panic on type casting `*types.Named` using Go 1.23 because of new `*types.Alias`

[mtardy]

Using it with Go 1.22 works and break with Go 1.23, I think it's related to this:

In the latest version of go, a change was made to the generation of Alias types. From the release notes:

By default, go/types now produces Alias type nodes for type aliases. This behavior can be controlled by the GODEBUG gotypesalias flag. Its default has changed from 0 in Go 1.22 to 1 in Go 1.23.

When using Go 1.23 and tools/controller-gen to generates my CRDs I get the following panic:

panic: interface conversion: types.Type is *types.Alias, not *types.Named

goroutine 1 [running]:
sigs.k8s.io/controller-tools/pkg/crd.localNamedToSchema(0x400186f028, 0x400098b340)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:269 +0x4ac
sigs.k8s.io/controller-tools/pkg/crd.mapToSchema(0x4001b0d6b0, 0x400097b410)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:346 +0x36c
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x4001b0d6b0, {0xa38628, 0x400097b410})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:203 +0x74
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0x400186f518, 0x4000975c50)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:455 +0xa3c
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x400186f518, {0xa38538, 0x4000975c50})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:207 +0x90
sigs.k8s.io/controller-tools/pkg/crd.infoToSchema(0x400186f518)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:125 +0xcc
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedSchemaFor(0x4000116120, {0x40004829a0, {0x40005c3a50, 0xd}})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/parser.go:193 +0x1e8
sigs.k8s.io/controller-tools/pkg/crd.(*schemaContext).requestSchema(0x40016d6a80?, {0x4000351a40?, 0x8e6a4b?}, {0x40005c3a50?, 0xd?})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:108 +0xd8
sigs.k8s.io/controller-tools/pkg/crd.namedToSchema(0x40016d6a80, 0x400050ec18)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:292 +0x1bc
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x40016d6a80, {0xa38598, 0x400050ec18})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:199 +0xec
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x40016d6a80, {0xa385f8, 0x400050ec30})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:205 +0xb4
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0x400186fda8, 0x400050ede0)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:455 +0xa3c
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x400186fda8, {0xa38538, 0x400050ede0})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:207 +0x90
sigs.k8s.io/controller-tools/pkg/crd.infoToSchema(0x400186fda8)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:125 +0xcc
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedSchemaFor(0x4000116120, {0x40004827c0, {0x40004f15d8, 0x11}})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/parser.go:193 +0x1e8
sigs.k8s.io/controller-tools/pkg/crd.(*schemaContext).requestSchema(0x4000351b00?, {0x0?, 0x8e6a4b?}, {0x40004f15d8?, 0x0?})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:108 +0xd8
sigs.k8s.io/controller-tools/pkg/crd.localNamedToSchema(0x40016728d0, 0x400007dae0)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:275 +0x168
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x40016728d0, {0xa38568, 0x400007dae0})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:197 +0xd0
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0x40018705f8, 0x400050e708)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:455 +0xa3c
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x40018705f8, {0xa38538, 0x400050e708})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:207 +0x90
sigs.k8s.io/controller-tools/pkg/crd.infoToSchema(0x40018705f8)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/schema.go:125 +0xcc
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedSchemaFor(0x4000116120, {0x40004827c0, {0x4000697540, 0xd}})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/parser.go:193 +0x1e8
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedFlattenedSchemaFor(0x4000116120, {0x40004827c0, {0x4000697540, 0xd}})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/parser.go:205 +0x9c
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedCRDFor(0x4000116120, {{0x400089400e, 0x9}, {0x4000697540, 0xd}}, 0x0)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/spec.go:93 +0x3d8
sigs.k8s.io/controller-tools/pkg/crd.Generator.Generate({0x0, 0x0, 0x0, {0x0, 0x0, 0x0}, 0x0, {0x0, 0x0}, {0x0, ...}, ...}, ...)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/crd/gen.go:182 +0x464
sigs.k8s.io/controller-tools/pkg/genall.(*Runtime).Run(0x40000cb0e0)
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/pkg/genall/genall.go:272 +0x21c
main.main.func1(0x4000272200?, {0x40002c1b30?, 0x4?, 0x8e4bdc?})
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go:176 +0x64
github.com/spf13/cobra.(*Command).execute(0x4000282c08, {0x4000032110, 0x3, 0x3})
        /src/pkg/k8s/vendor/github.com/spf13/cobra/command.go:985 +0x834
github.com/spf13/cobra.(*Command).ExecuteC(0x4000282c08)
        /src/pkg/k8s/vendor/github.com/spf13/cobra/command.go:1117 +0x344
github.com/spf13/cobra.(*Command).Execute(...)
        /src/pkg/k8s/vendor/github.com/spf13/cobra/command.go:1041
main.main()
        /src/pkg/k8s/vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go:200 +0x290
exit status 2

You can use the project I'm working on for repro https://github.com/cilium/tetragon/actions/runs/10808612794/job/29981972633?pr=2800. Basically clone the project with that branch and run make in pkg/k8s.

[sbueringer]

Thx for reporting. That sounds pretty bad

[sbueringer]

If someone has time to take a look at this feel free to go ahead / open a PR

/help

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In response to this:

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/help

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[sbueringer]

@mtardy You are compiling controller-gen yourself, right?

Does the published binary work? (https://github.com/kubernetes-sigs/controller-tools/releases/tag/v0.16.2)

[mtardy]

@mtardy You are compiling controller-gen yourself, right?

Does the published binary work? (https://github.com/kubernetes-sigs/controller-tools/releases/tag/v0.16.2)

yep I have it vendored and use it. I would assume the published binary to work since it's built with 1.22

controller-tools/go.mod

Line 3 in c69110a

go 1.22.0

I can try however :).

Thx for reporting. That sounds pretty bad

I hope I'm not too alarming here if the issue is based on my config (I saw #492). But the fact that this thing only breaks when I bump the Go version in the go.mod directive, and that Golang has an entry in the 1.23 changelog related to this makes me think it can be a general issue.

[mtardy]

Okay I have a minimal reproducer and a fix, I'll post a PR just after (EDIT: here), here's how to reproduce the issue:

1. Create a a repro directory mkdir repro and put repro.go inside of it with:

   // +groupName=repro.io
   package repro
   
   import (
   	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
   )
   
   type Repro struct {
   	metav1.TypeMeta   `json:",inline"`
   	metav1.ObjectMeta `json:"metadata"`
   
   	Reproducer StringAlias `json:"reproducer"`
   }
   
   type StringAlias = string

2. Bump the go directive to Go 1.23.0 in go.mod:

   diff --git a/go.mod b/go.mod
   index 790a5a11..c9e19176 100644
   --- a/go.mod
   +++ b/go.mod
   @@ -1,6 +1,6 @@
    module sigs.k8s.io/controller-tools
   
   -go 1.22.0
   + go 1.23.0

3. Run controller-gen with:

   go run ./cmd/controller-gen/ crd paths=./repro

You should see something similar to:

panic: interface conversion: types.Type is *types.Alias, not *types.Named

goroutine 1 [running]:
sigs.k8s.io/controller-tools/pkg/crd.localNamedToSchema(0x4001315f50, 0x40003918e0)
        /home/mtardy.linux/controller-tools/pkg/crd/schema.go:258 +0x3bc
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x4001315f50, {0xa391e8, 0x40003918e0})
        /home/mtardy.linux/controller-tools/pkg/crd/schema.go:197 +0xd0
sigs.k8s.io/controller-tools/pkg/crd.structToSchema(0x40009ee5f8, 0x400000e300)
        /home/mtardy.linux/controller-tools/pkg/crd/schema.go:436 +0x7d8
sigs.k8s.io/controller-tools/pkg/crd.typeToSchema(0x40009ee5f8, {0xa391b8, 0x400000e300})
        /home/mtardy.linux/controller-tools/pkg/crd/schema.go:207 +0x90
sigs.k8s.io/controller-tools/pkg/crd.infoToSchema(0x40000505f8)
        /home/mtardy.linux/controller-tools/pkg/crd/schema.go:125 +0xcc
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedSchemaFor(0x400009a120, {0x4000207b80, {0x40002c2540, 0x5}})
        /home/mtardy.linux/controller-tools/pkg/crd/parser.go:193 +0x1e8
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedFlattenedSchemaFor(0x400009a120, {0x4000207b80, {0x40002c2540, 0x5}})
        /home/mtardy.linux/controller-tools/pkg/crd/parser.go:205 +0x9c
sigs.k8s.io/controller-tools/pkg/crd.(*Parser).NeedCRDFor(0x400009a120, {{0x4000185a06, 0x8}, {0x40002c2540, 0x5}}, 0x0)
        /home/mtardy.linux/controller-tools/pkg/crd/spec.go:93 +0x3d8
sigs.k8s.io/controller-tools/pkg/crd.Generator.Generate({0x0, 0x0, 0x0, {0x0, 0x0, 0x0}, 0x0, {0x0, 0x0}, {0x0, ...}, ...}, ...)
        /home/mtardy.linux/controller-tools/pkg/crd/gen.go:182 +0x464
sigs.k8s.io/controller-tools/pkg/genall.(*Runtime).Run(0x400015cbd0)
        /home/mtardy.linux/controller-tools/pkg/genall/genall.go:272 +0x21c
main.main.func1(0x40002a2200?, {0x40002d9ad0?, 0x4?, 0x8e519c?})
        /home/mtardy.linux/controller-tools/cmd/controller-gen/main.go:176 +0x64
github.com/spf13/cobra.(*Command).execute(0x40002aec08, {0x4000136090, 0x3, 0x3})
        /home/mtardy.linux/go/pkg/mod/github.com/spf13/cobra@v1.8.1/command.go:985 +0x834
github.com/spf13/cobra.(*Command).ExecuteC(0x40002aec08)
        /home/mtardy.linux/go/pkg/mod/github.com/spf13/cobra@v1.8.1/command.go:1117 +0x344
github.com/spf13/cobra.(*Command).Execute(...)
        /home/mtardy.linux/go/pkg/mod/github.com/spf13/cobra@v1.8.1/command.go:1041
main.main()
        /home/mtardy.linux/controller-tools/cmd/controller-gen/main.go:200 +0x290
exit status 2