drop extends restrictions

Signed-off-by: Nicolas De Loof <[email protected]>

loader/extends.go

@@ -27,10 +27,6 @@ import (
 	"github.com/compose-spec/compose-go/v2/types"
 )
 
-// as we use another service definition by `extends`, we must exclude attributes which creates dependency to another service
-// see https://github.com/compose-spec/compose-spec/blob/main/05-services.md#restrictions
-var exclusions = []string{"depends_on", "volumes_from"}
-
 func ApplyExtends(ctx context.Context, dict map[string]any, opts *Options, tracker *cycleTracker, post ...PostProcessor) error {
 	a, ok := dict["services"]
 	if !ok {
@@ -123,9 +119,6 @@ func applyServiceExtends(ctx context.Context, name string, services map[string]a
 			},
 		})
 	}
-	for _, exclusion := range exclusions {
-		delete(source, exclusion)
-	}
 	merged, err := override.ExtendService(source, service)
 	if err != nil {
 		return nil, err

loader/extends_test.go

@@ -322,6 +322,7 @@ services:
       file: ./testdata/extends/depends_on.yaml
       service: with_volumes_from
 `,
+			wantErr: `service "bar" depends on undefined service "zot"`,
 		},
 		{
 			name: "depends_on",
@@ -333,6 +334,7 @@ services:
       file: ./testdata/extends/depends_on.yaml
       service: with_depends_on
 `,
+			wantErr: `service "bar" depends on undefined service "zot"`,
 		},
 		{
 			name: "shared ipc",
@@ -397,7 +399,7 @@ services:
   
   service_b:
     extends: service_a
-    depends_on:
+    depends_on: !override
       - service_a
 
   service_c: