Remove unused parser resource plumbing

internal/cobra/parse.go

@@ -4,7 +4,6 @@ package cobra
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"io"
 	"strconv"
@@ -35,8 +34,7 @@ func Prepare(root *commandmeta.Command, options commandmeta.ParseOptions) *Sessi
 	session.metadata = root
 	session.flagAliases = append([]commandmeta.FlagAlias(nil), options.FlagAliases...)
 	session.flagAliasesForPath = options.FlagAliasesForPath
-	options = normalizeOptions(options)
-	session.root, session.declarations = buildTree(root, options)
+	session.root, session.declarations = buildTree(root)
 	return session
 }
 
@@ -289,23 +287,7 @@ func Parse(root *commandmeta.Command, argv []string, options commandmeta.ParseOp
 	return Prepare(root, options).Parse(argv)
 }
 
-func normalizeOptions(options commandmeta.ParseOptions) commandmeta.ParseOptions {
-	if options.Context == nil {
-		options.Context = context.Background()
-	}
-	if options.In == nil {
-		options.In = strings.NewReader("")
-	}
-	if options.Out == nil {
-		options.Out = io.Discard
-	}
-	if options.Err == nil {
-		options.Err = io.Discard
-	}
-	return options
-}
-
-func buildTree(root *commandmeta.Command, options commandmeta.ParseOptions) (*spfcobra.Command, map[*spfcobra.Command]*commandmeta.Command) {
+func buildTree(root *commandmeta.Command) (*spfcobra.Command, map[*spfcobra.Command]*commandmeta.Command) {
 	nodes := make(map[*spfcobra.Command]*commandmeta.Command)
 	var build func(*commandmeta.Command) *spfcobra.Command
 	build = func(declaration *commandmeta.Command) *spfcobra.Command {
@@ -321,10 +303,8 @@ func buildTree(root *commandmeta.Command, options commandmeta.ParseOptions) (*sp
 		if declaration.Runnable {
 			backend.Run = func(*spfcobra.Command, []string) {}
 		}
-		backend.SetContext(options.Context)
-		backend.SetIn(options.In)
-		backend.SetOut(options.Out)
-		backend.SetErr(options.Err)
+		backend.SetOut(io.Discard)
+		backend.SetErr(io.Discard)
 		backend.SetHelpFunc(func(*spfcobra.Command, []string) {})
 		backend.SetFlagErrorFunc(func(_ *spfcobra.Command, err error) error { return err })
 		backend.SetUsageTemplate(usageTemplate)

internal/cobra/parse_test.go

@@ -1,8 +1,6 @@
 package cobra
 
 import (
-	"bytes"
-	"context"
 	"fmt"
 	"io"
 	"reflect"
@@ -182,7 +180,7 @@ func TestParseReturnsNeutralFailuresAndFreshState(t *testing.T) {
 	tree := &Command{Name: "app", Children: []*Command{
 		{Name: "run", Runnable: true, Flags: []Flag{{Name: "value"}}},
 	}}
-	options := ParseOptions{Context: context.Background(), In: strings.NewReader("unused"), Out: io.Discard, Err: io.Discard}
+	options := ParseOptions{}
 	first := Parse(tree, []string{"run", "--value=old"}, options)
 	second := Parse(tree, []string{"run"}, options)
 	if first.Failure != nil || second.Failure != nil {
@@ -247,8 +245,7 @@ func TestSelectedPathsResolveThroughBackendParents(t *testing.T) {
 
 func TestSessionReusesTreeForParseHelpAndUsageWithFreshState(t *testing.T) {
 	tree := &Command{Name: "app", Children: []*Command{{Name: "run", Runnable: true, Flags: []Flag{{Name: "value"}}}}}
-	var output, errors bytes.Buffer
-	session := Prepare(tree, ParseOptions{Context: context.Background(), Out: &output, Err: &errors})
+	session := Prepare(tree, ParseOptions{})
 	first := session.Parse([]string{"run", "--value=old"})
 	if first.Failure != nil || !reflect.DeepEqual(first.FlagValues, [][]string{{"old"}}) {
 		t.Fatalf("first session parse = %#v", first)
@@ -261,19 +258,15 @@ func TestSessionReusesTreeForParseHelpAndUsageWithFreshState(t *testing.T) {
 	if failure != nil || !strings.Contains(line, "run") {
 		t.Fatalf("session usage = %q, %v", line, failure)
 	}
-	if output.Len() != 0 || errors.Len() != 0 {
-		t.Fatalf("help escaped session delivery control: out=%q err=%q", output.String(), errors.String())
+	if session.root.OutOrStdout() != io.Discard || session.root.ErrOrStderr() != io.Discard {
+		t.Fatal("backend destinations are not discarded")
 	}
 
-	var secondOutput, secondErrors bytes.Buffer
-	second := Prepare(tree, ParseOptions{Context: context.Background(), Out: &secondOutput, Err: &secondErrors})
+	second := Prepare(tree, ParseOptions{})
 	secondResult := second.Parse([]string{"run"})
 	if secondResult.Failure != nil || !reflect.DeepEqual(secondResult.FlagValues, [][]string{nil}) {
 		t.Fatalf("fresh session state = %#v", secondResult)
 	}
-	if output.Len() != 0 || errors.Len() != 0 || secondOutput.Len() != 0 || secondErrors.Len() != 0 {
-		t.Fatal("prepared session streams were unexpectedly used")
-	}
 }
 
 func TestMissingSessionTreeReturnsNeutralFailures(t *testing.T) {

internal/cobra/performance_test.go

@@ -1,9 +1,7 @@
 package cobra
 
 import (
-	"context"
 	"fmt"
-	"io"
 	"testing"
 )
 
@@ -11,7 +9,7 @@ func BenchmarkPerformanceParse(b *testing.B) {
 	wide := performanceFlatTree(128)
 	wideArgs := []string{"wide127"}
 	deep, deepArgs := performanceNestedTree(24)
-	options := ParseOptions{Context: context.Background(), Out: io.Discard, Err: io.Discard}
+	options := ParseOptions{}
 
 	for _, benchmark := range []struct {
 		name string
@@ -41,7 +39,7 @@ func BenchmarkPerformanceParse(b *testing.B) {
 func BenchmarkPerformanceSessionParseAndHelp(b *testing.B) {
 	root := performanceFlatTree(8)
 	args := []string{"wide007"}
-	session := Prepare(root, ParseOptions{Context: context.Background(), Out: io.Discard, Err: io.Discard})
+	session := Prepare(root, ParseOptions{})
 	result := session.Parse(args)
 	if result.Failure != nil {
 		b.Fatalf("fixture parse failed: %s", result.Failure.Message)

internal/commandmeta/metadata.go

@@ -2,11 +2,6 @@
 // its command-line backend.
 package commandmeta
 
-import (
-	"context"
-	"io"
-)
-
 // Key identifies one command inside one routing snapshot.
 type Key uint64
 
@@ -181,14 +176,10 @@ type Result struct {
 	Failure         *Failure
 }
 
-// ParseOptions makes parser context and streams explicit.
+// ParseOptions selects flag aliases for parser contexts.
 type ParseOptions struct {
 	// FlagAliasesForPath selects aliases for the actual parser context when
 	// routing has not already selected one. It overrides FlagAliases when set.
 	FlagAliasesForPath func([]string) []FlagAlias
-	Context            context.Context
-	In                 io.Reader
-	Out                io.Writer
-	Err                io.Writer
 	FlagAliases        []FlagAlias
 }