service hash MUST exclude replicas

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>

pkg/compose/hash.go

@@ -29,6 +29,10 @@ func ServiceHash(o types.ServiceConfig) (string, error) {
 	o.Build = nil
 	o.PullPolicy = ""
 	o.Scale = 1
+	if o.Deploy != nil {
+		var one uint64 = 1
+		o.Deploy.Replicas = &one
+	}
 	bytes, err := json.Marshal(o)
 	if err != nil {
 		return "", err

pkg/compose/hash_test.go

@@ -0,0 +1,43 @@
+/*
+   Copyright 2020 Docker Compose CLI authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package compose
+
+import (
+	"testing"
+
+	"github.com/compose-spec/compose-go/types"
+	"gotest.tools/v3/assert"
+)
+
+func TestServiceHash(t *testing.T) {
+	hash1, err := ServiceHash(serviceConfig(1))
+	assert.NilError(t, err)
+	hash2, err := ServiceHash(serviceConfig(2))
+	assert.NilError(t, err)
+	assert.Equal(t, hash1, hash2)
+}
+
+func serviceConfig(replicas uint64) types.ServiceConfig {
+	return types.ServiceConfig{
+		Scale: int(replicas),
+		Deploy: &types.DeployConfig{
+			Replicas: &replicas,
+		},
+		Name:  "foo",
+		Image: "bar",
+	}
+}