no warning when project gem has un-added files

[mattgillooly]

When using the pipeline-as-a-gem deployment strategy, the project's gem is built using git-ls. If you have added files to the project, but not yet added them to the git repo, then the deployed gem will be lacking these files. This can be very confusing to diagnose, as all local tests on your development machines will find the file.

Bundler's gem deployment Rake tasks get around this by refusing to release a gem if there are uncommitted changes in the working directory.[1] We should consider whether a similar strategy would be worth adding to pipely, to prevent this confusing type of failure.

Alternatively, the overhead of committing changes before each pipeline deployment may introduce too much friction, and we might consider whether we can avoid the use of git-ls when building the gem.

[1] https://github.com/bundler/bundler/blob/6725c27bdd31c60f5d768360debc508912529f97/lib/bundler/gem_helper.rb#L119-L129

[mattgillooly]

@mguymon - Thanks for clarifying this earlier. Let's track the impact of this issue here until we have a resolution.