STRICT_DUPLICATE_DETECTION rejects repeated XML elements read by a custom deserializer

Aperta
  • Qualcosa non va?
#931 3 commenti 0 reazioni 0 assegnatari Vedi su GitHub

Nessuno ha ancora preso questa issue.

Valutazione

Difficoltà
4/5
Tempo stimato
3-5 giorni
Idoneità per principianti
45/100
Tipo di issue
Bug
Chiarezza
Specificata chiaramente
Stato di attività
Attiva
Stack tecnologico
java
Ambito
api, backend

Direzione di ricerca

Start with StrictDuplicateDetectionXmlTest and trace FromXmlParser token handling into the duplicate-name check in JsonReadContext, focusing on how repeated XML elements are represented before readValueAsTree() builds the tree. Run the three listed JUnit cases to confirm the failure and controls. Done means the custom-deserializer case with strict detection enabled preserves both OU values while the declared-List and strict-disabled controls still pass.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Descrizione

Summary

In XML, sibling elements with the same name are legitimate and normally map to a list. When such repeats are bound to a declared List property, STRICT_DUPLICATE_DETECTION correctly tolerates them (they are coalesced into the list). But when the same repeats are consumed by a custom deserializer that materializes the element with JsonParser.readValueAsTree(), enabling STRICT_DUPLICATE_DETECTION makes the read fail with:

tools.jackson.core.exc.StreamReadException: Duplicate Object property "OU"

A repeated XML element is thus reported as a duplicate object property. This makes STRICT_DUPLICATE_DETECTION effectively incompatible with any element whose child tag names are dynamic/heterogeneous and must be read as a tree — a Distinguished Name is the canonical example:

<Dn>
    <C>FR</C>
    <O>ACME</O>
    <OU>Sales</OU>
    <OU>EMEA</OU>   <!-- legitimate repeat; rejected under STRICT -->
    <CN>leaf</CN>
</Dn>

Because the RDN tag names differ (C, O, OU, CN), the element cannot be bound to a single declared List, so a custom deserializer is required — and that path is broken by the feature.

How to reproduce

./gradlew test     # the three JUnit cases below
./gradlew run      # prints the three cases

run output:

1) declared List + STRICT on  -> OK     [Sales, EMEA]
2) custom deser  + STRICT off  -> OK     [Rdn[type=C, value=FR], Rdn[type=O, value=ACME], Rdn[type=OU, value=Sales], Rdn[type=OU, value=EMEA], Rdn[type=CN, value=leaf]]
3) custom deser  + STRICT on   -> FAILS  StreamReadException: Duplicate Object property "OU"

StrictDuplicateDetectionXmlTest:

  1. repeatedElementsBoundToDeclaredListAreToleratedUnderStrict — control: declared List + STRICT → OK.
  2. repeatedElementsViaCustomDeserializerWorkWithoutStrict — control: custom deserializer, STRICT off → OK (both <OU> kept).
  3. repeatedElementsViaCustomDeserializerFailUnderStrict — the issue: same input, STRICT on → StreamReadException: Duplicate Object property "OU".

Actual behaviour

STRICT_DUPLICATE_DETECTION fires at the streaming/token level (JsonReadContext duplicate name check) as soon as the second <OU> name is seen, before the XML module coalesces the repeats into an array — so the tree is never built.

Expected behaviour

Reading the element via readValueAsTree() should coalesce the repeated <OU> siblings into an ArrayNode (as it already does when STRICT_DUPLICATE_DETECTION is disabled), rather than reporting them as a duplicate object property. Repeated XML elements are not JSON-style duplicate keys.

Additional information

Within the custom deserializer, every way of consuming the element goes through the strict parser and triggers the same detection: readValueAsTree(), manual nextToken() streaming, @JsonAnySetter, TokenBuffer.copyCurrentStructure(...), and skipChildren(). Reading the underlying Stax XMLStreamReader directly avoids the detection but desynchronises FromXmlParser (one-token lookahead), breaking the outer parse. The feature therefore cannot be kept while deserializing such an element.

A Gradle projet that illustrates this issue is attached to the ticket:
jackson-xml-strict-duplicate-dn-sources.zip

Lingua principale
Java
Stelle
636
Fork
250
Merge medio
7h 10m
PR unite (30g)
8

Preparare l'ambiente

Questo progetto non fornisce container di sviluppo, Dockerfile né guida per i contributori, quindi l'ambiente è a tuo carico: parti dal suo README e consulta la nostra guida al primo contributo per i passaggi generali.

Come iniziare

  1. Leggi tutta la issue e poi la guida ai contributi del progetto.
  2. Commenta sulla issue per dire che te ne occupi tu — evita che due persone facciano lo stesso lavoro.
  3. Fai un fork del repository e lavora su un branch.
  4. Apri una pull request che faccia riferimento al numero della issue.

Altre issue di FasterXML/jackson-dataformat-xml

Tutte le issue di FasterXML/jackson-dataformat-xml

Issue simili

Altre issue su Java

Ricevi le nuove issue nella tua casella

Un breve riepilogo di issue GitHub adatte ai principianti.