Permit specifying build tags for analysis (#252)

Fixes #251

cmd/wire/main.go

@@ -100,6 +100,7 @@ func newGenerateOptions(headerFile string) (*wire.GenerateOptions, error) {
 type genCmd struct {
 	headerFile     string
 	prefixFileName string
+	tags           string
 }
 
 func (*genCmd) Name() string { return "gen" }
@@ -117,6 +118,7 @@ func (*genCmd) Usage() string {
 func (cmd *genCmd) SetFlags(f *flag.FlagSet) {
 	f.StringVar(&cmd.headerFile, "header_file", "", "path to file to insert as a header in wire_gen.go")
 	f.StringVar(&cmd.prefixFileName, "output_file_prefix", "", "string to prepend to output file names.")
+	f.StringVar(&cmd.tags, "tags", "", "append build tags to the default wirebuild")
 }
 
 func (cmd *genCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
@@ -132,6 +134,7 @@ func (cmd *genCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interfa
 	}
 
 	opts.PrefixOutputFile = cmd.prefixFileName
+	opts.Tags = cmd.tags
 
 	outs, errs := wire.Generate(ctx, wd, os.Environ(), packages(f), opts)
 	if len(errs) > 0 {
@@ -169,6 +172,7 @@ func (cmd *genCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interfa
 
 type diffCmd struct {
 	headerFile string
+	tags       string
 }
 
 func (*diffCmd) Name() string { return "diff" }
@@ -189,6 +193,7 @@ func (*diffCmd) Usage() string {
 }
 func (cmd *diffCmd) SetFlags(f *flag.FlagSet) {
 	f.StringVar(&cmd.headerFile, "header_file", "", "path to file to insert as a header in wire_gen.go")
+	f.StringVar(&cmd.tags, "tags", "", "append build tags to the default wirebuild")
 }
 func (cmd *diffCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
 	const (
@@ -206,6 +211,8 @@ func (cmd *diffCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interf
 		return subcommands.ExitFailure
 	}
 
+	opts.Tags = cmd.tags
+
 	outs, errs := wire.Generate(ctx, wd, os.Environ(), packages(f), opts)
 	if len(errs) > 0 {
 		logErrors(errs)
@@ -253,7 +260,9 @@ func (cmd *diffCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interf
 	return subcommands.ExitSuccess
 }
 
-type showCmd struct{}
+type showCmd struct {
+	tags string
+}
 
 func (*showCmd) Name() string { return "show" }
 func (*showCmd) Synopsis() string {
@@ -270,14 +279,16 @@ func (*showCmd) Usage() string {
   If no packages are listed, it defaults to ".".
 `
 }
-func (*showCmd) SetFlags(_ *flag.FlagSet) {}
-func (*showCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+func (cmd *showCmd) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&cmd.tags, "tags", "", "append build tags to the default wirebuild")
+}
+func (cmd *showCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
 	wd, err := os.Getwd()
 	if err != nil {
 		log.Println("failed to get working directory: ", err)
 		return subcommands.ExitFailure
 	}
-	info, errs := wire.Load(ctx, wd, os.Environ(), packages(f))
+	info, errs := wire.Load(ctx, wd, os.Environ(), cmd.tags, packages(f))
 	if info != nil {
 		keys := make([]wire.ProviderSetID, 0, len(info.Sets))
 		for k := range info.Sets {
@@ -341,14 +352,16 @@ func (*showCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{
 	return subcommands.ExitSuccess
 }
 
-type checkCmd struct{}
+type checkCmd struct {
+	tags string
+}
 
 func (*checkCmd) Name() string { return "check" }
 func (*checkCmd) Synopsis() string {
 	return "print any Wire errors found"
 }
 func (*checkCmd) Usage() string {
-	return `check [packages]
+	return `check [-tags tag,list] [packages]
 
   Given one or more packages, check prints any type-checking or Wire errors
   found with top-level variable provider sets or injector functions.
@@ -356,14 +369,16 @@ func (*checkCmd) Usage() string {
   If no packages are listed, it defaults to ".".
 `
 }
-func (*checkCmd) SetFlags(_ *flag.FlagSet) {}
-func (*checkCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+func (cmd *checkCmd) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&cmd.tags, "tags", "", "append build tags to the default wirebuild")
+}
+func (cmd *checkCmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
 	wd, err := os.Getwd()
 	if err != nil {
 		log.Println("failed to get working directory: ", err)
 		return subcommands.ExitFailure
 	}
-	_, errs := wire.Load(ctx, wd, os.Environ(), packages(f))
+	_, errs := wire.Load(ctx, wd, os.Environ(), cmd.tags, packages(f))
 	if len(errs) > 0 {
 		logErrors(errs)
 		log.Println("error loading packages")

internal/wire/parse.go

@@ -248,8 +248,8 @@ type Field struct {
 // env is nil or empty, it is interpreted as an empty set of variables.
 // In case of duplicate environment variables, the last one in the list
 // takes precedence.
-func Load(ctx context.Context, wd string, env []string, patterns []string) (*Info, []error) {
-	pkgs, errs := load(ctx, wd, env, patterns)
+func Load(ctx context.Context, wd string, env []string, tags string, patterns []string) (*Info, []error) {
+	pkgs, errs := load(ctx, wd, env, tags, patterns)
 	if len(errs) > 0 {
 		return nil, errs
 	}
@@ -349,7 +349,7 @@ func Load(ctx context.Context, wd string, env []string, patterns []string) (*Inf
 // env is nil or empty, it is interpreted as an empty set of variables.
 // In case of duplicate environment variables, the last one in the list
 // takes precedence.
-func load(ctx context.Context, wd string, env []string, patterns []string) ([]*packages.Package, []error) {
+func load(ctx context.Context, wd string, env []string, tags string, patterns []string) ([]*packages.Package, []error) {
 	cfg := &packages.Config{
 		Context:    ctx,
 		Mode:       packages.LoadAllSyntax,
@@ -358,6 +358,9 @@ func load(ctx context.Context, wd string, env []string, patterns []string) ([]*p
 		BuildFlags: []string{"-tags=wireinject"},
 		// TODO(light): Use ParseFile to skip function bodies and comments in indirect packages.
 	}
+	if len(tags) > 0 {
+		cfg.BuildFlags[0] += " " + tags
+	}
 	escaped := make([]string, len(patterns))
 	for i := range patterns {
 		escaped[i] = "pattern=" + patterns[i]

internal/wire/wire.go

@@ -65,6 +65,7 @@ type GenerateOptions struct {
 	// Header will be inserted at the start of each generated file.
 	Header           []byte
 	PrefixOutputFile string
+	Tags             string
 }
 
 // Generate performs dependency injection for the packages that match the given
@@ -83,7 +84,7 @@ func Generate(ctx context.Context, wd string, env []string, patterns []string, o
 	if opts == nil {
 		opts = &GenerateOptions{}
 	}
-	pkgs, errs := load(ctx, wd, env, patterns)
+	pkgs, errs := load(ctx, wd, env, opts.Tags, patterns)
 	if len(errs) > 0 {
 		return nil, errs
 	}
@@ -103,7 +104,7 @@ func Generate(ctx context.Context, wd string, env []string, patterns []string, o
 			continue
 		}
 		copyNonInjectorDecls(g, injectorFiles, pkg.TypesInfo)
-		goSrc := g.frame()
+		goSrc := g.frame(opts.Tags)
 		if len(opts.Header) > 0 {
 			goSrc = append(opts.Header, goSrc...)
 		}
@@ -257,13 +258,16 @@ func newGen(pkg *packages.Package) *gen {
 }
 
 // frame bakes the built up source body into an unformatted Go source file.
-func (g *gen) frame() []byte {
+func (g *gen) frame(tags string) []byte {
 	if g.buf.Len() == 0 {
 		return nil
 	}
 	var buf bytes.Buffer
+	if len(tags) > 0 {
+		tags = fmt.Sprintf(" gen -tags \"%s\"", tags)
+	}
 	buf.WriteString("// Code generated by Wire. DO NOT EDIT.\n\n")
-	buf.WriteString("//go:generate wire\n")
+	buf.WriteString("//go:generate wire" + tags + "\n")
 	buf.WriteString("//+build !wireinject\n\n")
 	buf.WriteString("package ")
 	buf.WriteString(g.pkg.Name)