fix: deserialize Java records when Multi-Release classes are unavailable - #2131
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arimu1 wants to merge 1 commit into
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fix: deserialize Java records when Multi-Release classes are unavailable#2131arimu1 wants to merge 1 commit into
arimu1 wants to merge 1 commit into
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maven-shade-plugin (and similar fat-jar tools) often rewrite the jar manifest and drop Multi-Release: true while leaving META-INF/versions/16 in place. The JVM then loads the base RecordJsonAdapter stub, which returned null and fell through to ClassJsonAdapter — causing AssertionError for Java records (square#2117). Implement record support in the base adapter via reflective access to Class.isRecord / getRecordComponents so records work even without Multi-Release selection. The typed java16 implementation remains preferred when Multi-Release is intact. Fixes square#2117
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Summary
Fixes #2117 —
AssertionErrorwhen deserializing Java records after packaging withmaven-shade-plugin.Root cause
Moshi ships
RecordJsonAdapteras a Multi-Release JAR:RecordJsonAdapter): stub whose factory always returnednullMETA-INF/versions/16/: real record supportmaven-shade-plugincommonly rewrites the jar manifest (e.g. only settingMain-Class) and dropsMulti-Release: true, while still copyingMETA-INF/versions/16/. Without that manifest flag the JVM ignores the versioned classes and loads the stub. The factory returnsnull, Moshi falls through toClassJsonAdapter, and field assignment on a record fails withIllegalAccessException→ bareAssertionError.Confirmed: the same shaded jar works once
Multi-Release: trueis restored on the manifest.Fix
Implement record support in the base
RecordJsonAdapterusing reflective access toClass.isRecord()/getRecordComponents()(and related APIs). That keeps--release 8compilation while making records work on JDK 16+ even when Multi-Release classes are not selected.The typed implementation under
src/main/java16is unchanged and remains preferred when Multi-Release packaging is intact.Test plan
./gradlew :moshi:records-tests:test(includes newsimpleRecordFromJson)./gradlew :moshi:test./gradlew spotlessCheckMulti-Releasein fat-jar manifest):AssertionErroratClassJsonAdapter.fromJson2.0.0-SNAPSHOTvia mavenLocal): printsFoo[bar=baz]Notes
Preserving
Multi-Release: truein shade config remains a good practice (selects the typed JDK 16 implementation), but is no longer required for record deserialization to work.