Revert "Introduce zed.Arena (#5118)" and "sort: Fix spill garbage col…

…lection bug (#5239)" (#5278)

This reverts commits ce9626e and
1ffe14f.

A zed.Value allocated by a zed.Arena holds an untyped pointer to the
arena in zed.Value.a, hiding the arena from the garbage collector and
requiring maintenance elsewhere of a typed pointer that lives as long as
the zed.Value.  Failure to do so reliably has so far led to three
distinct panics not caught by automated tests, and more are likely to
appear.

At the same time, arenas haven't produced the anticipated performance
benefit, in part because they introduce new bottlenecks without obvious
fixes.

In this light and given current priorities, time spent fixing arena bugs
isn't well spent, so this change removes zed.Arena.

Makefile

@@ -19,7 +19,7 @@ endif
 #PEG_DEP=peg
 
 vet:
-	@go vet -unsafeptr=false ./...
+	@go vet ./...
 
 fmt:
 	gofmt -s -w .

api/client/request.go

@@ -9,7 +9,6 @@ import (
 	"net/http/httptrace"
 	"time"
 
-	"github.com/brimdata/zed"
 	"github.com/brimdata/zed/api"
 	"github.com/brimdata/zed/zio"
 	"github.com/brimdata/zed/zio/zngio"
@@ -96,9 +95,7 @@ func (r *Request) reader() (io.Reader, error) {
 	}
 	m := zson.NewZNGMarshaler()
 	m.Decorate(zson.StylePackage)
-	arena := zed.NewArena()
-	defer arena.Unref()
-	val, err := m.Marshal(arena, r.Body)
+	val, err := m.Marshal(r.Body)
 	if err != nil {
 		return nil, err
 	}

api/queryio/client.go

@@ -77,9 +77,7 @@ func marshalControl(zctrl *zbuf.Control) (any, error) {
 	if ctrl.Format != zngio.ControlFormatZSON {
 		return nil, fmt.Errorf("unsupported app encoding: %v", ctrl.Format)
 	}
-	arena := zed.NewArena()
-	defer arena.Unref()
-	value, err := zson.ParseValue(zed.NewContext(), arena, string(ctrl.Bytes))
+	value, err := zson.ParseValue(zed.NewContext(), string(ctrl.Bytes))
 	if err != nil {
 		return nil, fmt.Errorf("unable to parse Zed control message: %w (%s)", err, ctrl.Bytes)
 	}

api/queryio/zjson_test.go

@@ -24,9 +24,7 @@ func TestZJSONWriter(t *testing.T) {
 	w := queryio.NewZJSONWriter(&buf)
 	err := w.WriteControl(api.QueryChannelSet{Channel: "main"})
 	require.NoError(t, err)
-	arena := zed.NewArena()
-	defer arena.Unref()
-	err = w.Write(zson.MustParseValue(zed.NewContext(), arena, record))
+	err = w.Write(zson.MustParseValue(zed.NewContext(), record))
 	require.NoError(t, err)
 	err = w.WriteControl(api.QueryChannelEnd{Channel: "main"})
 	require.NoError(t, err)

api/queryio/zng.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"io"
 
-	"github.com/brimdata/zed"
 	"github.com/brimdata/zed/zio"
 	"github.com/brimdata/zed/zio/zngio"
 	"github.com/brimdata/zed/zio/zsonio"
@@ -14,7 +13,6 @@ import (
 type ZNGWriter struct {
 	*zngio.Writer
 	marshaler *zson.MarshalZNGContext
-	arena     *zed.Arena
 }
 
 var _ controlWriter = (*ZJSONWriter)(nil)
@@ -25,13 +23,11 @@ func NewZNGWriter(w io.Writer) *ZNGWriter {
 	return &ZNGWriter{
 		Writer:    zngio.NewWriter(zio.NopCloser(w)),
 		marshaler: m,
-		arena:     zed.NewArena(),
 	}
 }
 
 func (w *ZNGWriter) WriteControl(v interface{}) error {
-	w.arena.Reset()
-	val, err := w.marshaler.Marshal(w.arena, v)
+	val, err := w.marshaler.Marshal(v)
 	if err != nil {
 		return err
 	}

cli/zq/command.go

@@ -143,7 +143,7 @@ func (c *Command) Run(args []string) error {
 	local := storage.NewLocalEngine()
 	var readers []zio.Reader
 	if null {
-		readers = []zio.Reader{zbuf.NewArray(nil, []zed.Value{zed.Null})}
+		readers = []zio.Reader{zbuf.NewArray([]zed.Value{zed.Null})}
 	} else {
 		readers, err = c.inputFlags.Open(ctx, zctx, local, paths, c.stopErr)
 		if err != nil {

cmd/zed/dev/dig/frames/command.go

@@ -77,7 +77,6 @@ func (c *Command) Run(args []string) error {
 type metaReader struct {
 	reader    *reader
 	marshaler *zson.MarshalZNGContext
-	arena     *zed.Arena
 }
 
 var _ zio.Reader = (*metaReader)(nil)
@@ -86,7 +85,6 @@ func newMetaReader(r io.Reader) *metaReader {
 	return &metaReader{
 		reader:    &reader{reader: bufio.NewReader(r)},
 		marshaler: zson.NewZNGMarshaler(),
-		arena:     zed.NewArena(),
 	}
 }
 
@@ -118,8 +116,7 @@ func (m *metaReader) Read() (*zed.Value, error) {
 	if f == nil || err != nil {
 		return nil, err
 	}
-	m.arena.Reset()
-	val, err := m.marshaler.Marshal(m.arena, f)
+	val, err := m.marshaler.Marshal(f)
 	return &val, err
 }
 

cmd/zed/dev/vector/agg/command.go

@@ -62,16 +62,15 @@ func (c *Command) Run(args []string) error {
 		return err
 	}
 	field := args[1]
-	zctx := zed.NewContext()
 	local := storage.NewLocalEngine()
 	cache := vcache.NewCache(local)
-	object, err := cache.Fetch(ctx, zctx, uri, ksuid.Nil)
+	object, err := cache.Fetch(ctx, uri, ksuid.Nil)
 	if err != nil {
 		return err
 	}
 	defer object.Close()
 	//XXX nil puller
-	agg := op.NewCountByString(zctx, nil, field)
+	agg := op.NewCountByString(zed.NewContext(), nil, field)
 	writer, err := c.outputFlags.Open(ctx, local)
 	if err != nil {
 		return err

cmd/zed/dev/vector/copy/command.go

@@ -57,9 +57,8 @@ func (c *Command) Run(args []string) error {
 	if err != nil {
 		return err
 	}
-	zctx := zed.NewContext()
 	local := storage.NewLocalEngine()
-	object, err := vcache.NewObject(ctx, zctx, local, uri)
+	object, err := vcache.NewObject(ctx, local, uri)
 	if err != nil {
 		return err
 	}
@@ -68,7 +67,7 @@ func (c *Command) Run(args []string) error {
 	if err != nil {
 		return err
 	}
-	puller := vam.NewProjection(zctx, object, nil)
+	puller := vam.NewProjection(zed.NewContext(), object, nil)
 	if err := zbuf.CopyPuller(writer, puller); err != nil {
 		writer.Close()
 		return err

cmd/zed/dev/vector/project/command.go

@@ -64,15 +64,14 @@ func (c *Command) Run(args []string) error {
 	for _, dotted := range args[1:] {
 		paths = append(paths, field.Dotted(dotted))
 	}
-	zctx := zed.NewContext()
 	local := storage.NewLocalEngine()
 	cache := vcache.NewCache(local)
-	object, err := cache.Fetch(ctx, zctx, uri, ksuid.Nil)
+	object, err := cache.Fetch(ctx, uri, ksuid.Nil)
 	if err != nil {
 		return err
 	}
 	defer object.Close()
-	projection := vam.NewProjection(zctx, object, paths)
+	projection := vam.NewProjection(zed.NewContext(), object, paths)
 	writer, err := c.outputFlags.Open(ctx, local)
 	if err != nil {
 		return err