Source maps

bunpy build --sourcemap app.py
# → app.pyz
# → app.pyz.map

The .pyz.map file is a JSON source map that bunpy uses to rewrite tracebacks. When a bundled script raises an exception, bunpy looks up the .pyz.map alongside the .pyz and prints original file names and line numbers instead of bundle-internal offsets.

Source map format

{
  "version": 1,
  "sources": ["app.py", "mylib/utils.py"],
  "mappings": "..."
}

Deploying with source maps

Keep the .pyz.map next to the .pyz on the deployment host. bunpy auto-discovers it by appending .map to the bundle path.

If the map file is absent, tracebacks show bundle-internal line numbers.