1 files changed, 84 insertions, 0 deletions
diff --git a/lib/model/indexhandler_test.go b/lib/model/indexhandler_test.go
new file mode 100644
index 000000000..ba571028d
--- /dev/null
+++ b/lib/model/indexhandler_test.go
@@ -0,0 +1,84 @@
+// Copyright (C) 2024 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package model_test
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/model/mocks"
+	"github.com/syncthing/syncthing/lib/protocol"
+	protomock "github.com/syncthing/syncthing/lib/protocol/mocks"
+	"github.com/syncthing/syncthing/lib/testutil"
+)
+
+func TestIndexhandlerConcurrency(t *testing.T) {
+	// Verify that sending a lot of index update messages using the
+	// FileInfoBatch works and doesn't trigger the race detector.
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+	ci := &protomock.ConnectionInfo{}
+
+	m1 := &mocks.Model{}
+	c1 := protocol.NewConnection(protocol.EmptyDeviceID, ar, bw, testutil.NoopCloser{}, m1, ci, protocol.CompressionNever, nil, nil)
+	c1.Start()
+	defer c1.Close(io.EOF)
+
+	m2 := &mocks.Model{}
+	c2 := protocol.NewConnection(protocol.EmptyDeviceID, br, aw, testutil.NoopCloser{}, m2, ci, protocol.CompressionNever, nil, nil)
+	c2.Start()
+	defer c2.Close(io.EOF)
+
+	c1.ClusterConfig(protocol.ClusterConfig{})
+	c2.ClusterConfig(protocol.ClusterConfig{})
+	c1.Index(ctx, "foo", nil)
+	c2.Index(ctx, "foo", nil)
+
+	const msgs = 5e2
+	const files = 1e3
+
+	recvd := 0
+	m2.IndexUpdateCalls(func(_ protocol.Connection, idxUp *protocol.IndexUpdate) error {
+		for j := 0; j < files; j++ {
+			if n := idxUp.Files[j].Name; n != fmt.Sprintf("f%d-%d", recvd, j) {
+				t.Error("wrong filename", n)
+			}
+		}
+		recvd++
+		return nil
+	})
+
+	b1 := db.NewFileInfoBatch(func(fs []protocol.FileInfo) error {
+		return c1.IndexUpdate(ctx, "foo", fs)
+	})
+	for i := 0; i < msgs; i++ {
+		for j := 0; j < files; j++ {
+			b1.Append(protocol.FileInfo{
+				Name:   fmt.Sprintf("f%d-%d", i, j),
+				Blocks: []protocol.BlockInfo{{Hash: make([]byte, 32)}},
+			})
+		}
+		if err := b1.Flush(); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	c1.Close(io.EOF)
+	c2.Close(io.EOF)
+	<-c1.Closed()
+	<-c2.Closed()
+
+	if recvd != msgs-1 {
+		t.Error("didn't receive all expected messages")
+	}
+}