string([]byte{'a'})      // not a constant: []byte{'a'} is not a constant
(*int)(nil)              // not a constant: nil is not a constant, *int is not a boolean, numeric, or string type
int(1.2)                 // illegal: 1.2 cannot be represented as an int
string(65.0)             // illegal: 65.0 is not an integer constant
</pre>

<p>

pkg go/build/constraint, type AndExpr struct, Y Expr
pkg go/build/constraint, type Expr interface, Eval(func(string) bool) bool
pkg go/build/constraint, type Expr interface, String() string
pkg go/build/constraint, type Expr interface, unexported methods
pkg go/build/constraint, type NotExpr struct
pkg go/build/constraint, type NotExpr struct, X Expr
pkg go/build/constraint, type OrExpr struct

  // WhenUnsatisfiable indicates how to deal with a pod if it doesn't satisfy
  // the spread constraint.
  // - DoNotSchedule (default) tells the scheduler not to schedule it.
  // - ScheduleAnyway tells the scheduler to schedule the pod in any location,
  //   but giving higher precedence to topologies that would help reduce the
  //   skew.
  // A constraint is considered "Unsatisfiable" for an incoming pod

- Added `optionalOldSelf` to `x-kubernetes-validations` to support ratcheting CRD schema constraints. ([#121034](https://github.com/kubernetes/kubernetes/pull/121034), [@alexzielenski](https://github.com/alexzielenski))

- Pod spread constraints have been added in alpha. You can use these constraints to control how Pods are spread across the cluster among failure-domains. ([#77327](https://github.com/kubernetes/kubernetes/pull/77327), [#77760](https://github.com/kubernetes/kubernetes/pull/77760), [#77828](https:/...

- Revised the logic for DaemonSet rolling update to exclude nodes if scheduling constraints are not met.

- New parameter `defaultingType` for `PodTopologySpread` plugin allows to use k8s defined or user provided default constraints ([#95048](https://github.com/kubernetes/kubernetes/pull/95048), [@alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]

### Storage Capacity Tracking

  matching the spreading selector on those excluded nodes (not matching the node affinity/selector),
  especially when the `topologyKey` is not node-level. Revisit the node affinity and/or pod selector in the
  topology spread constraints to avoid this scenario. ([#107009](https://github.com/kubernetes/kubernetes/pull/107009), [@kerthcet](https://github.com/kerthcet))

- Graduated support for `minDomains` in pod topology spread constraints, to general availability.
  The `MinDomainsInPodTopologySpread` feature gate no longer has any effect, and the field is