[jira] [Created] (FLINK-39509) Mutating webhook produce spurious object modifications on no-op patches

["Dennis-Mircea Ciupitu (Jira)" <ji...@apache.org>]

Dennis-Mircea Ciupitu created FLINK-39509:
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             Summary: Mutating webhook produce spurious object modifications on no-op patches
                 Key: FLINK-39509
                 URL: https://issues.apache.org/jira/browse/FLINK-39509
             Project: Flink
          Issue Type: Bug
          Components: Kubernetes Operator
            Reporter: Dennis-Mircea Ciupitu


The mutating webhook's {{FlinkMutator}} always performs a Jackson {{convertValue}} serialization round-trip (HasMetadata -> typed class -> back) on every CREATE/UPDATE admission request. When no {{FlinkResourceMutator}} actually modifies the resource, the round-tripped object can serialize differently from the original input (e.g., field ordering, null handling), causing the webhook to return a JSON patch to the API server even though nothing was logically changed.

This leads to inconsistent behavior where {{kubectl patch}} reports {{patched}} instead of {{patched (no change)}} for resources like {{FlinkDeployment}}, even when the patch contains no effective change (e.g., setting {{restartNonce}} to its current value). While this does not trigger an actual reconciliation (the operator correctly detects no spec diff), it is confusing and causes unnecessary {{resourceVersion}} bumps on the Kubernetes object.



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