From 3b1004c4d9d5e2d6102dc3134fe7ed83eaabcfa6 Mon Sep 17 00:00:00 2001
From: jarek <jkrochmalski@gmail.com>
Date: Tue, 31 Mar 2026 15:04:46 +0200
Subject: [PATCH] fix: gate extra EndpointsConfig behind API >= 1.44

Before API 1.44 (Docker Engine 25.0), ContainerCreate only accepted a
single EndpointsConfig entry. Passing multiple entries silently drops
all but one network, leaving containers under-connected on older daemons
such as Docker 20.10 or Synology DSM 7.1/7.2.

Add apiVersion144 constant and wrap the secondary-networks loop in
defaultNetworkSettings so that only the primary network is included in
the ContainerCreate call when the negotiated API version is below 1.44.

Signed-off-by: jarek <jkrochmalski@gmail.com>
---
 pkg/compose/api_versions.go | 10 ++++++++++
 pkg/compose/create.go       | 16 ++++++++++------
 pkg/compose/create_test.go  | 24 ++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/pkg/compose/api_versions.go b/pkg/compose/api_versions.go
index bccb4ad27..d39aef8aa 100644
--- a/pkg/compose/api_versions.go
+++ b/pkg/compose/api_versions.go
@@ -19,6 +19,16 @@ package compose
 // Docker Engine API version constants.
 // These versions correspond to specific Docker Engine releases and their features.
 const (
+	// apiVersion144 represents Docker Engine API version 1.44 (Engine v25.0).
+	//
+	// New features in this version:
+	//  - ContainerCreate API accepts multiple EndpointsConfig entries
+	//
+	// Before this version:
+	//  - Only a single EndpointsConfig entry was accepted in ContainerCreate
+	//  - Extra networks must be connected individually after container creation via NetworkConnect
+	apiVersion144 = "1.44"
+
 	// apiVersion148 represents Docker Engine API version 1.48 (Engine v28.0).
 	//
 	// New features in this version:
diff --git a/pkg/compose/create.go b/pkg/compose/create.go
index 78db3d0fd..cc0b4afbc 100644
--- a/pkg/compose/create.go
+++ b/pkg/compose/create.go
@@ -563,13 +563,17 @@ func defaultNetworkSettings(project *types.Project,
 	// so we can pass all the extra networks we want the container to be connected to
 	// in the network configuration instead of connecting the container to each extra
 	// network individually after creation.
-	for _, networkKey := range serviceNetworks {
-		epSettings, err := createEndpointSettings(project, service, serviceIndex, networkKey, links, useNetworkAliases)
-		if err != nil {
-			return "", nil, err
+	// For older API versions, extra networks are connected via NetworkConnect after
+	// container creation (see createMobyContainer in convergence.go).
+	if !versions.LessThan(version, apiVersion144) {
+		for _, networkKey := range serviceNetworks {
+			epSettings, err := createEndpointSettings(project, service, serviceIndex, networkKey, links, useNetworkAliases)
+			if err != nil {
+				return "", nil, err
+			}
+			mobyNetworkName := project.Networks[networkKey].Name
+			endpointsConfig[mobyNetworkName] = epSettings
 		}
-		mobyNetworkName := project.Networks[networkKey].Name
-		endpointsConfig[mobyNetworkName] = epSettings
 	}
 
 	networkConfig := &network.NetworkingConfig{
diff --git a/pkg/compose/create_test.go b/pkg/compose/create_test.go
index 2ac5c392b..e08e4227d 100644
--- a/pkg/compose/create_test.go
+++ b/pkg/compose/create_test.go
@@ -273,6 +273,30 @@ func TestDefaultNetworkSettings(t *testing.T) {
 		assert.Check(t, cmp.Nil(networkConfig))
 	})
 
+	t.Run("returns only primary network in EndpointsConfig for API < 1.44", func(t *testing.T) {
+		service := composetypes.ServiceConfig{
+			Name: "myService",
+			Networks: map[string]*composetypes.ServiceNetworkConfig{
+				"myNetwork1": {Priority: 10},
+				"myNetwork2": {Priority: 1000},
+			},
+		}
+		project := composetypes.Project{
+			Name:     "myProject",
+			Services: composetypes.Services{"myService": service},
+			Networks: composetypes.Networks(map[string]composetypes.NetworkConfig{
+				"myNetwork1": {Name: "myProject_myNetwork1"},
+				"myNetwork2": {Name: "myProject_myNetwork2"},
+			}),
+		}
+
+		networkMode, networkConfig, err := defaultNetworkSettings(&project, service, 1, nil, true, "1.43")
+		assert.NilError(t, err)
+		assert.Equal(t, string(networkMode), "myProject_myNetwork2")
+		assert.Check(t, cmp.Len(networkConfig.EndpointsConfig, 1))
+		assert.Check(t, cmp.Contains(networkConfig.EndpointsConfig, "myProject_myNetwork2"))
+	})
+
 	t.Run("returns defined network mode if explicitly set", func(t *testing.T) {
 		service := composetypes.ServiceConfig{
 			Name:        "myService",