Quantity type's validation does not conform to its serialization specification

What happened?

We found that the the serialization specification for the Quantity type does not conform to the real implementation of parse function. The serialization specification is found here in the documentation https://github.com/kubernetes/kubernetes/blob/f02682c628c530219966a00ae002d799f0d813dc/staging/src/k8s.io/apimachinery/pkg/api/resource/quantity.go#L31-L66.

In the specification, Quantity allows the suffix to contain a decimalExponent, but the validation seems to only allow integers as shown here.

Concretely, when specifying .07893E985.90504 as the value for a Quantity field, the parseQuantityString function rejects it and outputs the ErrFormatWrong message.

Additionally, @Porges noted that n and u are permitted as suffix in the parseQuantityString function but not in the specification.

What did you expect to happen?

We expected that the implementation of the validation conform to the serialization specification for the Quantity type.

How can we reproduce it (as minimally and precisely as possible)?

Specify a Quantity type field as .07893E985.90504, and observe the error message from reflector.go:

E0421 07:19:52.910713       1 reflector.go:138] pkg/mod/k8s.io/client-go@v0.21.3/tools/cache/reflector.go:167: Failed to watch *v1beta1.RabbitmqCluster: failed to list *v1beta1.RabbitmqCluster: v1beta1.RabbitmqClusterList.Items: []v1beta1.RabbitmqCluster: v1beta1.RabbitmqCluster.Spec: v1beta1.RabbitmqClusterSpec.Rabbitmq: v1beta1.RabbitmqClusterConfigurationSpec.Persistence: v1beta1.RabbitmqClusterPersistenceSpec.Storage: unmarshalerDecoder: quantities must match the regular expression '^([+-]?[0-9.]+)([eEinumkKMGTP]*[-+]?[0-9]*)$', error found in #10 byte of ...|985.90504"},"rabbitm|..., bigger context ...|de":{},"persistence":{"storage":".07893E985.90504"},"rabbitmq":{"additionalConfig":"cluster_partitio|...

Anything else we need to know?

No response

Kubernetes version

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.1", GitCommit:"5e58841cce77d4bc13713ad2b91fa0d961e69192", GitTreeState:"clean", BuildDate:"2021-05-12T14:11:29Z", GoVersion:"go1.16.3", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.0", GitCommit:"cb303e613a121a29364f75cc67d3d580833a7479", GitTreeState:"clean", BuildDate:"2021-04-08T16:25:06Z", GoVersion:"go1.16.1", Compiler:"gc", Platform:"linux/amd64"}

Cloud provider

OS version

# On Linux:
$ cat /etc/os-release
NAME="Ubuntu"
VERSION="20.04.3 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.3 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal
$ uname -a
Linux riverrun 5.13.0-39-generic #44~20.04.1-Ubuntu SMP Thu Mar 24 16:43:35 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

# On Windows:
C:\> wmic os get Caption, Version, BuildNumber, OSArchitecture
# paste output here

Install tools

Container runtime (CRI) and version (if applicable)

Related plugins (CNI, CSI, ...) and versions (if applicable)