copy through any unknown data

example/config/todo.graphql

@@ -10,4 +10,3 @@ input NewTodo {
   text: String!
   userId: String!
 }
-

internal/rewrite/rewriter.go

@@ -1,19 +1,22 @@
 package rewrite
 
 import (
+	"bytes"
 	"fmt"
 	"go/ast"
 	"go/token"
 	"io/ioutil"
 	"path/filepath"
 	"strconv"
+	"strings"
 
 	"golang.org/x/tools/go/packages"
 )
 
 type Rewriter struct {
-	pkg   *packages.Package
-	files map[string]string
+	pkg    *packages.Package
+	files  map[string]string
+	copied map[ast.Decl]bool
 }
 
 func New(importPath string) (*Rewriter, error) {
@@ -25,8 +28,9 @@ func New(importPath string) (*Rewriter, error) {
 	}
 
 	return &Rewriter{
-		pkg:   pkgs[0],
-		files: map[string]string{},
+		pkg:    pkgs[0],
+		files:  map[string]string{},
+		copied: map[ast.Decl]bool{},
 	}, nil
 }
 
@@ -80,6 +84,8 @@ func (r *Rewriter) GetMethodBody(structname string, methodname string) string {
 					continue
 				}
 
+				r.copied[d] = true
+
 				return r.getSource(d.Body.Pos()+1, d.Body.End()-1)
 			}
 		}
@@ -88,6 +94,30 @@ func (r *Rewriter) GetMethodBody(structname string, methodname string) string {
 	return ""
 }
 
+func (r *Rewriter) MarkStructCopied(name string) {
+	for _, f := range r.pkg.Syntax {
+		for _, d := range f.Decls {
+			switch d := d.(type) {
+			case *ast.GenDecl:
+				if d.Tok != token.TYPE || len(d.Specs) == 0 {
+					continue
+				}
+
+				spec, isTypeSpec := d.Specs[0].(*ast.TypeSpec)
+				if !isTypeSpec {
+					continue
+				}
+
+				if spec.Name.Name != name {
+					continue
+				}
+
+				r.copied[d] = true
+			}
+		}
+	}
+}
+
 func (r *Rewriter) ExistingImports(filename string) []Import {
 	filename, err := filepath.Abs(filename)
 	if err != nil {
@@ -117,6 +147,41 @@ func (r *Rewriter) ExistingImports(filename string) []Import {
 	return nil
 }
 
+func (r *Rewriter) RemainingSource(filename string) string {
+	filename, err := filepath.Abs(filename)
+	if err != nil {
+		panic(err)
+	}
+	for _, f := range r.pkg.Syntax {
+		pos := r.pkg.Fset.Position(f.Pos())
+
+		if filename != pos.Filename {
+			continue
+		}
+
+		var buf bytes.Buffer
+
+		for _, d := range f.Decls {
+			if r.copied[d] {
+				continue
+			}
+			switch d := d.(type) {
+			case *ast.GenDecl:
+				if d.Tok == token.IMPORT {
+					continue
+				}
+			}
+			fmt.Printf("%T\n", d)
+
+			buf.WriteString(r.getSource(d.Pos(), d.End()))
+			buf.WriteString("\n")
+		}
+
+		return strings.TrimSpace(buf.String())
+	}
+	return ""
+}
+
 type Import struct {
 	Alias      string
 	ImportPath string

plugin/resolvergen/resolver.go

@@ -1,6 +1,7 @@
 package resolvergen
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -94,6 +95,9 @@ func (m *Plugin) generatePerSchema(data *codegen.Data) error {
 				}
 			}
 
+			rewriter.MarkStructCopied(templates.LcFirst(o.Name) + templates.UcFirst(data.Config.Resolver.Type))
+			rewriter.GetMethodBody(data.Config.Resolver.Type, o.Name)
+			fmt.Println(data.Config.Resolver.Type, o.Name)
 			files[fn].Objects = append(files[fn].Objects, o)
 		}
 		for _, f := range o.Fields {
@@ -117,6 +121,10 @@ func (m *Plugin) generatePerSchema(data *codegen.Data) error {
 		}
 	}
 
+	for filename, file := range files {
+		file.RemainingSource = rewriter.RemainingSource(filename)
+	}
+
 	for filename, file := range files {
 		resolverBuild := &ResolverBuild{
 			File:         file,
@@ -166,9 +174,10 @@ type ResolverBuild struct {
 type File struct {
 	// These are separated because the type definition of the resolver object may live in a different file from the
 	//resolver method implementations, for example when extending a type in a different graphql schema file
-	Objects   []*codegen.Object
-	Resolvers []*Resolver
-	imports   []rewrite.Import
+	Objects         []*codegen.Object
+	Resolvers       []*Resolver
+	imports         []rewrite.Import
+	RemainingSource string
 }
 
 func (f *File) Imports() string {

plugin/resolvergen/resolver.gotpl

@@ -32,3 +32,12 @@
 	type {{lcFirst $object.Name}}{{ucFirst $.ResolverType}} struct { *{{$.ResolverType}} }
 {{ end }}
 
+{{ if (ne .RemainingSource "") }}
+    // !!! WARNING !!!
+    // The code below was going to be deleted when updating resolvers. It has been copied here so you have
+    // one last chance to move it out of harms way if you want. There are two reasons this happens:
+	//  - When renaming or deleting a resolver the old code will be put in here. You can safely delete
+	//    it when you're done.
+	//  - You have helper methods in this file. Move them out to keep these resolver files clean.
+	{{ .RemainingSource }}
+{{ end }}