AGENTS.md

1# ES|QL Compute Engine
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3## Code generation
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5Most classes in this module are generated via two mechanisms:
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71. **StringTemplate** (`*.java.st` files)
82. **Annotation processors** (`compute/gen`) — classes annotated with `@Evaluator`,
9   `@Aggregator`, `@GroupingAggregator`, etc. are generated at compile time automatically.
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11Do not hand-edit generated files. Edit the template or annotated source instead.
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13## Hand-written classes
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15Some classes are hand-written across multiple type variants instead of generated.
16Two rules apply:
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18- When changing one variant, keep all variants in sync.
19- When changing annotation processors or generated output, update hand-written classes
20  to stay consistent with the new generated code.
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22Hand-written families:
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24- `Rate*GroupingAggregatorFunction` — `IncreaseExponentialHistogramGroupingAggregatorFunction` also belongs to this family.
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