Package Validation

All package changes must pass three validation steps:

1. Evaluation Check

Verify Nix expression evaluates correctly:

nix-instantiate -A <package-name>

Expected: /nix/store/abc123...-package-1.0.0.drv

For non-derivations:

nix-instantiate --eval -A <attribute>

2. Build Check

Verify package builds successfully:

nix-build -A <package-name>

Expected: result symlink to /nix/store/xyz789...-package-1.0.0

Inspect results:

ls -la result/
./result/bin/example --version
ldd result/lib/libexample.so

3. Format Check

Ensure code follows formatting standards:

nix fmt <path-to-file>

Format all modified files:

git diff --name-only '*.nix' | xargs -I {} nix fmt {}

Checking Dependencies

Verify dependencies exist before porting:

# Single dependency
nix-instantiate -A zlib

# Multiple dependencies
for dep in acl lzo cmocka zlib zstd; do
  echo -n "$dep: "
  nix-instantiate -A $dep >/dev/null 2>&1 && echo "✓" || echo "✗"
done

DO NOT search top-level.nix with grep. Packages in pkgs/ and pkgs-many/ are auto-registered.

Common Errors

Evaluation Errors

Missing dependency:

error: attribute 'somelib' missing

Port the dependency or add TODO comment.

Syntax error:

error: syntax error, unexpected ')'

Fix the syntax in the Nix expression.

Build Errors

Missing build tool:

error: Program 'pkg-config' not found

Add to nativeBuildInputs.

Missing library:

/nix/store/.../bin/ld: cannot find -lz

Add to buildInputs.

Test failures: Tests are disabled by default. Investigate or keep disabled.

Complete Validation Workflow

# Validate a package
PACKAGE="example"

# 1. Evaluate
nix-instantiate -A $PACKAGE

# 2. Build
nix-build -A $PACKAGE

# 3. Test result
./result/bin/$PACKAGE --version

# 4. Format
nix fmt pkgs/$PACKAGE/default.nix

Validation Checklist

• nix-instantiate -A <package> succeeds
• nix-build -A <package> succeeds
• Built binary/library works
• All dependencies verified with nix-instantiate
• nix fmt run on all edited files
• No meta.maintainers or meta.teams
• TODO comments for missing dependencies

Advanced Validation

Check closure size:

nix-store -q --tree $(nix-build -A example --no-out-link)

Check runtime dependencies:

nix-store -q --references $(nix-build -A example --no-out-link)

Rebuild from scratch:

nix-build -A example --rebuild

Reproducibility check:

nix-build -A example --check