Fix codegen for WriteAggregate with OnMissing.ThrowException and batch queries#2390
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jeremydmiller merged 1 commit intomainfrom Mar 31, 2026
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…hing When using [WriteAggregate(OnMissing = ThrowException)] with UseIdentityMapForAggregates and a Validate() middleware method, the codegen generated guard frames that referenced stream_entity before it was declared. The batch query enrolled the LoadAggregateFrame but the variable declaration (var stream_entity = await ...BatchItem) was not emitted until after the guard frames had already tried to use stream_entity.Aggregate. The fix adds GenerateCodeForBatchResolution() to LoadAggregateFrame which is called by MartenBatchFrame after the batch execute completes, ensuring the stream variable is declared before any guard frames reference it. Fixes #2387 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This was referenced Apr 1, 2026
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Summary
Fixes #2387
[WriteAggregate(OnMissing = ThrowException)]withUseIdentityMapForAggregates = trueand aValidate()middleware method, the Marten batch query policy enrolled theLoadAggregateFramein a batch but didn't emit the variable declaration (var stream_entity = await stream_entity_BatchItem) until after guard frames had already tried to referencestream_entity.Aggregate, causingCS0841: Cannot use local variable before it is declared.GenerateCodeForBatchResolution()toLoadAggregateFrame, called byMartenBatchFrameimmediately afterbatchQuery.Execute(). This ensures the stream variable is declared before any guard frames (null checks, Validate calls) reference it. The originalGenerateCode()skips re-declaration when batch resolution has already run.Key conditions to reproduce
All three must be present:
[WriteAggregate(OnMissing = OnMissing.ThrowException)]on a message handler (not HTTP endpoint)UseIdentityMapForAggregates = true(no snapshot projection)Validate()middleware method that takes the aggregate as a parameterTest plan
🤖 Generated with Claude Code