Verify `EnsoContext` can be GCed after cleaning up `ContextUtils` rule #14219

JaroslavTulach · 2025-10-29T09:56:34Z

Pull Request Description

Adding support for "assert GC mode" into ContextUtils. The assertGC is invoked after each @Rule or @ClassRuleusage of ContextUtils is being closed. This default behavior can be manually configured via ContextUtils.Builder.assertGC(boolean).

This work is based on investigation of a non-deterministic CI failure. By watching the process performing runtime-integration-tests/test execution in VisualVM at least one memory leak was revealed: That problem was fixed by replacing static final field by EnsoContext.Extra per context value in d21d2fd. That way those cached EnsoMultiTypes shall garbage collect at the same time as EnsoContext.

Important Notes

Originally there seemed to be 173 of instances of org.graalvm.polyglot.Context during test execution. There seemed to be millions of instances of TreeMap$Entry held in the memory:

and they seem to leak via EnsoMultiType.ALL_TYPES:

After this PR this debris will be completely gone!

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

All code follows the
Scala,
Java,
Unit tests have been written where possible.

…tGCTest

…ils usage

JaroslavTulach · 2025-10-29T15:17:02Z

lib/java/test-utils/src/main/java/org/enso/test/utils/ContextUtils.java

+      var ref = new WeakReference<>(ensoContext());
      context.close();
      context = null;
+      assertGC("EnsoContext can be GCed when context is closed", true, ref);


The ultimate goal is to make sure that once org.graalvm.polyglot.Context is closed

all references to EnsoContext are closed

that's not really the case right now and fixes may be needed all over the place to make that happen

JaroslavTulach · 2025-10-30T04:30:14Z

The CI is failing in JVM unit tests (as expected) with a ton of error messages:

There are memory leaks holding EnsoContext in memory somewhere in the core engine code. Next step is to run one of these failing tests, generate heap dump and find out why the context is still held in the memory.

JaroslavTulach · 2025-10-30T05:21:10Z

build.sbt

-        "-Dpolyglot.engine.AllowExperimentalOptions=true"
+        "-Dpolyglot.engine.AllowExperimentalOptions=true",
+        "-XX:+HeapDumpOnOutOfMemoryError",
+        "-XX:HeapDumpPath=" + (Compile / packageBin / artifactPath).value


Update on Nov 6, 2025

with Add Upload heapdump step to all JVM tests jobs #14251 you can download the .hprof file from GitHub Actions CI

How to Analyze Heap Dump

When a test fails because of assertGC, then following message is printed:

java.lang.OutOfMemoryError: Java heap space Dumping heap to /home/devel/NetBeansProjects/enso/enso/engine/runtime-integration-tests/target/scala-2.13/runtime-integration-tests.jar ... Heap dump file created [16382020915 bytes in 18,771 secs] java.lang.OutOfMemoryError: Java heap space | => rat org.enso.test.utils.MemoryUtils.checkAndAlloc(MemoryUtils.java:60) at org.enso.test.utils.MemoryUtils.assertGC(MemoryUtils.java:17) at org.enso.test.utils.ContextUtils.close(ContextUtils.java:134) at org.enso.test.utils.ContextUtils$CustomStatement.evaluate(ContextUtils.java:481) at org.junit.rules.RunRules.evaluate(RunRules.java:20) at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)

with that .hprof file at hand, one can open it in VisualVM as

jvisualvm --openfile ./engine/runtime-integration-tests/java_pid969397.hprof

and then

The problem in previous picture shows a reference from CleanableReference.QUEUE - that may go away eventually, but df08637 does its best to force the processing of the QUEUE.

JaroslavTulach · 2025-10-30T09:18:13Z

With recent changes, there is now 130 failing tests:

   Failed tests:
  	org.enso.interpreter.test.imports.ImportSymbolsTest
  	org.enso.interpreter.test.exports.ExportResolutionOrderingTest
  	org.enso.interpreter.test.meta.MetaIsATest
  	org.enso.compiler.test.ExportCycleDetectionTest
  	org.enso.interpreter.test.privateaccess.PrivateConstructorAccessTest
  	org.enso.interpreter.test.interop.GuestJavaInteropTest
  	org.enso.compiler.test.TypeInferenceTest
  	org.enso.interpreter.test.meta.MetaTypeMethodsTest
  	org.enso.interpreter.test.LazyAtomFieldTest
  	org.enso.compiler.dump.test.DocsGenerateTest
  	org.enso.interpreter.test.ListTest
  	org.enso.interpreter.test.ExtensionMethodResolutionTest
  	org.enso.interpreter.test.privateaccess.PrivateMethodAccessTest
  	org.enso.interpreter.test.interop.TypesExposeConstructorsTest
  	org.enso.interpreter.test.EnsoMultiValueTest
  	org.enso.interpreter.test.VectorSortTest
  	org.enso.interpreter.test.WarningsTest
  	org.enso.interpreter.runtime.ManagedResourceTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeOfNodeTest
  	org.enso.interpreter.caches.HelloWorldCacheTest
  	org.enso.compiler.dump.test.DocsGenerateOrderTest
  	org.enso.interpreter.test.exports.ExportConstructorTest
  	org.enso.interpreter.test.BigNumberTest
  	org.enso.interpreter.test.exports.ExportStaticMethodTest
  	org.enso.interpreter.test.interop.InvokeMemberConsistencyTest
  	org.enso.interpreter.test.builtins.BuiltinTypesExposeMethodsTest
  	org.enso.interpreter.runtime.ResourceManagerTest
  	org.enso.interpreter.test.AtomConstructorTest
  	org.enso.interpreter.test.EnsoMultiValueInteropTest
  	org.enso.interpreter.test.FindExceptionMessageTest
  	org.enso.interpreter.runtime.progress.ProgressTest
  	org.enso.interpreter.test.VectorBuilderTest
  	org.enso.interpreter.test.BinaryOpIntegerTest
  	org.enso.interpreter.test.BinaryDispatchTest
  	org.enso.interpreter.test.privateaccess.PrivateCheckDisabledTest
  	org.enso.interpreter.test.exports.ExportExtensionMethodTest
  	org.enso.compiler.test.BindingsMapResolutionTest
  	org.enso.interpreter.test.interop.MethodInvocationOnTypeConsistencyTest
  	org.enso.interpreter.test.VectorTest
  	org.enso.compiler.test.ExportedSymbolsTest
  	org.enso.interpreter.test.meta.QualifiedNameTest
  	org.enso.interpreter.test.exports.ExportModuleTest
  	org.enso.compiler.test.passes.MethodCallsTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeChainTest
  	org.enso.interpreter.test.exports.ExportConversionMethodTest
  	org.enso.interpreter.test.interop.MetaObjectTest
  	org.enso.compiler.test.passes.resolve.NameResolutionTest
  	org.enso.interpreter.test.scope.ModuleScopeTest
  	org.enso.interpreter.test.BinaryOpFloatTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeOfNodeMultiValueTest
  	org.enso.interpreter.test.meta.EnsoProjectTest
  	org.enso.interpreter.test.instrument.InsightForEnsoTest
  Error during tests:
    org.enso.compiler.test.semantic.ImportExportTest

Fix or make the assertGC check of EnsoContext an opt-in or allow an opt-out?

JaroslavTulach · 2025-10-31T03:45:38Z

There is 55 unit test failures on Windows remaining:

  Failed: Total 27291, Failed 55, Errors 0, Passed 27234, Skipped 2, Ignored 32, Canceled 1, Pending 34
  Failed tests:
  	org.enso.interpreter.test.interop.GuestJavaInteropTest
  	org.enso.interpreter.test.interop.MetaObjectPolyglotTest
  	org.enso.interpreter.test.meta.MetaTypeMethodsTest
  	org.enso.interpreter.test.hash.HashCodeTest
  	org.enso.interpreter.test.EqualsTest
  	org.enso.interpreter.test.VectorSortTest
  	org.enso.interpreter.test.WarningsTest
  	org.enso.interpreter.caches.HelloWorldCacheTest
  	org.enso.interpreter.test.exports.ExportConstructorTest
  	org.enso.interpreter.test.exports.ExportStaticMethodTest
  	org.enso.interpreter.test.interop.InvokeMemberConsistencyTest
  	org.enso.interpreter.test.builtins.BuiltinTypesExposeMethodsTest
  	org.enso.interpreter.test.EnsoMultiValueInteropTest
  	org.enso.interpreter.test.VectorBuilderTest
  	org.enso.interpreter.test.BinaryDispatchTest
  	org.enso.interpreter.test.exports.ExportExtensionMethodTest
  	org.enso.compiler.test.BindingsMapResolutionTest
  	org.enso.interpreter.test.interop.MethodInvocationOnTypeConsistencyTest
  	org.enso.interpreter.test.exports.ExportModuleTest
  	org.enso.compiler.test.passes.MethodCallsTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeChainTest
  	org.enso.interpreter.test.exports.ExportConversionMethodTest
  	org.enso.interpreter.test.interop.MetaObjectTest
  	org.enso.compiler.test.passes.resolve.NameResolutionTest
  	org.enso.interpreter.test.scope.ModuleScopeTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeOfNodeMultiValueTest
  	org.enso.interpreter.test.meta.EnsoProjectTest

Some of these failures will hopefully go away after fc3401b that disables the assertGC check when ContextUtils are used "manually" (e.g. not as a JUnit @Rule).

There are failures in runtime-benchmarks - they should be solved with the new default introduced in fc3401b.

enso-bot · 2025-10-31T04:24:45Z

Jaroslav Tulach reports a new STANDUP for yesterday (2025-10-30):

Progress: .

GC test checks: Verify EnsoContext can be GCed after cleaning up ContextUtils rule #14219 (comment)
onwards to Standard.Google in dual mode: 0b03794
- blocked by a problem:
- multiple JVM per process error -5: 7e69793#r2477114949
reviewing Drata documents: https://discord.com/channels/@me/960509000154247198/1433484775737397309
PR review: Package engine bundle #14223 (review) It should be finished by 2025-11-04.

Discord
Discord - Group Chat That’s All Fun & Games
Discord is great for playing games and chilling with friends, or even building a worldwide community. Customize your own space to talk, play, and hang out.

JaroslavTulach · 2025-10-31T05:21:04Z

Down to seventeen failures:

Failed: Total 27298, Failed 17, Errors 0, Passed 27281, Ignored 32, Pending 30
Failed tests:
  	org.enso.interpreter.test.interop.GuestJavaInteropTest
  	org.enso.interpreter.test.interop.MetaObjectPolyglotTest
  	org.enso.interpreter.test.meta.MetaTypeMethodsTest
  	org.enso.interpreter.test.hash.HashCodeTest
  	org.enso.interpreter.test.EqualsTest
  	org.enso.interpreter.test.VectorSortTest
  	org.enso.interpreter.test.WarningsTest
  	org.enso.interpreter.caches.HelloWorldCacheTest
  	org.enso.interpreter.test.interop.InvokeMemberConsistencyTest
  	org.enso.interpreter.test.builtins.BuiltinTypesExposeMethodsTest
  	org.enso.interpreter.test.EnsoMultiValueInteropTest
  	org.enso.interpreter.test.VectorBuilderTest
  	org.enso.interpreter.test.BinaryDispatchTest
  	org.enso.interpreter.test.interop.MethodInvocationOnTypeConsistencyTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeChainTest
  	org.enso.interpreter.test.interop.MetaObjectTest
  	org.enso.interpreter.node.expression.builtin.meta.TypeOfNodeMultiValueTest

…ng unless special magic is performed

JaroslavTulach · 2025-10-31T13:35:23Z

there is the last remaining failure:
org.enso.interpreter.test.interop.GuestJavaInteropTest
and this time I think it is a real memory leak
maybe just a temporary one, but real

JaroslavTulach · 2025-10-31T15:27:27Z

I believe all tests are fixed. They run in seven minutes:

[info] ScalaTest
[info] Run completed in 6 minutes, 54 seconds.
[info] Total number of tests run: 1372
[info] Suites: completed 101, aborted 0
[info] Tests: succeeded 1372, failed 0, canceled 0, ignored 3, pending 30
[info] All tests passed.
[info] Passed: Total 27282, Failed 0, Errors 0, Passed 27282, Ignored 32, Pending 30
[success] Total time: 415 s (06:55), completed 31. 10. 2025 16:22:42

The memory usage when running `runtime-integration-tests/test` seems to _not leak_ anything. After each test it returns back to previous memory state. The TruffleTCK tests require enormous amount of heap. Not sure why, but then they clean after itself, so the purpose of this PR should be met.

Reviewers, @Akirathan, @hubertp, @4e6 please act!

Akirathan

The amount of explicit null assignment to local variables is surprising. I understand why that is necessary for static fields, but for local variables used inside try-with-resources block?

engine/runtime-compiler/src/main/scala/org/enso/compiler/pass/resolve/TypeSignatures.scala

...runtime-integration-tests/src/test/java/org/enso/compiler/test/ExportCycleDetectionTest.java

… null assignments.

enso-bot · 2025-10-31T17:31:36Z

Jaroslav Tulach reports a new STANDUP for today (2025-10-31):

Progress: .

done with assertGC: Verify EnsoContext can be GCed after cleaning up ContextUtils rule #14219
QA of Enso: https://discord.com/channels/@me/949240296271642634/1433684868205641791
meeting Sylwia & James It should be finished by 2025-11-04.

Discord
Discord - Group Chat That’s All Fun & Games
Discord is great for playing games and chilling with friends, or even building a worldwide community. Customize your own space to talk, play, and hang out.

enso-bot · 2025-11-02T09:09:06Z

Jaroslav Tulach reports a new STANDUP for yesterday (2025-11-01):

Progress: .

fix GC tests: 1b2cef2
fixing TypeInferenceTest.staticCallWithWrongType: Remove duplicated IR ASTs for static methods #13962 (comment)
Complying with Drata It should be finished by 2025-11-04.

enso-bot · 2025-11-03T02:47:36Z

Jaroslav Tulach reports a new STANDUP for yesterday (2025-11-02):

Progress: .

regenerated APIs: 9273b22
compile ydoc-server as a library: Support for dynamic loading of native JVMs #14232 It should be finished by 2025-11-04.

JaroslavTulach · 2025-11-05T16:16:34Z

build.sbt

-        "-Dpolyglot.engine.AllowExperimentalOptions=true"
+        "-Dpolyglot.engine.AllowExperimentalOptions=true",
+        "-XX:+HeapDumpOnOutOfMemoryError",
+        "-XX:HeapDumpPath=" + (Compile / packageBin).value.getParentFile


Now there should be .hprof file in the engine/runtime-integration-tests/target directory when any of the tests yields OutOfMemoryException.

Verify context can be GCed after evaluation

6738185

JaroslavTulach self-assigned this Oct 29, 2025

JaroslavTulach requested review from 4e6 and hubertp as code owners October 29, 2025 09:56

JaroslavTulach added the CI: No changelog needed Do not require a changelog entry for this PR. label Oct 29, 2025

JaroslavTulach requested a review from Akirathan as a code owner October 29, 2025 09:56

JaroslavTulach added 3 commits October 29, 2025 14:12

Cache EnsoMultiType instances per EnsoContext only

d21d2fd

Merge remote-tracking branch 'origin/develop' into wip/jtulach/Contex…

b9f1a97

…tGCTest

Let's make sure EnsoContext is garbage collected after each ContextUt…

f2f638d

…ils usage

JaroslavTulach commented Oct 29, 2025

View reviewed changes

JaroslavTulach changed the title ~~Verify context can be GCed after evaluation~~ Verify EnsoContext can be GCed after cleaning up ContextUtils rule Oct 29, 2025

JaroslavTulach added 3 commits October 30, 2025 06:02

Separating the assertGC into own file

c98bfc3

Avoid stack frame reference to ensoContext to allow GC of EnsoContext

11f1a28

Dump .hprof file on out of memory errors

7a1a95d

JaroslavTulach commented Oct 30, 2025

View reviewed changes

JaroslavTulach added 3 commits October 30, 2025 06:33

Specify path to runtime-integration-tests/target/scala-2.13 directory

d8b80fe

Try harder to process CleanableReference.QUEUE by creating new Context

df08637

Eventually give up on GCing

0cc51c3

JaroslavTulach added 5 commits October 30, 2025 12:03

Don't hold EnsoContext via polyCtx

1a63754

Allow to opt-out of assertGC check for ContextUtils

aa91c51

Introducing topScope() getter for simple access to TopScope

09277b0

More tests that GC EnsoContext

7f4b17d

Clean up local variables to allow GC of the EnsoContext

35014cb

JaroslavTulach added 2 commits October 31, 2025 05:10

assertGC is on by default when used as @rule only

fc3401b

Try harder to GC after five unsuccessful System.gc() calls

be9a9bd

JaroslavTulach added this to Issues Board Oct 31, 2025

JaroslavTulach added the -compiler label Oct 31, 2025

JaroslavTulach moved this from 🌟 Q/A review to 👁️ Code review in Issues Board Oct 31, 2025

JaroslavTulach added 7 commits October 31, 2025 06:56

Clean Parameters when the test suite is over

1addaa1

Clean static state

e4a4ff2

Cleanup static values @afterclass

23dcbef

Cleanup EnsoMultiValues when no longer used

d09e293

Explicitly enter/leave context when computing @Parameterized.Parameters

bff788a

Don't try to access context to assert GC in HelloWorldCacheTest

235a5fb

Disable assertGC in these @Parametrized tests as parameters are leaki…

56c1653

…ng unless special magic is performed

Clean all OtherJvmPool data when closing a channel

e700394

Akirathan approved these changes Oct 31, 2025

View reviewed changes

github-project-automation bot moved this from 👁️ Code review to 🌟 Q/A review in Issues Board Oct 31, 2025

JaroslavTulach added 4 commits October 31, 2025 17:42

Manually used ContextUtils don't check assertGC anymore. Removing the…

daeb088

… null assignments.

= null no longer needed

25314c5

Making anyIr per ModuleContext constant again

31c4c39

Even less = null assignments as assertGC is off for these cases now

153dd0d

assertGC(false) in jvm-interop tests

1b2cef2

JaroslavTulach added the CI: Ready to merge This PR is eligible for automatic merge label Nov 1, 2025

mergify bot merged commit a92e98b into develop Nov 3, 2025
143 of 156 checks passed

mergify bot deleted the wip/jtulach/ContextGCTest branch November 3, 2025 12:39

github-project-automation bot moved this from 🌟 Q/A review to 🟢 Accepted in Issues Board Nov 3, 2025

JaroslavTulach mentioned this pull request Nov 4, 2025

TCK Truffle tests are leaking memory #10805

Closed

JaroslavTulach commented Nov 5, 2025

View reviewed changes

Akirathan mentioned this pull request Nov 5, 2025

Add Upload heapdump step to all JVM tests jobs #14251

Merged

5 tasks

Verify EnsoContext can be GCed after cleaning up ContextUtils rule #14219

Verify EnsoContext can be GCed after cleaning up ContextUtils rule #14219

Uh oh!

Conversation

JaroslavTulach commented Oct 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Pull Request Description

Important Notes

Checklist

Uh oh!

JaroslavTulach Oct 29, 2025

Choose a reason for hiding this comment

Uh oh!

JaroslavTulach commented Oct 30, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

JaroslavTulach Oct 30, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Update on Nov 6, 2025

How to Analyze Heap Dump

Uh oh!

JaroslavTulach Oct 30, 2025

Choose a reason for hiding this comment

Uh oh!

JaroslavTulach commented Oct 30, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

JaroslavTulach commented Oct 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

enso-bot bot commented Oct 31, 2025 • edited by unfurl-links bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

JaroslavTulach commented Oct 31, 2025

Uh oh!

JaroslavTulach commented Oct 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

JaroslavTulach commented Oct 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Akirathan left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

enso-bot bot commented Oct 31, 2025 • edited by unfurl-links bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

enso-bot bot commented Nov 2, 2025

Uh oh!

enso-bot bot commented Nov 3, 2025

Uh oh!

Uh oh!

JaroslavTulach Nov 5, 2025

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Verify `EnsoContext` can be GCed after cleaning up `ContextUtils` rule #14219

Verify `EnsoContext` can be GCed after cleaning up `ContextUtils` rule #14219

JaroslavTulach commented Oct 29, 2025 •

edited

Loading

JaroslavTulach commented Oct 30, 2025 •

edited

Loading

JaroslavTulach Oct 30, 2025 •

edited

Loading

JaroslavTulach commented Oct 30, 2025 •

edited

Loading

JaroslavTulach commented Oct 31, 2025 •

edited

Loading

enso-bot bot commented Oct 31, 2025 •

edited by unfurl-links bot

Loading

JaroslavTulach commented Oct 31, 2025 •

edited

Loading

JaroslavTulach commented Oct 31, 2025 •

edited

Loading

enso-bot bot commented Oct 31, 2025 •

edited by unfurl-links bot

Loading