fix: allow rollout and percentage zero values in YAML serialization

[markphelps]

Summary

Fixes validation errors when using rollout value of 0 in variant flag distributions and percentage value of 0 in boolean flag threshold rollouts.

Problem

When updating a variant flag with a distribution rollout value of 0, the operation fails with a CUE validation error: incomplete value >=0 & <=100. This occurs because the omitempty tag on the Rollout field in Distribution and Percentage field in ThresholdRule causes zero values to be omitted during YAML serialization, leading to validation failure.

Changes

• Modified internal/ext/common.go: Removed omitempty tags from:
  • Distribution.Rollout field
  • ThresholdRule.Percentage field
• Added internal/ext/common_test.go: Comprehensive tests for YAML and JSON serialization with zero values
• Added core/validation/testdata/valid_zero_values.yaml: Test data with rollout: 0 and percentage: 0
• Modified core/validation/validate_test.go: Added test case for zero values validation

Testing

• All existing tests pass
• New tests verify zero values serialize correctly in both YAML and JSON
• CUE validation now passes for rollout: 0 and percentage: 0
• Linting and formatting checks pass

Backward Compatibility

This change is backward compatible since:

• Existing YAML files with rollout/percentage values continue to work
• The only change is that zero values are now explicitly serialized instead of omitted
• CUE validation is more consistent

Fixes #4677

[dosubot]

Related Documentation

Checked 2 published document(s). No updates required.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.52%. Comparing base (1841e10) to head (27788c7).
⚠️ Report is 1 commits behind head on v2.

Additional details and impacted files

@@           Coverage Diff           @@
##               v2    #4678   +/-   ##
=======================================
  Coverage   62.52%   62.52%           
=======================================
  Files         131      131           
  Lines       15510    15510           
=======================================
  Hits         9698     9698           
  Misses       5139     5139           
  Partials      673      673           

Flag	Coverage Δ
integrationtests	36.91% <ø> (ø)
unittests	52.63% <ø> (-0.02%)	⬇️

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[Copilot]

Pull Request Overview

This PR fixes validation errors when using zero values (0 or 0.0) for rollout percentages in variant flag distributions and threshold rollouts in boolean flags by removing the omitempty YAML/JSON tags that were causing these fields to be omitted during serialization.

• Removes omitempty tags from Distribution.Rollout and ThresholdRule.Percentage fields in struct definitions
• Adds comprehensive test coverage for YAML and JSON serialization with zero values
• Adds validation test data and test case to ensure CUE validation works with zero values

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
internal/ext/common.go	Removes omitempty tags from Rollout and Percentage fields to ensure zero values are serialized
internal/ext/common_test.go	Adds comprehensive tests for YAML and JSON serialization with zero rollout and percentage values
core/validation/validate_test.go	Adds test case to verify validation passes with zero values
core/validation/testdata/valid_zero_values.yaml	Test data containing rollout: 0 and percentage: 0 configurations

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[dosubot]

Documentation updates

Checked 2 published document(s). No updates required.

^{How did I do? Any feedback?}