`nixpkgs` project version of Stack 3.7.1: Infinite <<loop>>

[NorfairKing]

General summary/comments (optional)

stack test openapi3-code-generator --verbose
3.7.1 x86_64 hpack-0.38.1
2025-12-03 10:34:15.631605: [debug] Checking for project config at: /home/syd/src/openapi-code-generator/stack.yaml
2025-12-03 10:34:15.631767: [debug] Loading project config file stack.yaml
2025-12-03 10:34:15.635853: [debug] Use of Casa server enabled: (CasaRepoPrefix "https://casa.stackage.org", 1280).
2025-12-03 10:34:15.637029: [debug] Using package location completions from a lock file
2025-12-03 10:34:15.637657: [debug] Loaded snapshot from Pantry database.
2025-12-03 10:34:15.734627: [debug] Running Hpack on /home/syd/src/openapi-code-generator/openapi3-code-generator/package.yaml
2025-12-03 10:34:15.734856: [debug] Run process within /home/syd/src/openapi-code-generator/openapi3-code-generator/: /nix/store/8dps65fsxq5wxl8srwmb8rf54d8yk3r5-hpack-0.36.1/bin/hpack
openapi3-code-generator.cabal is up-to-date
2025-12-03 10:34:15.747132: [debug] Process finished in 12ms: /nix/store/8dps65fsxq5wxl8srwmb8rf54d8yk3r5-hpack-0.36.1/bin/hpack
2025-12-03 10:34:15.747383: [debug] Prefetching git repos: []
2025-12-03 10:34:15.747419: [debug] []
2025-12-03 10:34:15.748657: [debug] Asking for a supported GHC version
2025-12-03 10:34:15.748726: [debug] Getting system compiler version
2025-12-03 10:34:15.748857: [debug] (SQL) SELECT "id","actual_version","arch","ghc_path","ghc_size","ghc_modified","ghc_pkg_path","runghc_path","haddock_path","cabal_version","global_db","global_db_cache_size","global_db_cache_modified","info","global_dump" FROM "compiler_cache" WHERE "ghc_path"=?; [PersistText "/nix/store/cjsh9jrsi3a575kza79nl2qv0l8bvny4-ghc-9.10.3-with-packages/bin/ghc-9.10.3"]
2025-12-03 10:34:15.819886: [debug] Loaded compiler information from cache
2025-12-03 10:34:15.820198: [debug] Asking for a supported GHC version
2025-12-03 10:34:15.820230: [debug] Resolving package entries
2025-12-03 10:34:15.820260: [debug] Parsing the targets
2025-12-03 10:34:15.826643: [debug] Applying and checking flags
2025-12-03 10:34:15.827759: [debug] SourceMap constructed
2025-12-03 10:34:16.160389: [error] <<loop>>

Steps to reproduce

1. git clone git@github.com:Haskell-OpenAPI-Code-Generator/Haskell-OpenAPI-Client-Code-Generator.git openapi-code-generator
2. git checkout nixos-25.11
3. stack test openapi3-code-generator --verbose

Stack version

stack --version
3.7.1 x86_64 hpack-0.38.1

Method of installation

nixpkgs

Platform

NixOS 25.05 x86_64-linux

[mpilgrem]

@NorfairKing, thanks for reporting. Starting with Windows 11, I could not reproduce with the current master branch version of Stack:

> git clone https://github.com/Haskell-OpenAPI-Code-Generator/Haskell-OpenAPI-Client-Code-Generator.git
> cd Haskell-OpenAPI-Client-Code-Generator
> git checkout nixos-25.11
> git log -1 # Extracts only:
commit bce03f0da42c59c2ea55aad299e53e9a00ee3742 (HEAD -> nixos-25.11, origin/nixos-25.11)
> # Comment out system-ghc: true in stack.yaml, as Stack will fetch the GHC it needs
> # Comment out unnecessary with-hpack: hpack in stack.yaml, as Stack comes with Hpack built-in
> stack test # Extracts only:
...
openapi3-code-generator      > configure (lib + exe + test)
Configuring openapi3-code-generator-0.2.0.0...
openapi3-code-generator      > build (lib + exe + test) with ghc-9.10.3
...
Finished in 0.0252 seconds
48 examples, 0 failures
openapi3-code-generator      > Test suite openapi3-code-generator-test passed

Same positive result with Ubuntu 24.04.3 LTS (via WSL 2).

Same positive result with stack --version:

Version 3.7.1, Git revision cfae313a06ea9f7278e0ac55a58341fa0440f1aa x86_64 hpack-0.38.1

[mpilgrem]

@NorfairKing, this is my best guess of what has happened:

• the nixpkgs project has built a stack executable by reference to the package and Cabal file on Hackage and not by using the Stackage snapshot used by the 'official' build; and
• it has built against the now-deprecated rio-0.1.23.0 package, which has the bug that was fixed in rio-0.1.24.0.

The 'official' version of Stack 3.7.1 is built against rio 0.1.22.0 and is not affected by that bug.

I have now revised the Cabal file for stack-3.7.1 on Hackage to exclude expressly a possible dependency on rio-0.1.23.0, and raised an issue at the nixpkgs repository.