Commits on Jul 17, 2017

1. Fix merging race conditions …

   Ensure we cache and synchronize appropriately so we don't merge more than
   once or do unsafe reads of the resultset. This has the added benefit of
   reducing the runtime of at_exit hooks by over 66%, since we now do less
   than 1/3 the work.
   
   See https://gist.github.com/jenseng/62465f674f8c02de09ef776f23d4dca4
   for simple repro script.
   
   Basically there are 3 main problems when using merging:
   
   1. `SimpleCov::ResultMerger.stored_data` doesn't synchronize its read,
      so it can see an empty file if another process is writing it.
   2. `SimpleCov::ResultMerger.resultset` calls `.stored_data` twice and
      never caches the result.
   3. `SimpleCov.result` doesn't cache the `@result`, so the default `at_exit`
      behavior causes it to store and merge 3 times. Due to 1. and 2.,
      this is extra bad
   
   This can cause the formatter to miss out on coverage data and/or get the
   wrong values for covered percentages.
   
   Furthermore, if you use OJ, `JSON.parse("") -> nil`, which means
   `.resultset` can be nil, so this race condition causes exceptions as
   seen in simplecov-ruby#406. In addition to fixing the race condition, also add ` || {}`
   to make  `.stored_data` a bit more robust and protect against an empty
   .resultset.json.

   

   jenseng committed Jul 17, 2017
   Configuration menu

   • View commit details
   • Copy full SHA for 6f12dd6
   • Browse repository at this point

   Copy the full SHA

   6f12dd6 View commit details

   Browse the repository at this point in the history