fix(serde): honor global serialization inclusion in generated serializers

[arimu1]

Description

Fixes micronaut-projects/micronaut-core#12838.

Source-generated serializers for simple @Serdeable beans/records always wrote every property (including null), so configuration such as:

micronaut:
  serde:
    serialization:
      inclusion: NON_NULL

had no effect. Runtime (CustomizedObjectSerializer / SerBean) already honored micronaut.serde.serialization.inclusion; the compile-time path did not.

Change

• Add GeneratedSerdeInclusionUtil for inclusion checks used by generated code
• Teach BeanSerializerSourceGen / RecordSerializerSourceGen to skip properties according to the active global inclusion (NON_NULL, NON_EMPTY, NON_ABSENT, NON_DEFAULT, NEVER, etc.)
• Keep generated serializers selected (no forced fallback to the runtime object serializer)

Workaround from the issue (disable-generated-serializer=true or type-level @JsonInclude) is no longer required for this case.

Related Issue

Fixes micronaut-projects/micronaut-core#12838

Type of Change

• Bug fix
• New feature
• Documentation update
• Improvement / performance

Checklist

• I have read the CONTRIBUTING guidelines
• Tests are included
• License headers present / Spotless applied

Testing

./gradlew :micronaut-serde-jackson:test
# SUCCESS: 1579 tests (15 skipped), JDK 26 (Homebrew openjdk@25)

Focused coverage:

• CompileTimeSourceGenSpec — global NON_NULL and default NON_EMPTY omit null/empty properties while still selecting generated serializers
• SerdeableGeneratedSpec — NON_NULL omits null name fields
• Recursive serialize tests set inclusion=ALWAYS when they assert explicit null output

[graemerocher]

@dstepanov we need to check this from a performance perspective

[Copilot]

🟡 Not ready to approve

GeneratedSerdeInclusionUtil.isDefaultScalar currently treats all Number zero values as default, which will incorrectly omit values like BigInteger(0) under NON_DEFAULT and needs adjustment (and ideally a focused test to lock the behavior in).

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Pull request overview

This PR fixes a gap in the compile-time (source-generated) serialization path so that generated bean/record serializers honor the global micronaut.serde.serialization.inclusion setting (e.g. NON_NULL, default NON_EMPTY) instead of always emitting all properties (including null).

Changes:

• Introduces GeneratedSerdeInclusionUtil to centralize global inclusion checks for generated serializers.
• Updates BeanSerializerSourceGen and RecordSerializerSourceGen to conditionally emit properties (including key emission) based on the active inclusion strategy.
• Adjusts/extends compile-time Jackson tests to validate generated serializer selection while asserting omission of null/empty properties under global inclusion.

File summaries

File	Description
serde-processor/src/main/java/io/micronaut/serde/processor/sourcegen/records/RecordSerializerSourceGen.java	Gates record component emission behind global inclusion checks (including primitive default handling).
serde-processor/src/main/java/io/micronaut/serde/processor/sourcegen/beans/BeanSerializerSourceGen.java	Gates bean property emission behind global inclusion checks (including primitive default handling).
serde-api/src/main/java/io/micronaut/serde/util/GeneratedSerdeInclusionUtil.java	Adds generated-code helper methods to evaluate global inclusion for scalar/primitive/serializer-backed properties.
serde-jackson/src/test/groovy/io/micronaut/serde/jackson/compiletime/SerdeableGeneratedSpec.groovy	Adds coverage for global NON_NULL and stabilizes tests needing explicit null output via ALWAYS.
serde-jackson/src/test/groovy/io/micronaut/serde/jackson/compiletime/CompileTimeSourceGenSpec.groovy	Adds global-inclusion assertions (NON_NULL, default NON_EMPTY) and introduces an ALWAYS helper for tests that assert null output.
serde-jackson/src/test/groovy/io/micronaut/serde/jackson/annotation/SerdeJsonSerializeDeserializeSpec.groovy	Forces ALWAYS inclusion for recursive serialization tests that assert explicit null fields.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 2
• Review effort level: Lite

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[arimu1]

Confirmed, this was real — fixed in 54c6aeb.

isDefaultScalar treated any Number with doubleValue() == 0d as default. That's inconsistent with this codebase's own runtime path: BigIntegerSerde/BigDecimalSerde (both NumberSerde implementations) never override Serializer#isDefault, so the default impl (return false) applies — CustomizedObjectSerializer's NON_DEFAULT branch (serializer.isDefault(...)) never treats BigInteger/BigDecimal as default regardless of value. Meanwhile BeanSerializerSourceGen/RecordSerializerSourceGen#scalarEncoderMethod route BigInteger/BigDecimal properties through this exact fast path (via ENCODE_BIG_INTEGER_METHOD/ENCODE_BIG_DECIMAL_METHOD), so the bug was reachable for real generated serializers, not just a theoretical gap.

Fix: isDefaultScalar now only treats zero as default for the boxed primitive-wrapper number types that actually override isDefault with a zero check (Byte/Short/Integer/Long/Float/Double — see IntegerSerde, LongSerde, etc.), leaving BigInteger/BigDecimal/other Number types non-default, matching the runtime serializer path.

Added a compile-time test (test generated serializers honor global inclusion NON_DEFAULT for BigInteger and BigDecimal zero in CompileTimeSourceGenSpec.groovy, using a new SourceGenNonDefaultScalarBean fixture) that fails before the fix (BigInteger.ZERO/BigDecimal.ZERO silently omitted) and passes after.