🐛 Ensure holder field path in GeneratePatchRequest is set based on contract

[sbueringer]

Signed-off-by: Stefan Büringer [email protected]

What this PR does / why we need it:

Since CAPI v1.11.0 the patch engine always sets the holder field path in a GeneratePatchesRequest for the CP InfraMachineTemplate to spec.machineTemplate.spec.infrastructureRef.
This broke existing Runtime Extension implementations that were checking for spec.machineTemplate.infrastructureRef (the v1beta1 path).

With this PR we are now setting the holder field path depending on which contract the corresponding control plane object implements.

Examples:

• KCP v1beta1 implements the v1beta1 contract so fieldPath will be set to spec.machineTemplate.infrastructureRef
• KCP v1beta2 implements the v1beta2 contract so fieldPath will be set to spec.machineTemplate.spec.infrastructureRef

This way existing implementations for v1beta1 that matched on the old path still work and new implementations can either match for both paths or for the absolutely correct one based on contract. Both would be fine.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

[sbueringer]

/cherry-pick release-1.11

[k8s-infra-cherrypick-robot]

@sbueringer: once the present PR merges, I will cherry-pick it on top of release-1.11 in a new PR and assign it to you.

In response to this:

/cherry-pick release-1.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[sbueringer]

/test pull-cluster-api-e2e-main

[sbueringer]

/assign @fabriziopandini

[sbueringer]

/test pull-cluster-api-e2e-main

[randomvariable]

/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 1f1caba2bea57433bec6eaa61f0996393b6825e2

[fabriziopandini]

Nice patch.
I double checked all the usage of HolderReference.FieldPath, HolderReference and did not found other places where we need similar changes.
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fabriziopandini

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[k8s-infra-cherrypick-robot]

@sbueringer: #12684 failed to apply on top of branch "release-1.11":

Applying: Ensure holder field path in GeneratePatchRequest is set based on contract
Using index info to reconstruct a base tree...
M	exp/topology/desiredstate/desired_state.go
Falling back to patching base and 3-way merge...
Auto-merging exp/topology/desiredstate/desired_state.go
CONFLICT (content): Merge conflict in exp/topology/desiredstate/desired_state.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 Ensure holder field path in GeneratePatchRequest is set based on contract

In response to this:

/cherry-pick release-1.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.