feat: add haskell-language-server 2.14.0.0

[0chroma]

Summary

Add the Haskell Language Server (HLS) v2.14.0.0 to the package registry, enabling Haskell LSP support for editors like Neovim, VS Code, and Emacs.

Context

HLS is the official Language Server Protocol implementation for Haskell, providing features like go-to-definition, type hover, code actions, and refactoring. It was missing from the registry, blocking Haskell development workflows.

Changes

• Added packages/haskell-language-server/build.ncl — Build spec sourcing from GitHub tag 2.14.0.0 with automatic extraction
• Added packages/haskell-language-server/build.sh — Build script using GHC + Cabal with dynamic linking

Key Implementation Details

• Builds from source using cabal build exe:haskell-language-server (not prebuilt binaries per guidelines)
• Uses ldd to discover and copy all required shared Haskell libraries at runtime, avoiding static linking issues (Haskell libs aren't PIC-compatible)
• Network access enabled via needs = { dns = {}, internet = {} } for Cabal dependency index updates
• All 14 min check checks pass, including standalone version test

Use Cases

• Haskell development with LSP-enabled editors
• Type checking and refactoring for Haskell projects
• Integration with cabal and Stack projects

Testing

# Validate the package spec
min check --packages haskell-language-server

# Build the package
min patched-build haskell-language-server

# Verify the binary works
min add haskell-language-server
haskell-language-server --version

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[edge-delta]

⚠️ Packaging and Operational Risk: Unsafe Dynamic Library Bundling

Hi @0chroma! Thanks for adding haskell-language-server.

During a review of the aggregated unstable build, we identified a significant operational and runtime risk in packages/haskell-language-server/build.sh:

The current script uses ldd to copy all linked dynamic libraries into $OUTPUT_DIR/usr/lib:

# Copy all shared Haskell libraries the binary depends on
for lib in $(ldd "$HLS_BIN" | grep '\.so' | awk '{print $3}'); do
  if [ -n "$lib" ] && [ -f "$lib" ]; then
    cp "$lib" "$OUTPUT_DIR"/usr/lib/
  fi
done

Why this is a problem:

1. System Library Pollution: ldd returns system-wide libraries such as libc.so.6, libm.so.6, libpthread.so.0, and the dynamic linker. Copying these into /usr/lib/ of the package packages them along with haskell-language-server.
2. Dynamic Loader Collisions & Crashes: Distributing duplicate, potentially out-of-sync or incompatible core system GLIBC libraries in application packages is highly risky. It can cause severe runtime crashes (segmentation faults), loader conflicts, or even break the base system container's loader when installed.
3. Bloat: It dramatically inflates the package size unnecessarily.

Recommended Fix:

Haskell executable targets built by Cabal statically link Haskell package dependencies by default. Standard external C library dependencies (such as GLIBC) should be resolved dynamically from the base system (since glibc is already in your runtime_deps).

Therefore, you can safely remove the library-copying block entirely. Here is the recommended clean build script:

#!/bin/bash
set -euo pipefail

# The source tarball is already extracted with strip_prefix, so we're in the source root

# Build HLS for the GHC version available in the sandbox
export GHC="$(command -v ghc)"
export CABAL="$(command -v cabal)"

# Update cabal package index
cabal update

# Build HLS with the available GHC version
cabal build \
  --ghc-options="-j$(nproc)" \
  exe:haskell-language-server

# Install to OUTPUT_DIR
mkdir -p "$OUTPUT_DIR"/usr/bin

# Find and copy the built binary from cabal's build directory
HLS_BIN=$(cabal list-bin exe:haskell-language-server)
cp "$HLS_BIN" "$OUTPUT_DIR"/usr/bin/

And in packages/haskell-language-server/build.ncl, you can simplify the outputs definition by removing the libs entry:

  outputs = {
    hls = { glob = "usr/bin/haskell-language-server" } | OutputBin,
  },

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