sgraf812]

I will close this issue again in favor of #274, where Vlad already started to diagnose the error.