tree 756ee35daa43024a04f36000d348a8450cab4dfc
parent 5e536963311840d1798b4380c4fa71aee5432d48
author Tristan van Berkom <tristan@codethink.co.uk> 1614244135 +0900
committer Tristan van Berkom <tristan@codethink.co.uk> 1614849621 +0900

Make public data immutable

As a part of sealing up the sandbox[0], public data needs to be made
immutable for a number of reasons:

  - Manipulation of public data with python code adds a significant
    risk that public data is not deterministic.

  - Various plugins have been reading public data at initialization time,
    in advance of the build phase where they are allowed to read it off of
    dependencies, this means that currently we have plugins reading invalid
    (pre-mutation) public data from dependencies and thus creating
    unpredictable results.

Summary of changes:

  o element.py:

    - Remove the `__dynamic_public` member, and use only the `__public`
      member for storing public data.

    - Continue to support loading public data from the artifact for the
      purpose of ArtifactElement (ability to observe public data when
      loading the artifacts in `bst artifact` commands).

    - Make `Element.set_public_data()` private/internal (we still need to
      use it elsewhere).

  o filter.py (element plugin):

    - Refactor this plugin to use the new `configure_dependencies()` in order
      to parse the filter element, hold on to the filter element throughout
      the plugin lifetime in order to simplify the plugin.

    - Change how we support the `pass-integration` configuration.

      Public data is now immutable publicly but we still need to automatically
      mutate the filter element's intergration commands at load time.

      Instead of waiting for the build phase like before, now we do it
      immediately at load time.

      This is done early because reverse dependencies are allowed to read
      the public data immediately at load time, so we must provide stable
      public data immediately, before reverse dependencies ever get a chance
      to observe it.

  o tests/elements/filter.py: Removed a test which was asserting the ability
    of plugins to mutate public data, this is no longer allowed and the API
    is now removed.

[0]: https://lists.apache.org/thread.html/r3eb2dce3561cb46ac80c859b14aafb2471aaf3e319a39f70475fe22a%40%3Cdev.buildstream.apache.org%3E