Registry Migration

When you rename home/ to users/, the registry structure updates immediately since it derives from the directory tree. But every registry.home.alice reference now points to a nonexistent path. The imp.refactor tool detects these broken references and rewrites them.

Installation

Add imp.refactor to your flake inputs:

{
  inputs.imp-refactor.url = "github:imp-nix/imp.refactor";
}

Or run directly:

nix run github:imp-nix/imp.refactor -- detect
nix run github:imp-nix/imp.refactor -- apply --write

Usage

From your flake directory:

# Detect broken refs and show suggestions
imp-refactor detect

# Preview changes (dry-run)
imp-refactor apply

# Apply fixes to files
imp-refactor apply --write

# Interactive mode: confirm each file
imp-refactor apply --interactive

Comparing against previous commits

When comparing working tree files against a previous registry state (before a rename):

# Compare against previous commit
imp-refactor detect --git-ref HEAD^

# Compare against a branch
imp-refactor detect --git-ref main

# Apply fixes based on old registry
imp-refactor apply --git-ref HEAD^ --write

How it works

The tool scans .nix files for registry.X.Y.Z patterns using AST parsing (not regex), then checks each against the evaluated registry. Paths that fail lookup are broken references.

For each broken reference, it attempts to find a replacement by matching the leaf name. If home.alice is broken and users.alice exists, it suggests the mapping. This heuristic works because renames typically preserve the final component.

Explicit rename mappings

When the leaf-name heuristic fails (ambiguous matches or leaf name changes), supply explicit mappings:

imp-refactor apply --rename home=users --rename svc.db=services.database --write

The longest matching prefix wins, so --rename home.alice=admins.alice takes precedence over --rename home=users for paths starting with home.alice.

Ambiguous renames

When a leaf name exists in multiple locations, the tool cannot determine which is correct. If you renamed home/ to users/ and also created legacy/alice, the reference home.alice could map to either. These appear with an "ambiguous" reason; use --rename to resolve them explicitly.