Deep copy gen generates invalid code if struct has an _ field

[cholman-zd]

Running deepcopy-gen against structs that have _ fields in them generates invalid go code.

Source struct:

type CreateBucketConfiguration struct {
	_ struct{} `type:"structure"`

	LocationConstraint BucketLocationConstraint `type:"string" enum:"true"`
}
type BucketLocationConstraint string

doc.go directives to deepcopy:

// +k8s:deepcopy-gen=package,register

deepcopy directives above structs that the above struct is a child of (not sure if this makes a difference or not - this is autogenerated code from the operator sdk)

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

Output by deepcopy-gen:

// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
func (in *CreateBucketConfiguration) DeepCopyInto(out *CreateBucketConfiguration) {
	*out = *in
	out._ = in._
	return
}

Setting or accessing _ fields is invalid.

I applied the following patch locally and it outputs correct code (ie does not attempt to copy the _ field). No idea if this is the correct way to solve the problem though.

diff --git a/vendor/k8s.io/gengo/examples/deepcopy-gen/generators/deepcopy.go b/vendor/k8s.io/gengo/examples/deepcopy-gen/generators/deepcopy.go
index 4548108..1d90578 100644
--- a/vendor/k8s.io/gengo/examples/deepcopy-gen/generators/deepcopy.go
+++ b/vendor/k8s.io/gengo/examples/deepcopy-gen/generators/deepcopy.go
@@ -823,6 +823,9 @@ func (g *genDeepCopy) doStruct(t *types.Type, sw *generator.SnippetWriter) {

 	// Now fix-up fields as needed.
 	for _, m := range ut.Members {
+		if m.Name == "_" {
+			continue
+		}
 		ft := m.Type
 		uft := underlyingType(ft)

After applying this patch, output is as expected:

// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
func (in *CreateBucketConfiguration) DeepCopyInto(out *CreateBucketConfiguration) {
	*out = *in
	return
}

[fejta-bot]

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[cholman-zd]

/remove-lifecycle stale

[cholman-zd]

There is an open PR #134 to fix this and it would be great if someone could help get that merged and applied.

[lavalamp]

That PR is waiting on a test. I clarified where one could be added.

…

On Sun, Apr 21, 2019 at 1:51 PM Chris Holman ***@***.***> wrote: There is an open PR #134 <#134> to fix this and it would be great if someone could help get that merged and applied. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#133 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAE6BFRTEORKI4YL4SQQ6RLPRTHUBANCNFSM4GQ3Z7GQ> .

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[k8s-ci-robot]

@fejta-bot: Closing this issue.

In response to this:

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[lavalamp]

/reopen /lifecycle frozen

…

On Thu, Sep 19, 2019 at 10:55 AM Kubernetes Prow Robot < ***@***.***> wrote: @fejta-bot <https://github.com/fejta-bot>: Closing this issue. In response to this <#133 (comment)>: Rotten issues close after 30d of inactivity. Reopen the issue with /reopen. Mark the issue as fresh with /remove-lifecycle rotten. Send feedback to sig-testing, kubernetes/test-infra and/or fejta <https://github.com/fejta>. /close Instructions for interacting with me using PR comments are available here <https://git.k8s.io/community/contributors/guide/pull-requests.md>. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra <https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:> repository. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#133?email_source=notifications&email_token=AAE6BFSTS44OCXJ56C34I3LQKO4JHA5CNFSM4GQ3Z7G2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD7EJYKY#issuecomment-533240875>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAE6BFWX3W3QOQ3G7E4ZLILQKO4JHANCNFSM4GQ3Z7GQ> .

[k8s-ci-robot]

@lavalamp: Reopened this issue.

In response to this:

/reopen
/lifecycle frozen

On Thu, Sep 19, 2019 at 10:55 AM Kubernetes Prow Robot <
[email protected]> wrote:

@fejta-bot https://github.com/fejta-bot: Closing this issue.

In response to this
#133 (comment):

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta
https://github.com/fejta.
/close

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[grim-fendango]

/reopen
/lifecycle frozen

[thockin]

gengo/v2 (#259) moves deepcopy-gen to k8s.io/code-generator.

[thockin]

kubernetes/kubernetes#123838