operator-sdk generate crds command fails with panic: runtime error: invalid memory address or nil pointer dereference

[shevchyk-aa]

Bug Report

What did you do?
operator-sdk new test-op
cd test-op/
operator-sdk add api --api-version=some.org/v1 --kind=SomeApp
operator-sdk add controller --api-version=some.org/v1 --kind=SomeApp

vi pkg/apis/some/v1/someapp_types.go

Replace definition of SomeAppSpec with following
type SomeAppSpec struct {
Parent struct {
Child string `json:"child"`
} `json:"parent"`
}

operator-sdk generate crds

What did you expect to see?
Updated CRD with struct like:
parent:
child: "some_value"

What did you see instead? Under which circumstances?
Panic with stack trace:

$ operator-sdk generate crds
INFO[0000] Running CRD generator.
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x18e8f5c]

goroutine 1 [running]:
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0xc000bdef00, 0xc0008b2620, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:322 +0x9c
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0xc000bdef00, 0x2642ee0, 0xc0008b2620, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:164 +0x3a6
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0xc0013278b0, 0xc0008b2660, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:375 +0x491
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0xc0013278b0, 0x2642ee0, 0xc0008b2660, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:164 +0x3a6
sigs.k8s.io/controller-tools/pkg/crd.infoToSchema(...)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:107
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedSchemaFor(0xc00024a0a0, 0xc0008b2200, 0xc00089c080, 0xb)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/parser.go:174 +0x321
sigs.k8s.io/controller-tools/pkg/crd.(*schemaContext).requestSchema(0xc000bdeae0, 0x0, 0x0, 0xc00089c080, 0xb)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:99 +0x9e
sigs.k8s.io/controller-tools/pkg/crd.localNamedToSchema(0xc000bdeae0, 0xc0008b29e0, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:220 +0x1b1
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0xc000bdeae0, 0x2642aa0, 0xc0008b29e0, 0x1f)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:154 +0x2e9
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0xc0013282a8, 0xc0008b2aa0, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:375 +0x491
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0xc0013282a8, 0x2642ee0, 0xc0008b2aa0, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:164 +0x3a6
sigs.k8s.io/controller-tools/pkg/crd.infoToSchema(...)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/schema.go:107
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedSchemaFor(0xc00024a0a0, 0xc0008b2200, 0xc00089c120, 0x7)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/parser.go:174 +0x321
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedFlattenedSchemaFor(0xc00024a0a0, 0xc0008b2200, 0xc00089c120, 0x7)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/parser.go:186 +0xd8
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedCRDFor(0xc00024a0a0, 0xc00054e3ae, 0x8, 0xc00089c120, 0x7, 0x0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/spec.go:85 +0x615
sigs.k8s.io/controller-tools/pkg/crd.Generator.Generate(0x0, 0x0, 0x0, 0xc000376a80, 0x1, 0x1, 0xc00024a050, 0x2603d00, 0x2605ae0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/crd/gen.go:108 +0x356
sigs.k8s.io/controller-tools/pkg/genall.(*Runtime).Run(0xc000410680, 0xc00064fce0)
pkg/mod/sigs.k8s.io/[email protected]/pkg/genall/genall.go:171 +0x15e
github.com/operator-framework/operator-sdk/internal/generate/gen.(*cachedRunner).Run(0xc00064fda0, 0xc00064fce0, 0x3, 0x3, 0x383e160, 0xc00054f220)
src/github.com/operator-framework/operator-sdk/internal/generate/gen/generator.go:150 +0x86
github.com/operator-framework/operator-sdk/internal/generate/crd.Generator.generateGo(0x0, 0x0, 0x224d339, 0xb, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
src/github.com/operator-framework/operator-sdk/internal/generate/crd/crd.go:149 +0x53f
github.com/operator-framework/operator-sdk/internal/generate/crd.Generator.Generate(0x0, 0x0, 0x224d339, 0xb, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
src/github.com/operator-framework/operator-sdk/internal/generate/crd/crd.go:111 +0x1b5
github.com/operator-framework/operator-sdk/cmd/operator-sdk/internal/genutil.CRDGen(0x22361f3, 0x2, 0x2238100, 0x4)
src/github.com/operator-framework/operator-sdk/cmd/operator-sdk/internal/genutil/crds.go:38 +0x11e
github.com/operator-framework/operator-sdk/cmd/operator-sdk/generate.crdsFunc(0xc000617b80, 0x383c3a8, 0x0, 0x0, 0x0, 0x0)
src/github.com/operator-framework/operator-sdk/cmd/operator-sdk/generate/crds.go:60 +0x4b
github.com/spf13/cobra.(*Command).execute(0xc000617b80, 0x383c3a8, 0x0, 0x0, 0xc000617b80, 0x383c3a8)
pkg/mod/github.com/spf13/[email protected]/command.go:842 +0x460
github.com/spf13/cobra.(*Command).ExecuteC(0xc000608000, 0x2603f60, 0xc0004df700, 0x0)
pkg/mod/github.com/spf13/[email protected]/command.go:950 +0x349
github.com/spf13/cobra.(*Command).Execute(...)
pkg/mod/github.com/spf13/[email protected]/command.go:887
github.com/operator-framework/operator-sdk/cmd/operator-sdk/cli.RunLegacy(0xc0000a4000, 0x0)
src/github.com/operator-framework/operator-sdk/cmd/operator-sdk/cli/legacy.go:49 +0x11b
main.main()
src/github.com/operator-framework/operator-sdk/cmd/operator-sdk/main.go:43 +0x92

Environment

• operator-sdk version:

$ operator-sdk version
operator-sdk version: "v0.18.2", commit: "f059b5e17447b0bbcef50846859519340c17ffad", kubernetes version: "v1.18.2", go version: "go1.13.10 linux/amd64"

• go version:

"go1.13.10 linux/amd64"

• Kubernetes version information:

kubernetes version: "v1.18.2"

• Kubernetes cluster kind:

Local, created with kubeadm

• Are you writing your operator in ansible, helm, or go?
  Go

[joelanford]

@shevchyk-aa That appears to be an issue with how controller-tools handles the anonymous parent struct.

As a workaround, you can get the desired behavior by declaring parent as a separate struct:

type SomeAppSpec struct {
    Parent Parent `json:"parent"`
}

type Parent struct {
    Child string `json:"child"`
}

[joelanford]

It appears anonymous structs are specifically not allowed, and the logic currently panics.

This PR (still open) will help clarify the issue by ensuring a proper error message is returned in this situation: kubernetes-sigs/controller-tools#415