[Checkins] [zopefoundation/Products.ZCatalog] 1eb950: Add _not_indexed set to support 'empty' search

[Andreas Gabriel]

  Branch: refs/heads/not-parm-patch
  Home:   https://github.com/zopefoundation/Products.ZCatalog
  Commit: 1eb9502f8040b88bdf143350a3d00e2f01b911b8
      https://github.com/zopefoundation/Products.ZCatalog/commit/1eb9502f8040b88bdf143350a3d00e2f01b911b8
  Author: Andreas Gabriel <gabriel at hrz.uni-marburg.de>
  Date:   2019-04-12 (Fri, 12 Apr 2019)

  Changed paths:
    M src/Products/PluginIndexes/unindex.py

  Log Message:
  -----------
  Add _not_indexed set to support 'empty' search