Fix CEL validation error when provider field is missing in VolumeSpec

[gabrielm-splunk]

Problem

After upgrading to v3.1.0, customers encountered validation errors when updating existing Standalone CRs that were created with previous versions:

The Standalone "standalone" is invalid: status.smartstore.volumes[0]: 
Invalid value: "object": no such key: provider evaluating rule: 
region is required when provider is aws

This error occurred because the CEL validation rule added in #1740 attempted to access self.provider without first checking if the field exists. In upgrade scenarios, status fields populated by older operator versions may not include the provider field, causing the validation to fail with "no such key: provider".

Root Cause

The original CEL validation rule was:

self.provider != 'aws' || size(self.region) > 0

This rule evaluates self.provider even when the field doesn't exist, violating CEL's requirement to check field existence with has() before accessing optional fields.

Solution

Updated the CEL validation rule in api/v4/common_types.go to:

!has(self.provider) || self.provider != 'aws' || (has(self.region) && size(self.region) > 0)

This change:

1. First checks if provider field exists with !has(self.provider)
2. If it doesn't exist, validation passes (allows backward compatibility)
3. Only validates the AWS region requirement when provider is explicitly set to 'aws'
4. Also checks has(self.region) before accessing the region field

Testing

Reproduced the issue by:

1. Deployed v3.1.0 operator and CRDs to an EKS cluster
2. Created a Standalone CR with the buggy v3.1.0 CRDs
3. Attempted to patch the status with a volume object missing the provider field (simulating an upgrade scenario)
4. Confirmed the error: The Standalone "standalone" is invalid: status.smartstore.volumes[0]: Invalid value: "object": no such key: provider evaluating rule: region is required when provider is aws
5. Applied the fix (regenerated CRDs with the corrected validation rule)
6. Verified the same patch operation succeeds without errors

Impact

• Fixes: Upgrade path from pre-3.1.0 versions where status fields were populated without the provider field
• Maintains: The validation requirement that AWS volumes must have a region
• No impact: On new deployments as they will include the provider field

Checklist

• Changes have been tested and validated
• CRDs regenerated using make manifests
• Commit includes Co-Authored-By for compliance

🤖 Generated with Claude Code