Avoid race condition in GC_Example test (#10665)

Re-enables https://github.com/enso-org/enso/pull/10602/files#r1690919173 - uses `IO.println` to allow us to see what the CI actually does.

build/build/src/engine/context.rs

@@ -661,12 +661,10 @@ pub async fn runner_sanity_test(
             .args(["--run", repo_root.test.join("Base_Tests").as_str()])
             .set_env_opt(ENSO_JAVA, enso_java)?
             .set_env(ENSO_DATA_DIRECTORY, engine_package)?
-            .run_stdout()
-            .await?;
-        ensure!(
-            test_base.contains("0 tests failed."),
-            "All tests shall succeed. Output:\n{test_base}",
-        );
+            .run_ok()
+            .await;
+        test_base
+    } else {
+        Ok(())
     }
-    Ok(())
 }

engine/runtime/src/main/java/org/enso/interpreter/runtime/ResourceManager.java

@@ -177,29 +177,34 @@ private final class ProcessItems extends ThreadLocalAction implements Runnable {
      */
     @Override
     protected void perform(ThreadLocalAction.Access access) {
+      var isMyThreadChoosen = false;
       for (; ; ) {
         Item[] toProcess;
         synchronized (pendingItems) {
-          request.cancel(false);
+          if (!isMyThreadChoosen) {
+            if (request == null || request.isCancelled()) {
+              // some thread is already handing the request
+              return;
+            } else {
+              // I am choosen and I will loop and process pendingItems
+              // until they are available
+              isMyThreadChoosen = true;
+              // signal others this request has choosen thread
+              request.cancel(false);
+            }
+          }
           if (pendingItems.isEmpty()) {
-            // nothing to process,
-            // signal request is finished
+            // nothing to process anymore,
+            // signal request is finished and new one shall be scheduled
             request = null;
             return;
           }
           toProcess = pendingItems.toArray(Item[]::new);
-          // mark as being processed
-          pendingItems.set(0, null);
+          pendingItems.clear();
         }
-        try {
-          for (var it : toProcess) {
-            it.finalizeNow(context);
-            removeFromItems(it);
-          }
-        } finally {
-          synchronized (pendingItems) {
-            pendingItems.subList(0, toProcess.length).clear();
-          }
+        for (var it : toProcess) {
+          it.finalizeNow(context);
+          removeFromItems(it);
         }
       }
     }

test/Base_Tests/src/Runtime/GC_Example.enso

@@ -1,4 +1,5 @@
 from Standard.Base import all
+import Standard.Base.Errors.Illegal_State.Illegal_State
 import Standard.Base.Runtime.Managed_Resource.Managed_Resource
 import Standard.Base.Runtime.Ref.Ref
 
@@ -15,27 +16,42 @@ type My_Resource
 
 close_resource resource = resource.close
 
-repeat_cleanup_until_done counter =
-    go i =
-        if counter.get == 0 then Nothing else
-            if i % 100 == 0 then
-                IO.println "Still "+counter.get.to_text+" resources to clean up..."
-            Runtime.gc
-            @Tail_Call go i+1
-    go 1
+repeat_cleanup_until_done counter println =
+    deadline = Date_Time.now + (Duration.new minutes=5)
+    while_counter_not_zero i = if counter.get != 0 then
+        if i % 10 == 0 then
+            println "Still "+counter.get.to_text+" resources to clean up..."
 
-perform_test n:Integer println =
+        Runtime.gc
+
+        deadline_not_reached at = if at < deadline then True else
+            message = "Timeout has been reached, but there are "+counter.get.to_text+" resources remaining that were not cleaned up."
+            println message
+            False
+
+        if deadline_not_reached Date_Time.now then
+            @Tail_Call while_counter_not_zero i+1
+
+    while_counter_not_zero 1
 
+perform_test n:Integer println =
+    resource_holder = Ref.new Nothing
     counter = Ref.new 0
-    println "Allocating "+n.to_text+" resources..."
-    0.up_to n . each _->
-        My_Resource.allocate counter
 
-    println "Cleaning up..."
-    repeat_cleanup_until_done counter
-    println "All cleaned up! Remaining: "+counter.get.to_text
+    println "Allocating "+n.to_text+" resources..."
+    allocate_resources ref =
+        all = 0.up_to n . map _->
+            My_Resource.allocate counter
+        ref.put all
+    allocate_resources resource_holder
+
+    println "Cleaning up "+resource_holder.get.length.to_text+" resources"
+    # We replace the vector with Nothing to make the resources inaccessible and schedule them for GC
+    resource_holder.put Nothing
+
+    repeat_cleanup_until_done counter println
+    println "Cleaning finished! Remaining: "+counter.get.to_text
     counter.get
 
 main n=1000000 =
     perform_test n IO.println
-

test/Base_Tests/src/Runtime/Managed_Resource_Spec.enso

@@ -58,9 +58,15 @@ add_specs suite_builder = suite_builder.group "Managed_Resource" group_builder->
         r_3 = Panic.recover Any <| Managed_Resource.bracket 42 (_-> Nothing) (_-> Panic.throw "action")
         r_3.catch . should_equal "action"
 
-    group_builder.specify "allocate lots of resources at once" pending=(if Environment.get "CI" . is_nothing . not then "GC Example is marked as pending as it was causing problems on the CI.") <|
-        remaining = GC_Example.perform_test 100000 (_->Nothing)
-        remaining . should_equal 0
+    group_builder.specify "allocate lots of resources at once" <|
+        messages = Vector.build builder->
+            builder.append '\n'
+            remaining = GC_Example.perform_test 100000 builder.append
+            if remaining == 0 then
+                builder.append "OK"
+
+        if messages.last != "OK" then
+            Test.fail (messages.join '\n')
 
 main filter=Nothing =
     suite = Test.build suite_builder->