Cannot build happy 2.x from hackage

[avdv]

Describe the bug
After updating the stackage snapshot to 2024-10-10, we get happy version 2.0.2 from hackage.

This version is no longer a simple executable but the package has been split into the command line tool and a library with multiple sublibraries.

First off, this means we have to declare dependencies between components of the library manually:

stack_snapshot(
     name = "stackage",
     components = { 
         "happy-lib": [                                                                                                                                                      
            "lib",                                                                                                                                                          
            "lib:grammar",                                                                                                                                                  
            "lib:backend-glr",                                                                                                                                              
            "lib:backend-lalr",                                                                                                                                             
            "lib:frontend",                                                                                                                                                 
            "lib:tabular",                                                                                                                                                  
        ],                                                                                                                                                                  
     },
     components_dependencies = {
        "happy-lib": repr({                                                                                                                                                 
            "lib:backend-glr": ["lib:grammar", "lib:tabular"],                                                                                                              
            "lib:backend-lalr": ["lib:grammar", "lib:tabular"],                                                                                                             
            "lib:frontend": ["lib:grammar"],                                                                                                                                
            "lib:happy-lib": ["lib:grammar", "lib:backend-glr", "lib:backend-lalr", "lib:frontend", "lib:tabular"],                                                         
            "lib:tabular": ["lib:grammar"],                                                                                                                                 
        }),                                                                                                                                                                 
     },
   ...
)

Next, the problem is that the happy-lib component is basically empty (ie. it does not produce a static nor shared library and no haddock) since it just re-exports modules from sub-libraries.

Furthermore, the backend sublibraries depend on the Paths_happy_lib module (see here) to locate its data-dir which fails at runtime since the location of the data-dir in the runfiles tree is completely different to what the Cabal generated (relocatable) Paths modules expects:

happy: /home/claudio/.cache/bazel/_bazel_claudio/f3d395587a4c32cd78e0bbc3318c2a29/execroot/rules_haskell_tests/bazel-out/k8-opt-exec-C7777A24/bin/external/stackage/happy-2.0.2/_install/happy-lib-2.0.2-backend-lalr_data/HappyTemplate.hs: openFile: does not exist (No such file or directory)

We would need to pass generate_paths_module = True to the haskell_cabal_libary stanzas generated by stack_snapshot. But that would also require patching the .cabal file to disable auto-generation of the Paths modules and add the runfiles library as a dependency. Probably the best option would be to vendor the sources in this case.

To Reproduce
Use stack_snapshot with happy >= 2 and try to run it as a tool.

Expected behavior
We should be able to build happy (and happy-lib).

Environment

• OS name + version: linux / nixOS
• Bazel version: 6.5.0
• Version of the rules: 1.0.0

Additional context
Add any other context about the problem here.