Changes to support Micronaut processors as a Native Image by graemerocher · Pull Request #12449 · micronaut-projects/micronaut-core

graemerocher · 2026-03-09T09:54:45Z

Summary

Split out non-micronautc prerequisite changes from micronautc: custom javac native image build with annotation processors embedded #12444 so they can be reviewed and merged independently
Keep processor service-loading and visitor bootstrapping updates needed for native-image processor execution
Preserve MethodHandle-first constructor loading in SoftServiceLoader with reflection fallback and coverage in SoftServiceLoaderTest

Verification

./gradlew :micronaut-core:test --tests 'io.micronaut.core.io.service.SoftServiceLoaderTest' :micronaut-core-processor:compileJava :micronaut-inject-java:compileJava

Copilot

Pull request overview

This PR updates Micronaut’s annotation processing/visitor service loading to better support execution in native-image contexts (e.g., by using an alternative classloader strategy and a ServiceLoader fallback), and enhances SoftServiceLoader instantiation behavior with a MethodHandle-first approach and reflection fallback.

Changes:

Add optional context-classloader-based service loading (behind micronaut.processing.use.context.classloader) and JDK ServiceLoader fallbacks for visitors/mappers/transformers.
Make SoftServiceLoader instantiate services via MethodHandles first, with reflection fallback when access via MethodHandles is not possible.
Add a regression test covering reflection fallback when MethodHandles cannot access a constructor.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
inject-java/src/main/java/io/micronaut/annotation/processing/TypeElementVisitorProcessor.java	Adds context classloader selection and a ServiceLoader fallback for `TypeElementVisitor` discovery; adjusts supported-options detection and deduping.
core/src/main/java/io/micronaut/core/io/service/SoftServiceLoader.java	Introduces shared instantiation helper using MethodHandles first with reflection fallback.
core/src/test/java/io/micronaut/core/io/service/SoftServiceLoaderTest.java	Adds test ensuring reflection fallback is used when MethodHandles cannot access a constructor.
core-processor/src/main/java/io/micronaut/inject/visitor/BeanElementVisitorLoader.java	Adds context classloader selection and ServiceLoader fallback for `BeanElementVisitor` loading.
core-processor/src/main/java/io/micronaut/inject/annotation/AbstractAnnotationMetadataBuilder.java	Switches mapper/transformer/remapper/validator loading to use context classloader selection and ServiceLoader fallback.

graemerocher · 2026-03-09T10:15:43Z

@copilot create a PR that targets this PR and addresses you comments

Copilot · 2026-03-09T10:15:50Z

@graemerocher I've opened a new pull request, #12451, to work on those changes. Once the pull request is ready, I'll request review from you.

…zy first-service loading, handle InaccessibleObjectException in reflection fallback, preserve order in visitor dedup (#12451) * Initial plan * Address PR review comments: centralize property constant, lazy first-service load, InaccessibleObjectException handling, LinkedHashMap for dedup Co-authored-by: graemerocher <66626+graemerocher@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: graemerocher <66626+graemerocher@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

graemerocher · 2026-03-09T11:47:31Z

@copilot create a new PR addressing the comments

Copilot · 2026-03-09T11:47:40Z

@graemerocher I've opened a new pull request, #12453, to work on those changes. Once the pull request is ready, I'll request review from you.

… transparency in service loading (#12453) * Address review feedback: iterator-based ServiceLoader fallbacks, preserve exception cause, update StaticDefinition Javadoc Co-authored-by: graemerocher <66626+graemerocher@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: graemerocher <66626+graemerocher@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Copilot · 2026-03-09T13:42:49Z

+        def previous = Thread.currentThread().contextClassLoader
+        def propertyName = "micronaut.processing.use.context.classloader"
+        def previousProperty = System.getProperty(propertyName)
+


This test hard-codes the system property name ("micronaut.processing.use.context.classloader") even though the code introduces VisitorContext.MICRONAUT_PROCESSING_USE_CONTEXT_CLASSLOADER. Using the constant here would prevent drift if the option key changes in the future.

Copilot · 2026-03-09T13:42:50Z

+        for (ServiceDefinition<S> definition : SoftServiceLoader.load(serviceType, classLoader).disableFork()) {
+            try {
+                if (definition.isPresent()) {
+                    return Optional.of(definition.load());
+                }
+            } catch (Throwable e) {
+                if (e instanceof VirtualMachineError virtualMachineError) {
+                    throw virtualMachineError;
+                }
+            }
+        }
+        Iterator<ServiceLoader.Provider<S>> it = ServiceLoader.load(serviceType, classLoader).stream().iterator();
+        while (it.hasNext()) {
+            try {
+                return Optional.of(it.next().get());
+            } catch (Throwable e) {
+                if (e instanceof VirtualMachineError virtualMachineError) {
+                    throw virtualMachineError;
+                }
+            }
+        }


loadFirstService catches and ignores any throwable from ServiceDefinition#load() / provider creation (except VirtualMachineError). Previously, a failing first AnnotatedElementValidator would surface immediately; now it can be silently skipped, potentially disabling validation with no signal. Consider only ignoring known “soft” failures (e.g. missing classes) and otherwise rethrowing or at least recording/reporting the error.

Copilot · 2026-03-09T13:42:50Z

+        Iterator<ServiceLoader.Provider<BeanElementVisitor>> iterator = ServiceLoader.load(BeanElementVisitor.class, classLoader).stream().iterator();
+        while (iterator.hasNext()) {
+            try {
+                BeanElementVisitor<?> visitor = iterator.next().get();
+                if (visitor.isEnabled()) {
+                    visitors.add(visitor);
+                }
+            } catch (Throwable e) {
+                if (e instanceof VirtualMachineError virtualMachineError) {
+                    throw virtualMachineError;
+                }
+            }


The ServiceLoader fallback loop swallows all throwables (except VirtualMachineError). If a BeanElementVisitor is present but misconfigured (e.g. ServiceConfigurationError) this will be silently ignored and visitor execution may be partially/entirely disabled without any indication. Consider rethrowing ServiceConfigurationError/LinkageError (or otherwise surfacing the failure) to avoid masking real configuration issues.

sonarqubecloud · 2026-03-09T14:32:28Z

Quality Gate failed

Failed conditions
53.1% Coverage on New Code (required ≥ 70%)

See analysis details on SonarQube Cloud

Changes to support Micronaut processors as a Native Image

c014493

Copilot AI review requested due to automatic review settings March 9, 2026 09:54

Copilot started reviewing on behalf of graemerocher March 9, 2026 09:55 View session

graemerocher mentioned this pull request Mar 9, 2026

micronautc: custom javac native image build with annotation processors embedded #12450

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Copilot AI reviewed Mar 9, 2026

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Copilot AI mentioned this pull request Mar 9, 2026

Address review feedback: centralize classloader property constant, lazy first-service loading, handle InaccessibleObjectException in reflection fallback, preserve order in visitor dedup #12451

Merged

graemerocher added the type: improvement A minor improvement to an existing feature label Mar 9, 2026

fix checkstyle declaration order in processor classes

c850b67

Copilot AI review requested due to automatic review settings March 9, 2026 11:34

Copilot started reviewing on behalf of graemerocher March 9, 2026 11:41 View session

Copilot AI reviewed Mar 9, 2026

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Copilot AI mentioned this pull request Mar 9, 2026

Fix unsafe ServiceLoader stream materialization and improve exception transparency in service loading #12453

Merged

Copilot AI and others added 2 commits March 9, 2026 14:14

Increase coverage for visitor classloader discovery paths

299a837

Copilot AI review requested due to automatic review settings March 9, 2026 13:32

Copilot started reviewing on behalf of graemerocher March 9, 2026 13:32 View session

graemerocher requested a review from dstepanov March 9, 2026 13:39

sdelamo approved these changes Mar 9, 2026

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Copilot AI reviewed Mar 9, 2026

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include warnings when unable to load type element visitor

b196abb

graemerocher merged commit c0b2f34 into 5.0.x Mar 9, 2026
13 of 14 checks passed

graemerocher deleted the micronautc-processors-native-image-support branch March 9, 2026 14:34

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graemerocher commented Mar 9, 2026

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graemerocher commented Mar 9, 2026

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sonarqubecloud Bot commented Mar 9, 2026

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