If I change my makefiles do I need to delete the ElectricAccelerator history file?
I know `emake` keeps a history of which jobs collided and needed to be serialized. But if I change the makefiles, will emake detect that the new makefiles are not valid for the build profile that was cached?
You never _have to_ delete the ElectricAccelerator history file in response to changes to your makefiles. Electric Make will automatically evolve the history file as you run subsequent builds, capturing new information, if any, relating to the new things in your build.
However, you may sometimes wish to prune the history file after making substantial architectural changes to the build. For example, if you delete components or targets, or if you change the relative order of targets, then you may effectively invalidate portions of the history file, or you may wind up with stale history data that will over-serialize your build (though it will never cause a build failure!).
The easiest way to prune the history file is to run one full, from-scratch build with the option `--emake-history=create` added to your emake command-line. This will cause emake to regenerate the history file using only the discovered dependencies in that build, rather than merging dependencies discovered in that build with the previously existing history file content as is the default. This will leave you with a history file containing only the currently relevant information from your build.
