Added support for build tags to generated code

README.md

@@ -23,6 +23,10 @@ To specify a pointer receiver for the method, an optional `--pointer-receiver`
 boolean flag can be specified. The flag will also govern whether the return
 type is a pointer as well.
 
+To specify build tags in the generated code, an optional `--tags` comma separated
+list flag can be specified. The flag will add all items as build tags to the
+generated code.
+
 It might also be desirable to skip deeply copying certain fields, slice
 members, or map members. To achieve that, selectors can be specified in the
 optional comma-separated `--skip` flag. Multiple `--skip` flags can be
@@ -64,12 +68,13 @@ deep-copy <flags> github.com/globusdigital/deep-copy/some/sub/packages
 Here is the full set of supported flags:
 
 ```bash
-deep-copy \ 
+deep-copy \
   [-o /output/path.go] \
   [--method DeepCopy] \
   [--pointer-receiver] \
-  [--skip Selector1,Selector.Two --skip Selector2[i], Selector.Three[k]] 
-  [--type Type1 --type Type2\ \ 
+  [--skip Selector1,Selector.Two --skip Selector2[i], Selector.Three[k]]
+  [--type Type1 --type Type2\ \
+  [--tags mytag,anotherTag ] \ \
   /path/to/package/containing/type
 ```
 

deepcopy/generator.go

@@ -31,19 +31,21 @@ type Generator struct {
 	maxDepth   int
 	methodName string
 	skipLists  SkipLists
+	buildTags  []string
 
 	imports map[string]string
 	fns     [][]byte
 }
 
 func NewGenerator(
-	isPtrRecv bool, methodName string, skipLists SkipLists, maxDepth int,
+	isPtrRecv bool, methodName string, skipLists SkipLists, maxDepth int, buildTags []string,
 ) Generator {
 	return Generator{
 		isPtrRecv:  isPtrRecv,
 		methodName: methodName,
 		maxDepth:   maxDepth,
 		skipLists:  skipLists,
+		buildTags:  buildTags,
 
 		imports: map[string]string{},
 		fns:     [][]byte{},
@@ -134,6 +136,10 @@ func (g Generator) generateFile(w io.Writer, p *packages.Package) error {
 
 	fmt.Fprintf(&file, "// Code generated by %s; DO NOT EDIT.\n\npackage %s\n\n", strings.Join(os.Args, " "), p.Name)
 
+	for _, tag := range g.buildTags {
+		fmt.Fprintf(&file, "//go:build %s\n// +build %s\n", tag, tag)
+	}
+
 	if len(g.imports) > 0 {
 		file.WriteString("import (\n")
 		for name, path := range g.imports {

main.go

@@ -18,9 +18,10 @@ var (
 	maxDepthF        = flag.Int("maxdepth", 0, "max depth of deep copying")
 	methodF          = flag.String("method", "DeepCopy", "deep copy method name")
 
-	typesF  typesVal
-	skipsF  skipsVal
-	outputF outputVal
+	typesF     typesVal
+	skipsF     skipsVal
+	outputF    outputVal
+	buildTagsF buildTagsVal
 )
 
 type typesVal []string
@@ -106,10 +107,22 @@ func (f *outputVal) Open() (io.WriteCloser, error) {
 	return f.file, nil
 }
 
+type buildTagsVal []string
+
+func (b *buildTagsVal) String() string {
+	return strings.Join(*b, ",")
+}
+
+func (b *buildTagsVal) Set(v string) error {
+	*b = append(*b, v)
+	return nil
+}
+
 func init() {
 	flag.Var(&typesF, "type", "the concrete type. Multiple flags can be specified")
 	flag.Var(&skipsF, "skip", "comma-separated field/slice/map selectors to shallow copy. Multiple flags can be specified")
 	flag.Var(&outputF, "o", "the output file to write to. Defaults to STDOUT")
+	flag.Var(&buildTagsF, "tags", "comma-separated build tags to add to generated file")
 }
 
 func main() {
@@ -124,7 +137,7 @@ func main() {
 	}
 
 	sl := deepcopy.SkipLists(skipsF)
-	generator := deepcopy.NewGenerator(*pointerReceiverF, *methodF, sl, *maxDepthF)
+	generator := deepcopy.NewGenerator(*pointerReceiverF, *methodF, sl, *maxDepthF, buildTagsF)
 
 	output, err := outputF.Open()
 	if err != nil {

main_test.go

@@ -11,14 +11,15 @@ import (
 
 func Test_run(t *testing.T) {
 	tests := []struct {
-		name     string
-		types    typesVal
-		path     string
-		pointer  bool
-		skips    skipsVal
-		maxdepth int
-		method   string
-		want     []byte
+		name      string
+		types     typesVal
+		path      string
+		pointer   bool
+		skips     skipsVal
+		maxdepth  int
+		buildTags []string
+		method    string
+		want      []byte
 	}{
 		{name: "foo", types: typesVal{"Foo"}, path: "./testdata", want: []byte(FooFile)},
 		{name: "foo - pointer", types: typesVal{"Foo"}, pointer: true, path: "./testdata", want: []byte(FooPointerFile)},
@@ -43,6 +44,7 @@ func Test_run(t *testing.T) {
 		{name: "issue 15, parent has child pointer, pointer receiver", pointer: true, types: typesVal{"ParentHasChildPointer", "Child"}, path: "./testdata", want: []byte(I15ParentHasChildPointerPointerRecv)},
 		{name: "issue 17, with maxdepth", types: typesVal{"Depth1"}, pointer: true, maxdepth: 2, path: "./testdata", want: []byte(Issue17MaxDepth)},
 		{name: "alias import", types: typesVal{"Data"}, path: "./testdata/import_alias", want: []byte(AliasImport)},
+		{name: "using build tags", types: typesVal{"Foo"}, path: "./testdata", buildTags: []string{"!myTag", "anotherOne"}, want: []byte(FooFileBuildTags)},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -51,7 +53,7 @@ func Test_run(t *testing.T) {
 				method = tt.method
 			}
 			g := deepcopy.NewGenerator(tt.pointer, method,
-				deepcopy.SkipLists(tt.skips), tt.maxdepth)
+				deepcopy.SkipLists(tt.skips), tt.maxdepth, tt.buildTags)
 			var buf bytes.Buffer
 			err := run(g, &buf, tt.path, tt.types)
 			if err != nil {
@@ -588,4 +590,42 @@ func (o Data) DeepCopy() Data {
 	}
 	return cp
 }`
+
+	FooFileBuildTags = `// Code generated by deep-copy; DO NOT EDIT.
+
+//go:build !myTag
+//go:build anotherOne
+// +build !myTag
+// +build anotherOne
+
+package testdata
+
+// DeepCopy generates a deep copy of Foo
+//
+func (o Foo) DeepCopy() Foo {
+	var cp Foo = o
+	if o.Map != nil {
+		cp.Map = make(map[string]*Bar, len(o.Map))
+		for k2, v2 := range o.Map {
+			var cp_Map_v2 *Bar
+			if v2 != nil {
+				cp_Map_v2 = new(Bar)
+				*cp_Map_v2 = *v2
+				if v2.Slice != nil {
+					cp_Map_v2.Slice = make([]string, len(v2.Slice))
+					copy(cp_Map_v2.Slice, v2.Slice)
+				}
+			}
+			cp.Map[k2] = cp_Map_v2
+		}
+	}
+	if o.ch != nil {
+		cp.ch = make(chan float32, cap(o.ch))
+	}
+	if o.baz.StringPointer != nil {
+		cp.baz.StringPointer = new(string)
+		*cp.baz.StringPointer = *o.baz.StringPointer
+	}
+	return cp
+}`
 )