fix: merge deploy.restart_policy fields instead of replacing restart

pkg/compose/create.go

@@ -763,13 +763,11 @@ func getRestartPolicy(service types.ServiceConfig) container.RestartPolicy {
 	}
 	if service.Deploy != nil && service.Deploy.RestartPolicy != nil {
 		policy := *service.Deploy.RestartPolicy
-		var attempts int
-		if policy.MaxAttempts != nil {
-			attempts = int(*policy.MaxAttempts)
+		if policy.Condition != "" {
+			restart.Name = mapRestartPolicyCondition(policy.Condition)
 		}
-		restart = container.RestartPolicy{
-			Name:              mapRestartPolicyCondition(policy.Condition),
-			MaximumRetryCount: attempts,
+		if policy.MaxAttempts != nil {
+			restart.MaximumRetryCount = int(*policy.MaxAttempts)
 		}
 	}
 	return restart

pkg/compose/create_test.go

@@ -544,3 +544,42 @@ func TestSetBlkio(t *testing.T) {
 	assert.Equal(t, resources.BlkioDeviceWriteBps[0].Rate, uint64(3))
 	assert.Assert(t, resources.BlkioDeviceWriteIOps == nil)
 }
+
+func TestGetRestartPolicy(t *testing.T) {
+	maxAttempts := uint64(5)
+	s := composetypes.ServiceConfig{Restart: "unless-stopped"}
+	assert.Equal(t, container.RestartPolicyUnlessStopped, getRestartPolicy(s).Name)
+
+	// deploy.restart_policy overrides the fields it sets
+	s = composetypes.ServiceConfig{
+		Restart: "unless-stopped",
+		Deploy: &composetypes.DeployConfig{
+			RestartPolicy: &composetypes.RestartPolicy{Condition: "on-failure", MaxAttempts: &maxAttempts},
+		},
+	}
+	p := getRestartPolicy(s)
+	assert.Equal(t, container.RestartPolicyOnFailure, p.Name)
+	assert.Equal(t, 5, p.MaximumRetryCount)
+
+	// a deploy.restart_policy without condition (e.g. delay-only) must not
+	// clobber the service-level restart with an empty engine policy name
+	s = composetypes.ServiceConfig{
+		Restart: "on-failure:3",
+		Deploy: &composetypes.DeployConfig{
+			RestartPolicy: &composetypes.RestartPolicy{},
+		},
+	}
+	p = getRestartPolicy(s)
+	assert.Equal(t, container.RestartPolicyOnFailure, p.Name)
+	assert.Equal(t, 3, p.MaximumRetryCount)
+
+	// deploy.restart_policy still applies when there is no service-level restart
+	s = composetypes.ServiceConfig{
+		Deploy: &composetypes.DeployConfig{
+			RestartPolicy: &composetypes.RestartPolicy{Condition: "unless-stopped"},
+		},
+	}
+	p = getRestartPolicy(s)
+	assert.Equal(t, container.RestartPolicyUnlessStopped, p.Name)
+	assert.Equal(t, 0, p.MaximumRetryCount)
+}