• Fix broken test TestDefaultPodGangSet in operator/internal/webhook/admission/pgs/defaulting/podgangset_test.go.
• Remove scheduler-api/hack/tools.go, and use the tool section in scheduler-api/go.mod, following the Go 1.24 convention, making it uniform across all directories in the repository.
• Migrate to golangci-lint@v2.1.1 (major version upgrade).
• Fix numerous lint errors raised by golangci-lint.
  • Comments on exported tokens.
  • Renaming unused variables to _. These unused variables can be renamed to appropriate names when necessary, as most are trivial. Added suggestions in places where deemed necessary.
• make targets are made holistic by replicating wherever necessary.
• make generate wherever applicable.
• Upgrade to goimports-reviser@3.9.1 since older versions are not supported by Go 1.24.
• Upgrade to kind@v0.27.0.
• Revise imports in all files.

NOTE: make generate in scheduler-api fails, which has an easy enough fix, but affects the API so I refrained from making the change there. Input appreciated @unmarshall @sanjaychatterjee.
The type NamespacedName does not include JSON tags; therefore the field PodReferences in the struct:

// PodGroup defines a set of pods in a PodGang that share the same PodTemplateSpec.
type PodGroup struct {
	// PodReferences is a list of references to the Pods that are part of this group.
	PodReferences []types.NamespacedName `json:"podReferences"`
	// MinReplicas is the number of replicas that needs to be gang scheduled.
	// If the MinReplicas is greater than len(PodReferences) then scheduler makes the best effort to schedule as many pods beyond
	// MinReplicas. However, guaranteed gang scheduling is only provided for MinReplicas.
	MinReplicas int32 `json:"minReplicas"`
}

will cause issues while generating code. controller-gen expects each struct's fields to have JSON tags, and this imported type from k8s.io/apimachinery/pkg/types does not.

• A potential solution is to define:

  type OwnNamespacedName struct {
      Namespace string `json:"namespace"`
      Name      string `json:"name"`
  }

  in the same package, and then change PodGroup to:

  // PodGroup defines a set of pods in a PodGang that share the same PodTemplateSpec.
  type PodGroup struct {
      PodReferences []OwnNamespacedName `json:"podReferences"`
      MinReplicas int32 `json:"minReplicas"`
  }

  I've done the following locally and have verified that make generate succeeds.

This project has done the same.

Given the size of the PR, I've structured it such that it will be trivial to review commit wise.
I would highly recommend doing so since quite a few commits can be skipped as they are generated.

PLEASE SQUASH AND MERGE, DO NOT CREATE A MERGE COMMIT OR REBASE AND MERGE as there are multiple commits, to avoid polluting the git history in main.