Add '--install-finalizer' flag to ServiceResourceProxy.

lib/system/containers.toit

@@ -85,9 +85,10 @@ class Container extends ServiceResourceProxy:
   constructor.internal_ --handle/int --.id --.gid --on-event/Lambda? --on-stopped/Lambda?:
     on-event_ = on-event
     on-stopped_ = on-stopped
-    super _client_ handle
+    super _client_ handle --install-finalizer=(not (on-stopped or on-event))
 
   close -> none:
+    catch --trace: throw "close"
     // Make sure anyone waiting for the result now or in the future
     // knows that we got closed before getting an exit code.
     if not result_.has-value: result_.set null

lib/system/services.toit

@@ -539,8 +539,8 @@ abstract class ServiceResourceProxy:
   client_/ServiceClient ::= ?
   _handle_/int? := ?
 
-  constructor .client_ ._handle_:
-    add-finalizer this:: close
+  constructor .client_ ._handle_ --install-finalizer/bool=true:
+    if install-finalizer: add-finalizer this:: close
     if _handle_ & 1 == 1:
       ServiceResourceProxyManager_.instance.register client_.id _handle_ this
 

tests/containers-test.toit

@@ -4,6 +4,7 @@
 
 import monitor
 import system.containers
+import system
 import expect show *
 
 main arguments:
@@ -17,6 +18,7 @@ main arguments:
   test-images
   test-start
   test-background-state-changed
+  test-finalizer
 
 test-images:
   images/List := containers.images
@@ -61,6 +63,15 @@ test-start:
   expect-equals 0 lambda4-value
   expect-equals 0 sub4.wait
 
+test-finalizer:
+  // A container should receive the stop notification even if we don't have
+  // any pointer to the actual container anymore.
+  latch := monitor.Latch
+  containers.start containers.current {:} --on-stopped=(:: latch.set true)
+  // Force a GC.
+  system.process-stats --gc
+  with-timeout --ms=5_000: latch.get
+
 test-background-state-changed:
   channel := monitor.Channel 1
   sub := containers.start containers.current { "background-state-test": true }