@@ -8,6 +8,14 @@ NOTE: As semantic versioning states all 0.y.z releases can contain breaking chan
 
 We use *breaking :warning:* to mark changes that are not backward compatible (relates only to v0.y.z releases.)
 
+## [v0.42.3](https://github.com/thanos-io/thanos/tree/release-0.42) - 2026 07 29
+
+Fixes a small bug - like before now Receive on shutdown creates a new block and uploads it.
+
+### Fixed
+
+- [#8948](https://github.com/thanos-io/thanos/pull/8948): receive: Preserve upload on shutdown behaviour
+
 ## [v0.42.2](https://github.com/thanos-io/thanos/tree/release-0.42) - 2026 07 16
 
 Had to do another version release due to broken base image SHAs. No changes.
 
@@ -1,6 +1,6 @@
 # By default we pin to amd64 sha. Use make docker to automatically adjust for arm64 versions.
 ARG BASE_DOCKER_SHA="14d68ca3d69fceaa6224250c83d81d935c053fb13594c811038c461194599973"
-FROM golang:1.26.4-alpine3.20 as builder
+FROM golang:1.26.4-alpine3.24 as builder
 
 WORKDIR $GOPATH/src/github.com/thanos-io/thanos
 # Change in the docker context invalidates the cache so to leverage docker
 
@@ -1 +1 @@
-0.42.2
+0.42.3
@@ -722,8 +722,6 @@ func startTSDBAndUpload(g *run.Group,
 	// TSDBs reload logic, listening on hashring changes.
 	cancel := make(chan struct{})
 	g.Add(func() error {
-		defer close(uploadC)
-
 		// Before quitting, ensure the WAL is flushed and the DBs are closed.
 		defer func() {
 			level.Info(logger).Log("msg", "shutting down storage")
@@ -732,6 +730,11 @@ func startTSDBAndUpload(g *run.Group,
 			} else {
 				level.Info(logger).Log("msg", "storage is flushed successfully")
 			}
+			close(uploadC)
+			// Wait for upload to finish before closing dbs.
+			if upload {
+				<-uploadDone
+			}
 			dbs.Close()
 			level.Info(logger).Log("msg", "storage is closed")
 		}()
@@ -812,6 +815,8 @@ func startTSDBAndUpload(g *run.Group,
 					runutil.CloseWithLogOnErr(logger, bkt, "bucket client")
 				}()
 
+				defer close(uploadDone)
+
 				// Before quitting, ensure all blocks are uploaded.
 				defer func() {
 					<-uploadC // Closed by storage routine when it's done.
@@ -827,8 +832,6 @@ func startTSDBAndUpload(g *run.Group,
 					level.Info(logger).Log("msg", "the final cut block was uploaded", "uploaded", uploaded)
 				}()
 
-				defer close(uploadDone)
-
 				for {
 					select {
 					case <-ctx.Done():
 
@@ -607,6 +607,7 @@ type ReceiveBuilder struct {
 	nativeHistograms      bool
 	labels                []string
 	tenantSplitLabel      string
+	objStoreConfig        *client.BucketConfig
 }
 
 func NewReceiveBuilder(e e2e.Environment, name string) *ReceiveBuilder {
@@ -688,6 +689,11 @@ func (r *ReceiveBuilder) WithNativeHistograms() *ReceiveBuilder {
 	return r
 }
 
+func (r *ReceiveBuilder) WithObjStoreConfig(config client.BucketConfig) *ReceiveBuilder {
+	r.objStoreConfig = &config
+	return r
+}
+
 // Init creates a Thanos Receive instance.
 // If ingestion is enabled it will be configured for ingesting samples.
 // If routing is configured (i.e. hashring configuration is provided) it routes samples to other receivers.
@@ -796,6 +802,14 @@ func (r *ReceiveBuilder) Init() *e2eobs.Observable {
 		args["--tsdb.enable-native-histograms"] = ""
 	}
 
+	if r.objStoreConfig != nil {
+		bktConfigBytes, err := yaml.Marshal(r.objStoreConfig)
+		if err != nil {
+			return &e2eobs.Observable{Runnable: e2e.NewFailedRunnable(r.Name(), errors.Wrapf(err, "generate objstore config: %v", r.objStoreConfig))}
+		}
+		args["--objstore.config"] = string(bktConfigBytes)
+	}
+
 	return e2eobs.AsObservable(r.f.Init(wrapWithDefaults(e2e.StartOptions{
 		Image:     r.image,
 		Command:   e2e.NewCommand("receive", e2e.BuildKingpinArgs(args)...),
 
@@ -34,6 +34,10 @@ import (
 
 	"github.com/efficientgo/core/testutil"
 
+	"github.com/thanos-io/objstore"
+	"github.com/thanos-io/objstore/client"
+	"github.com/thanos-io/objstore/providers/s3"
+
 	"github.com/thanos-io/thanos/pkg/exemplars/exemplarspb"
 	"github.com/thanos-io/thanos/pkg/promclient"
 	"github.com/thanos-io/thanos/pkg/receive"
@@ -1390,3 +1394,59 @@ func TestReceiveWithRelabelConfigSmoke(t *testing.T) {
 		e2emon.WaitMissingMetrics(),
 	))
 }
+
+func TestReceiveUploadOnShutdown(t *testing.T) {
+	t.Parallel()
+
+	e, err := e2e.NewDockerEnvironment("receive-u-s")
+	testutil.Ok(t, err)
+	t.Cleanup(e2ethanos.CleanScenario(t, e))
+
+	const bucket = "receive-upload-shutdown-test"
+	m := e2edb.NewMinio(e, "thanos-minio", bucket, e2edb.WithMinioTLS())
+	testutil.Ok(t, e2e.StartAndWaitReady(m))
+
+	bktConfig := client.BucketConfig{
+		Type:   objstore.S3,
+		Config: e2ethanos.NewS3Config(bucket, m.InternalEndpoint("http"), m.InternalDir()),
+	}
+
+	i := e2ethanos.NewReceiveBuilder(e, "ingestor").
+		WithIngestionEnabled().
+		WithObjStoreConfig(bktConfig).
+		Init()
+	testutil.Ok(t, e2e.StartAndWaitReady(i))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
+	t.Cleanup(cancel)
+
+	require.NoError(t, runutil.RetryWithLog(logkit.NewLogfmtLogger(os.Stdout), 1*time.Second, ctx.Done(), func() error {
+		return storeWriteRequest(ctx, "http://"+i.Endpoint("remote-write")+"/api/v1/receive", &prompb.WriteRequest{
+			Timeseries: []prompb.TimeSeries{
+				{
+					Labels: []prompb.Label{
+						{Name: "__name__", Value: "upload_test_metric"},
+						{Name: "foo", Value: "bar"},
+					},
+					Samples: []prompb.Sample{
+						{Value: 1, Timestamp: time.Now().UnixMilli()},
+					},
+				},
+			},
+		})
+	}))
+
+	testutil.Ok(t, i.Stop())
+
+	l := logkit.NewLogfmtLogger(os.Stdout)
+	bkt, err := s3.NewBucketWithConfig(l,
+		e2ethanos.NewS3Config(bucket, m.Endpoint("http"), m.Dir()), "test-verify", nil)
+	testutil.Ok(t, err)
+
+	var blockCount int
+	testutil.Ok(t, bkt.Iter(ctx, "", func(_ string) error {
+		blockCount++
+		return nil
+	}))
+	require.Greater(t, blockCount, 0, "expected at least one block uploaded to object storage after receiver shutdown")
+}