From fee8ab50ffbbc64807c8db106f9ae04ff4874d45 Mon Sep 17 00:00:00 2001
From: Tam Mach <sayboras@yahoo.com>
Date: Fri, 20 Sep 2024 20:28:53 +0700
Subject: [PATCH] Preserve existing behavior with go1.22/1.23 alias type
 parsing

This is the manual backport of the below PR to v1.

Relates: https://github.com/kubernetes/gengo/pull/281
---
 parser/parse.go         |  9 ++++++++-
 parser/parse_122.go     | 33 +++++++++++++++++++++++++++++++++
 parser/parse_pre_122.go | 30 ++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 parser/parse_122.go
 create mode 100644 parser/parse_pre_122.go

diff --git a/parser/parse.go b/parser/parse.go
index bbd71929..8b2ae58b 100644
--- a/parser/parse.go
+++ b/parser/parse.go
@@ -33,8 +33,9 @@ import (
 	"sort"
 	"strings"
 
-	"k8s.io/gengo/types"
 	"k8s.io/klog/v2"
+
+	"k8s.io/gengo/types"
 )
 
 // This clarifies when a pkg path has been canonicalized.
@@ -718,6 +719,12 @@ func (b *Builder) walkType(u types.Universe, useName *types.Name, in tc.Type) *t
 		name = *useName
 	}
 
+	// Handle alias types conditionally on go1.22+.
+	// Inline this once the minimum supported version is go1.22
+	if out := b.walkAliasType(u, in); out != nil {
+		return out
+	}
+
 	switch t := in.(type) {
 	case *tc.Struct:
 		out := u.Type(name)
diff --git a/parser/parse_122.go b/parser/parse_122.go
new file mode 100644
index 00000000..94a107e6
--- /dev/null
+++ b/parser/parse_122.go
@@ -0,0 +1,33 @@
+//go:build go1.22
+// +build go1.22
+
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package parser
+
+import (
+	gotypes "go/types"
+
+	"k8s.io/gengo/types"
+)
+
+func (b *Builder) walkAliasType(u types.Universe, in gotypes.Type) *types.Type {
+	if t, isAlias := in.(*gotypes.Alias); isAlias {
+		return b.walkType(u, nil, gotypes.Unalias(t))
+	}
+	return nil
+}
diff --git a/parser/parse_pre_122.go b/parser/parse_pre_122.go
new file mode 100644
index 00000000..6f62100c
--- /dev/null
+++ b/parser/parse_pre_122.go
@@ -0,0 +1,30 @@
+//go:build !go1.22
+// +build !go1.22
+
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package parser
+
+import (
+	gotypes "go/types"
+
+	"k8s.io/gengo/v2/types"
+)
+
+func (p *Parser) walkAliasType(u types.Universe, in gotypes.Type) *types.Type {
+	return nil
+}