[jira] [Assigned] (IGNITE-28520) Auto-generate prepareMarshalCacheObjects to replace hand-written CO traversal in GridCacheMessage subclasses

["Anton Vinogradov (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-28520?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Anton Vinogradov reassigned IGNITE-28520:
-----------------------------------------

    Assignee: Anton Vinogradov  (was: Alex Abashev)

> Auto-generate prepareMarshalCacheObjects to replace hand-written CO traversal in GridCacheMessage subclasses
> ------------------------------------------------------------------------------------------------------------
>
>                 Key: IGNITE-28520
>                 URL: https://issues.apache.org/jira/browse/IGNITE-28520
>             Project: Ignite
>          Issue Type: Task
>            Reporter: Alex Abashev
>            Assignee: Anton Vinogradov
>            Priority: Minor
>              Labels: IEP-132, ise
>             Fix For: 2.19
>
>          Time Spent: 4h 40m
>  Remaining Estimate: 0h
>
> h2. Summary
> The CacheObject pre-marshal pass already runs on the user thread — {{GridCacheIoManager.onSend}} has been calling {{msg.prepareMarshal(cctx)}} on the sender thread since 2014 (commit by Anton Irinev, before {{ignite-63}}). This ticket is *not* about moving work off the NIO worker; it is about replacing the per-class hand-written CO traversal with a generated, auto-invoked equivalent.
> Today every {{GridCacheMessage}} subclass that carries {{CacheObject}} fields has a hand-written {{prepareMarshal(GridCacheSharedContext)}} override that walks those fields and calls {{co.prepareMarshal(ctx)}} on each. Adding a new {{@Order CO}} field to such a class requires a matching update of the override. Forgetting that update silently moves that field's {{Marshaller.marshal}} call onto the NIO writer (it runs lazily inside {{writeTo}} when {{valBytes == null}}), which is the regression mode this ticket exists to prevent.
> After this ticket lands, the same traversal is generated by APT and auto-invoked from the framework — so coverage is structural rather than maintained by hand.
> h2. What changes
> * {{MessageSerializer}} interface gets a new {{default void prepareMarshalCacheObjects(M msg, CacheObjectValueContext ctx)}} (no-op default).
> * {{MessageSerializerGenerator}} (APT) emits this method on every concrete serializer with at least one traversable {{@Order}} field; recurses into nested concrete {{Message}} types via per-class {{*_SER}} static fields. Recursion is blocked only for {{GridCacheIdMessage}} subclasses (top-level routable messages) — helper messages with {{@Order int cacheId}} ({{GridCacheReturn}}, {{IgniteTxKey}}, {{IgniteTxEntry}}, {{GridCacheEntryInfo}}, {{UpdateErrors}}) are recursable.
> * {{GridCacheIoManager.onSend}} adds {{prepareMarshalGeneratedCacheObjects(msg)}} after the existing {{msg.prepareMarshal(cctx)}}. Helper is gated on {{msg instanceof GridCacheIdMessage}} and resolves {{cacheObjectContext}} from {{((GridCacheIdMessage)msg).cacheId()}}. Both calls run on the user thread, both are idempotent for any given {{CacheObject}} ({{if (valBytes == null)}}).
> * Hand-written {{prepareMarshal(GridCacheSharedContext)}} overrides are removed from {{GridCacheMessage}} subclasses where the body was a pure {{@Order}}-CO traversal that the generator now performs:
> ** {{GridCacheTtlUpdateRequest}}, {{GridDhtForceKeysRequest}}, {{GridNearUnlockRequest}}, {{GridDhtUnlockRequest}}, {{GridDistributedLockRequest}}, {{GridDistributedLockResponse}}, {{GridDhtAtomicUpdateResponse}}, {{GridDhtAtomicNearResponse}}, {{GridNearGetRequest}}.
> ** Also dropped: {{ret.prepareMarshal(cctx)}} call inside {{GridNearAtomicUpdateResponse.prepareMarshal}} (covered by nested-message recursion in the generated serializer).
> * Generator hygiene aligned with Ignite coding guidelines: {{private static final}} modifier order, no trailing space after {{/**}} in class javadoc, no trailing newline at EOF, empty line between top-level {{if}}-blocks in {{prepareMarshalCacheObjects}}, empty line between map keys/values traversal blocks.
> h2. Why it is worth doing
> * *Structural coverage.* New {{@Order CO}} fields are picked up automatically; no risk of a missed override.
> * *Less boilerplate.* Phase 2 cleanup deletes ~9 hand-written methods that were doing the same loop the generator now writes.
> * *One source of truth* for "which fields participate in pre-marshal traversal" — the {{@Order}} annotations.
> * *No behavioural change* for messages whose hand-written override stays — the auto-invoke is a no-op on already-marshalled {{CacheObject}}s thanks to the {{valBytes == null}} guard inside {{CacheObjectImpl.prepareMarshal}}.
> h2. Out of scope
> * Receive-side counterpart ({{finishUnmarshalCacheObjects}}) — split into a separate ticket (IGNITE-YYYYY).
> * Extending the auto-invoke to {{GridCacheMessage}} subclasses that are not {{GridCacheIdMessage}} (e.g. {{GridDhtTxFinishResponse}}), or to nested messages whose embedded {{cacheId}} differs from the outer's (e.g. {{GridNearTxPrepareResponse}}'s {{retVal.cacheId()}}) — split into a separate ticket (IGNITE-ZZZZZ). Until that lands, {{GridCacheReturn}} keeps its {{static SER}} field and {{prepareMarshal(GridCacheContext)}} bridge for the two responses that fall outside the auto-invoke gate.
> h2. Acceptance criteria
> * {{GridCacheIoManager.onSend}} calls {{prepareMarshalGeneratedCacheObjects(msg)}} for every {{GridCacheIdMessage}} subclass with a non-{{null}} {{cacheObjectContext}}.
> * {{MessageProcessorTest}} green; fixture serializers byte-identical with generator output.
> * Targeted suites green: {{GridCacheReturnValueTransferSelfTest}}, {{IgniteCacheEntryProcessorCallTest}}, {{GridCachePartitionedTxMultiThreadedSelfTest}}, {{GridCacheRebalancingSyncSelfTest}} (force-keys path), {{GridCachePutAllFailoverSelfTest}} (atomic update / unlock path), {{IgniteCacheQueryMultiThreadedSelfTest}} (query/eviction path).
> * Possible-blockers list from the TC bot for the PR contains no real regressions (flakes only).



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