pkg/crd: fix alias conversion to schema with gotypesalias=1

This patch will be needed when upgrading to Go 1.23 as type alias now
generate a proper type (instead of directly being the basic type they
alias to), see https://pkg.go.dev/go/types#Alias for more info.

This just reproduces the old behavior by retrieving the underlying type
from the alias. If needed, we could treat alias more gracefully to make
the type ref link now that we have all the type information.

Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>

pkg/crd/schema.go

@@ -242,14 +242,18 @@ func localNamedToSchema(ctx *schemaContext, ident *ast.Ident) *apiext.JSONSchema
 		ctx.pkg.AddError(loader.ErrFromNode(fmt.Errorf("unknown type %s", ident.Name), ident))
 		return &apiext.JSONSchemaProps{}
 	}
+	// This reproduces the behavior we had pre gotypesalias=1 (needed if this
+	// project is compiled with default settings and Go >= 1.23).
+	if aliasInfo, isAlias := typeInfo.(*types.Alias); isAlias {
+		typeInfo = aliasInfo.Underlying()
+	}
 	if basicInfo, isBasic := typeInfo.(*types.Basic); isBasic {
 		typ, fmt, err := builtinToType(basicInfo, ctx.allowDangerousTypes)
 		if err != nil {
 			ctx.pkg.AddError(loader.ErrFromNode(err, ident))
 		}
-		// Check for type aliasing to a basic type. Note that this is no longer
-		// needed with gotypesalias=1 as the above isBasic check is false. See
-		// more https://pkg.go.dev/go/types#Alias:
+		// Check for type aliasing to a basic type for gotypesalias=0. See more
+		// in documentation https://pkg.go.dev/go/types#Alias:
 		// > For gotypesalias=1, alias declarations produce an Alias type.
 		// > Otherwise, the alias information is only in the type name, which
 		// > points directly to the actual (aliased) type.