Step 1 (PR-B): Async project defensive coding cleanup

[jamesfredley]

Step 1 (PR-B) prerequisite for Hibernate 7 work - extracted from the staging branch so it can be reviewed on its own merits.

Context

This change was originally pulled forward into the hibernate7 staging branch as commit e3cad414db on PR #15654. Reviewers (@matrei, @sbglasius) correctly pointed out it is unrelated to the Hibernate 7 clone and should be a standalone PR. Extracting it here against 8.0.x so it can land on its own and then flow naturally into both the staging branch (PR #15654) and Step 2 (PR #15568).

Scope

Nine files in grails-async/ with defensive coding improvements:

1. Null-safety guards

• AbstractPromiseFactory.createPromise(List, List): return an empty PromiseList when closures is null rather than NPE on .size().
• FutureTaskPromise.set(T) and setException(Throwable): null-check successCallbacks and failureCallbacks before synchronizing/iterating.

2. Exception handling

• DelegateAsyncTransformation.getTransformer(): catch Exception (renamed to ignored) instead of Throwable. Catching Throwable swallows Errors that should propagate (OutOfMemoryError, StackOverflowError, etc.) and is widely considered bad style. @sbglasius called this out explicitly in his review of the staging PR.

3. Static analysis hints

• Add @Override annotations on DelegateAsyncTransformation.visit and NoopDelegateAsyncTransactionalMethodTransformer.transformTransactionalMethod.
• Use constant-on-left equality (VOID.equals(name) instead of name.equals(VOID)) to avoid NPE if name is null.
• Change copyParameters(Parameter[]) to varargs copyParameters(Parameter...) for caller convenience.

Why a separate PR

PR #15654 (Step 1) is meant to be a near-pure clone of hibernate5 → hibernate7. PR #15568 (Step 2) is the actual Hibernate 7 logic. Both reviewers asked for cleanup of this nature to be split out so the review effort on Step 1 and Step 2 can stay focused on hibernate-related diffs.

Authorship preserved from the original commit by @jdaugherty.

Related

• Step 1 PR-A: Hibernate 7 - Step 1 #15654 (the hibernate7 clone, already updated to remove logback.groovy and the unrelated stepByStep.adoc change)
• Step 1 PR-C: MongoDatastoreSpec base class + spec refactor (forthcoming)
• Step 1 PR-D: DetachedCriteriaSpec TCK style cleanup (forthcoming)
• Step 2: Hibernate 7 - Step 2 #15568 (the actual Hibernate 7 logic - blocked on Step 1 prerequisites)

[jdaugherty]

These changes were originally authored by walter. I believe they were all issues found by PMD

[Copilot]

Pull request overview

Defensive coding and static-analysis cleanups across grails-async/ as a prerequisite for upcoming Hibernate 7 work, focusing on null-safety, safer exception handling, and minor correctness/clarity improvements.

Changes:

• Add null-safety handling for promise list creation and callback invocation.
• Refine DelegateAsyncTransformation (exception handling scope, @Override, safer equality, varargs signature).
• Minor refactors/cleanups (import ordering, constant immutability, formatting).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
grails-async/plugin/src/main/groovy/org/grails/plugins/web/async/spring/PromiseFactoryBean.groovy	Removes stray trailing whitespace/blank line.
grails-async/plugin/src/main/groovy/org/grails/plugins/web/async/AsyncWebRequestPromiseDecorator.groovy	Import order cleanup.
grails-async/plugin/src/main/groovy/org/grails/async/transform/internal/DefaultDelegateAsyncTransactionalMethodTransformer.groovy	Minor formatting of parameter array constant; import order.
grails-async/plugin/src/main/groovy/grails/async/web/AsyncGrailsWebRequest.groovy	Import ordering cleanup (no functional change).
grails-async/plugin/src/main/groovy/grails/async/services/PersistenceContextPromiseDecorator.groovy	Import order cleanup.
grails-async/gpars/src/main/groovy/org/grails/async/factory/gpars/LoggingPoolFactory.groovy	Makes reflective Method field final (immutable after static init).
grails-async/core/src/main/groovy/org/grails/async/transform/internal/DelegateAsyncTransformation.java	Adds @Override, safer string equality, narrows catch to Exception, changes helper to varargs.
grails-async/core/src/main/groovy/org/grails/async/factory/future/FutureTaskPromise.groovy	Adds null-guards around callback iteration.
grails-async/core/src/main/groovy/grails/async/factory/AbstractPromiseFactory.groovy	Adds null-handling for createPromise(List, List) by returning an “empty” promise result.

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