Ability for patches within same resource to overwrite target array or map

[shanproofpoint]

In a composition, if there are 2 patches that contribute information to a target array or map, there should be an option to merge the results but erase what was there first. The inability to take things away from the target array or map results in the need to manually purge the attribute and wait for crossplane to repopulate. This could be nerve wracking in an emergency situation.

        - type: FromCompositeFieldPath
          fromFieldPath: spec.frontDetails.specifiedTlsCerts
          toFieldPath: spec.forProvider.sslCertificates
          policy:
            mergeOptions:
              appendSlice: true
              keepMapValues: true
              mergeOnlyForSisterPatches: true

        - type: FromCompositeFieldPath
          fromFieldPath: status.processingData.discoveredSslCerts
          toFieldPath: spec.forProvider.sslCertificates
          policy:
            mergeOptions:
              appendSlice: true
              keepMapValues: true
              mergeOnlyForSisterPatches: true

given:

  specifiedTlsCerts : [ "a", "b" ]
  discoveredTlsCerts: [ "c", d" ]

  the outcome will be [ "a", "b", "c", "d" ]

and if we later remove "c" the outcome will not change. It then becomes impossible to clean the array or map without manual intervention.

It would be preferable to have an option to have the outcome reflecting the removal of "c" in aggregate: ["a", "b", "d" ]

so some option like :

mergeOnlyForSisterPatches: true

What problem are you facing?

See above.

How could Crossplane help solve your problem?

[chlunde]

what happens with if you do this?

        - type: FromCompositeFieldPath
          fromFieldPath: spec.frontDetails.specifiedTlsCerts
          toFieldPath: spec.forProvider.sslCertificates

        - type: FromCompositeFieldPath
          fromFieldPath: status.processingData.discoveredSslCerts
          toFieldPath: spec.forProvider.sslCertificates
          policy:
            mergeOptions:
              keepMapValues: true

[shanproofpoint]

Thank you @chlunde for your suggestion! I have not tried it, but will. I assume this will successfully cleanup one contributor but leaving the cleanup of the other contributor lacking. But thank you for this partial work around , I will try it soon!

[pedjak]

@shanproofpoint did the workaround help?

[github-actions]

Crossplane does not currently have enough maintainers to address every issue and pull request. This issue has been automatically marked as stale because it has had no activity in the last 90 days. It will be closed in 14 days if no further activity occurs. Leaving a comment starting with /fresh will mark this issue as not stale.

[pedjak]

Fixed via #4896.

[negz]

I'm not sure #4896 fixes this. I think this is a similar situation to the one I described in #4036 (comment). Similar to that issue, I think issue is probably syncing XR -> composed resources rather than claim -> XR. Switching to using function-patch-and-transform should fix the issue.