Incompatible API behavior during Grunt 0.4 to 1.x migration

Confirmed API Breaks

Grunt 1.x no longer exposes Lodash via grunt.util._. Any call to grunt.util._.each, .map, .merge etc throws. Also several helpers in grunt.file and grunt.util were removed or changed signatures, affecting grunt.file.expand, grunt.file.copy, and grunt.util.spawn.

Likely Adjustments

Grunt 1.x enforces the strict wrapper module.exports = function(grunt){ ... } and expects explicit paths for grunt.loadTasks. Direct access to grunt.config.data is discouraged; use grunt.config.get/set. Additionally, the return shape of grunt.file.expandMapping changed, so legacy rename callbacks need updating.

Migration Steps

1. Check versions: run grunt --version and node --version to ensure Node ≥4 and Grunt 1.x.
2. Replace all grunt.util._ calls with require('lodash') or native Array/Object methods.
3. Audit grunt.file usage: rewrite expand, copy, and spawn calls to match 1.x signatures.
4. Update expandMapping calls: adjust mapping options and rename functions to match the new src/dest object shape.
5. Wrap the Gruntfile in the strict module.exports = function(grunt){ ... } form and make grunt.loadTasks paths absolute or relative to the Gruntfile directory.
6. Run the build to verify tasks execute.

One Diagnostic Detail Needed

Which exact Grunt 1.x version are you targeting (e.g., 1.0.4, 1.5.3)? Option parsing and config merging behavior varied between 1.0–1.5, so the precise version may change the recommended workaround for a few edge cases.