Use nil evaluation state if there is no previous evaluation #4197
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The rule engine has a copy of the previous evaluation state as part of its context. Prior to this PR, if there is no previous state for a rule/entity pair, an empty struct would be passed around. This requires each part of the code which uses the previous state (particularly remediations and alerts) to test if the fields in the state struct are the default value. This problem was highlighted in PR #4089 when the types of some the fields changed, requiring the code to be changed to have different default checks.
This PR changes the logic so that a nil pointer is returned if there is no existing state. This makes the check for a lack of previous state to be consistent irrespective of the fields needed or their type.
Summary
Provide a brief overview of the changes and the issue being addressed.
Explain the rationale and any background necessary for understanding the changes.
List dependencies required by this change, if any.
Fixes #(related issue)
Change Type
Mark the type of change your PR introduces:
Testing
Outline how the changes were tested, including steps to reproduce and any relevant configurations.
Attach screenshots if helpful.
Review Checklist: