refactor(general): levarage stdlib's context.WithoutCancel(ctx) (#4159)

Removes `internal/ctxutil` package with equivalent implementation

cli/command_server_start.go

@@ -20,7 +20,6 @@
 	htpasswd "github.com/tg123/go-htpasswd"
 
 	"github.com/kopia/kopia/internal/auth"
-	"github.com/kopia/kopia/internal/ctxutil"
 	"github.com/kopia/kopia/internal/server"
 	"github.com/kopia/kopia/repo"
 )
@@ -256,11 +255,12 @@ func (c *commandServerStart) run(ctx context.Context) (reterr error) {
 	if c.serverStartShutdownWhenStdinClosed {
 		log(ctx).Info("Server will close when stdin is closed...")
 
-		ctxutil.GoDetached(ctx, func(ctx context.Context) {
+		go func() {
+			ctx := context.WithoutCancel(ctx)
 			// consume all stdin and close the server when it closes
 			io.Copy(io.Discard, os.Stdin) //nolint:errcheck
 			shutdownHTTPServer(ctx, httpServer)
-		})
+		}()
 	}
 
 	onExternalConfigReloadRequest(srv.Refresh)

internal/cache/cache_storage.go

@@ -8,7 +8,6 @@
 
 	"github.com/pkg/errors"
 
-	"github.com/kopia/kopia/internal/ctxutil"
 	"github.com/kopia/kopia/internal/ospath"
 	"github.com/kopia/kopia/repo/blob"
 	"github.com/kopia/kopia/repo/blob/filesystem"
@@ -45,7 +44,7 @@ func NewStorageOrNil(ctx context.Context, cacheDir string, maxBytes int64, subdi
 		}
 	}
 
-	fs, err := filesystem.New(ctxutil.Detach(ctx), &filesystem.Options{
+	fs, err := filesystem.New(context.WithoutCancel(ctx), &filesystem.Options{
 		Path: contentCacheDir,
 		Options: sharded.Options{
 			DirectoryShards: []int{2},

internal/ctxutil/detach.go

@@ -1,28 +0,0 @@
-// Package ctxutil implements utilities for manipulating context.
-package ctxutil
-
-import (
-	"context"
-)
-
-type detachedContext struct {
-	// inherit most methods from context.Background()
-	context.Context                 //nolint:containedctx
-	wrapped         context.Context //nolint:containedctx
-}
-
-// Detach returns a context that inheris provided context's values but not deadline or cancellation.
-func Detach(ctx context.Context) context.Context {
-	return detachedContext{context.Background(), ctx}
-}
-
-// GoDetached invokes the provided function in a goroutine where the context is detached.
-func GoDetached(ctx context.Context, fun func(ctx context.Context)) {
-	go func() {
-		fun(Detach(ctx))
-	}()
-}
-
-func (d detachedContext) Value(key interface{}) interface{} {
-	return d.wrapped.Value(key)
-}

internal/scheduler/scheduler.go

@@ -10,7 +10,6 @@
 	"time"
 
 	"github.com/kopia/kopia/internal/clock"
-	"github.com/kopia/kopia/internal/ctxutil"
 	"github.com/kopia/kopia/repo/logging"
 )
 
@@ -66,7 +65,7 @@ func Start(ctx context.Context, getItems GetItemsFunc, opts Options) *Scheduler
 	go func() {
 		defer s.wg.Done()
 
-		s.run(ctxutil.Detach(ctx))
+		s.run(context.WithoutCancel(ctx))
 	}()
 
 	return s

internal/server/server.go

@@ -21,7 +21,6 @@
 
 	"github.com/kopia/kopia/internal/auth"
 	"github.com/kopia/kopia/internal/clock"
-	"github.com/kopia/kopia/internal/ctxutil"
 	"github.com/kopia/kopia/internal/mount"
 	"github.com/kopia/kopia/internal/passwordpersist"
 	"github.com/kopia/kopia/internal/scheduler"
@@ -362,7 +361,7 @@ func (s *Server) handleRequestPossiblyNotConnected(isAuthorized isAuthorizedFunc
 		// process the request while ignoring the cancellation signal
 		// to ensure all goroutines started by it won't be canceled
 		// when the request finishes.
-		ctx = ctxutil.Detach(ctx)
+		ctx = context.WithoutCancel(ctx)
 
 		if isAuthorized(ctx, rc) {
 			v, err = f(ctx, rc)
@@ -585,7 +584,7 @@ func (s *Server) SetRepository(ctx context.Context, rep repo.Repository) error {
 		s.maint = nil
 	}
 
-	s.sched = scheduler.Start(ctxutil.Detach(ctx), s.getSchedulerItems, scheduler.Options{
+	s.sched = scheduler.Start(context.WithoutCancel(ctx), s.getSchedulerItems, scheduler.Options{
 		TimeNow:        clock.Now,
 		Debug:          s.options.DebugScheduler,
 		RefreshChannel: s.schedulerRefresh,

internal/server/source_manager.go

@@ -11,7 +11,6 @@
 	"github.com/kopia/kopia/fs"
 	"github.com/kopia/kopia/fs/localfs"
 	"github.com/kopia/kopia/internal/clock"
-	"github.com/kopia/kopia/internal/ctxutil"
 	"github.com/kopia/kopia/internal/serverapi"
 	"github.com/kopia/kopia/internal/uitask"
 	"github.com/kopia/kopia/repo"
@@ -159,7 +158,7 @@ func (s *sourceManager) start(ctx context.Context, isLocal bool) {
 
 func (s *sourceManager) run(ctx context.Context, isLocal bool) {
 	// make sure we run in a detached context, which ignores outside cancellation and deadline.
-	ctx = ctxutil.Detach(ctx)
+	ctx = context.WithoutCancel(ctx)
 
 	s.setStatus("INITIALIZING")
 	defer s.setStatus("STOPPED")

repo/grpc_repository_client.go

@@ -18,7 +18,6 @@
 	"google.golang.org/grpc/credentials"
 
 	"github.com/kopia/kopia/internal/clock"
-	"github.com/kopia/kopia/internal/ctxutil"
 	"github.com/kopia/kopia/internal/gather"
 	apipb "github.com/kopia/kopia/internal/grpcapi"
 	"github.com/kopia/kopia/internal/retry"
@@ -739,7 +738,7 @@ func (r *grpcRepositoryClient) WriteContent(ctx context.Context, data gather.Byt
 	// clone so that caller can reuse the buffer
 	clone := data.ToByteSlice()
 
-	if err := r.doWriteAsync(ctxutil.Detach(ctx), contentID, clone, prefix, comp); err != nil {
+	if err := r.doWriteAsync(context.WithoutCancel(ctx), contentID, clone, prefix, comp); err != nil {
 		return content.EmptyID, err
 	}
 
@@ -897,7 +896,7 @@ func (r *grpcRepositoryClient) getOrEstablishInnerSession(ctx context.Context) (
 		r.innerSessionAttemptCount++
 
 		v, err := retry.WithExponentialBackoff(ctx, "establishing session", func() (*grpcInnerSession, error) {
-			sess, err := cli.Session(ctxutil.Detach(ctx))
+			sess, err := cli.Session(context.WithoutCancel(ctx))
 			if err != nil {
 				return nil, errors.Wrap(err, "Session()")
 			}