custom_search_query_alter() is too agressive

custom_search_query_alter() is a little too aggressive in it actions. It checks for three things, the node_access tag, the pager tag, and whether a query is being run against search_index.

This works well for core search, but if another module want to use data from search_index, there is no way to get it. For example, I have site where I am excluding a content type with Custom Search, but would like to have a custom search that relies on search_index and search_dataset run on one of the excluded types.