Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-56571

Remove invariant.h allowlist

    XMLWordPrintableJSON

Details

    • Icon: Improvement Improvement
    • Resolution: Fixed
    • Icon: Major - P3 Major - P3
    • 6.0.0-rc0
    • None
    • None
    • Fully Compatible
    • Service Arch 2022-03-21, Service Arch 2022-04-04
    • 1

    Description

      Propose removing MONGO_ALLOW_INCLUDE_INVARIANT_H (nee MONGO_INCLUDE_INVARIANT_H_WHITELISTED).
      Maybe rename invariant.h to assert_util_detail.h or similar to indicate the relationship better.

      The #ifdef/#error/#endif handshake in invariant.h interferes with indexing that header, as it can't be included by a trivial .cpp file to yield a successful compilation. This is mildly annoying.

      The benefit it is meant to provide is hazy or maybe obsolete. It's meant to force invariant callers to include assert_util.h. But the allowlist requirement is not transitive and cannot be. Most high-level files using invariant.h without assert_util.h do so by including one of the files on the allow list (usually base/string_data.h). So they skirt the requirement, perhaps inadvertently.

      I can't see what the allowlist is trying to protect. I think it's trying to produce a culture where assert_util.h will always be preferred to direct inclusion of invariant.h, which is a good thing. I think maybe renaming invariant.h to assert_util_core.h or assert_util_detail.h and retaining the admonition at the top:

      /**
       * This header is separated from assert_util.h so that the low-level
       * dependencies of assert_util.h (e.g. mongo/base/status_with.h,
       * mongo/base/status.h, mongo/base/string_data.h) can use the invariant macro
       * without causing a circular include chain. It should never be included
       * directly in any other files.
       */
      

      would do this in a more direct way that would not have any technical side effects.

      Attachments

        Activity

          People

            billy.donahue@mongodb.com Billy Donahue
            billy.donahue@mongodb.com Billy Donahue
            Votes:
            0 Vote for this issue
            Watchers:
            3 Start watching this issue

            Dates

              Created:
              Updated:
              Resolved: