lib.fileset.trace

Incrementally evaluate and trace a file set in a pretty way. This function is only intended for debugging purposes. The exact tracing format is unspecified and may change.

This function takes a final argument to return. In comparison, traceVal returns the given file set argument.

This variant is useful for tracing file sets in the Nix repl.

Inputs

fileset

The file set to trace.

This argument can also be a path, which gets implicitly coerced to a file set.

val

The value to return.

Type

trace :: FileSet -> Any -> Any

Examples

trace (unions [ ./Makefile ./src ./tests/run.sh ]) null
=>
trace: /home/user/src/myProject
trace: - Makefile (regular)
trace: - src (all files in directory)
trace: - tests
trace:   - run.sh (regular)
null

Noogle detected

trace =
    fileset:
    let
      # "fileset" would be a better name, but that would clash with the argument name,
      # and we cannot change that because of https://github.com/nix-community/nixdoc/issues/76
      actualFileset = _coerce "lib.fileset.trace: Argument" fileset;
    in
    seq (_printFileset actualFileset) (x: x);