Fix prefix dropper in Go codegen (#56041)

pkg/codegen/coremodel.go

@@ -21,6 +21,7 @@ import (
 	"github.com/grafana/grafana/pkg/cuectx"
 	"github.com/grafana/thema"
 	"github.com/grafana/thema/encoding/openapi"
+	"golang.org/x/tools/go/ast/astutil"
 )
 
 // CoremodelDeclaration contains the results of statically analyzing a Grafana
@@ -279,30 +280,77 @@ type prefixDropper struct {
 	rxpsuff *regexp.Regexp
 }
 
-func makePrefixDropper(str, base string) prefixDropper {
-	return prefixDropper{
+func makePrefixDropper(str, base string) astutil.ApplyFunc {
+	return (&prefixDropper{
 		str:     str,
 		base:    base,
 		rxpsuff: regexp.MustCompile(fmt.Sprintf(`%s([a-zA-Z_]*)`, str)),
 		rxp:     regexp.MustCompile(fmt.Sprintf(`%s([\s.,;-])`, str)),
-	}
+	}).applyfunc
 }
 
-func (d prefixDropper) Visit(n ast.Node) ast.Visitor {
+func depoint(e ast.Expr) ast.Expr {
+	if star, is := e.(*ast.StarExpr); is {
+		return star.X
+	}
+	return e
+}
+
+func (d prefixDropper) applyfunc(c *astutil.Cursor) bool {
+	n := c.Node()
+
+	// fmt.Printf("%T %s\n", c.Node(), ast.Print(nil, c.Node()))
 	switch x := n.(type) {
-	case *ast.Ident:
-		if x.Name != d.str {
-			x.Name = strings.TrimPrefix(x.Name, d.str)
-		} else {
-			x.Name = d.base
+	case *ast.ValueSpec:
+		// fmt.Printf("%T %s\n", c.Node(), ast.Print(nil, c.Node()))
+		d.handleExpr(x.Type)
+		for _, id := range x.Names {
+			d.do(id)
 		}
+	case *ast.TypeSpec:
+		// Always do typespecs
+		d.do(x.Name)
+	case *ast.Field:
+		// Don't rename struct fields. We just want to rename type declarations, and
+		// field value specifications that reference those types.
+		d.handleExpr(x.Type)
+		// return false
+
 	case *ast.CommentGroup:
 		for _, c := range x.List {
 			c.Text = d.rxp.ReplaceAllString(c.Text, d.base+"$1")
 			c.Text = d.rxpsuff.ReplaceAllString(c.Text, "$1")
 		}
 	}
-	return d
+	return true
+}
+
+func (d prefixDropper) handleExpr(e ast.Expr) {
+	// Deref a StarExpr, if there is one
+	expr := depoint(e)
+	switch x := expr.(type) {
+	case *ast.Ident:
+		d.do(x)
+	case *ast.ArrayType:
+		if id, is := depoint(x.Elt).(*ast.Ident); is {
+			d.do(id)
+		}
+	case *ast.MapType:
+		if id, is := depoint(x.Key).(*ast.Ident); is {
+			d.do(id)
+		}
+		if id, is := depoint(x.Value).(*ast.Ident); is {
+			d.do(id)
+		}
+	}
+}
+
+func (d prefixDropper) do(n *ast.Ident) {
+	if n.Name != d.str {
+		n.Name = strings.TrimPrefix(n.Name, d.str)
+	} else {
+		n.Name = d.base
+	}
 }
 
 // GenerateCoremodelRegistry produces Go files that define a registry with