fix(parquet): strip repetition_type from root SchemaElement during serialization#723
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hcrosse wants to merge 2 commits intoapache:mainfrom
Open
fix(parquet): strip repetition_type from root SchemaElement during serialization#723hcrosse wants to merge 2 commits intoapache:mainfrom
hcrosse wants to merge 2 commits intoapache:mainfrom
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…rialization The Parquet spec states the root of the schema does not have a repetition_type. arrow-go was writing REPEATED for the root SchemaElement in the Thrift footer, which is non-standard and breaks interoperability with consumers like Snowflake. Strip RepetitionType from the root element in ToThrift(), matching parquet-java and arrow-rs behavior. The in-memory representation and WithRootRepetition API are unaffected. FromParquet already tolerates a nil root repetition type, so this is backwards-compatible for both readers and writers. Closes apache#722
…ping Stripping the root SchemaElement's repetition_type removes 2 bytes from the serialized Thrift footer (field header + enum value).
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Rationale
The Parquet spec says the root of the schema doesn't have a
repetition_type. arrow-go writesREPEATEDfor the rootSchemaElementin the Thrift footer, which breaks interop with consumers like Snowflake. #722 has the full writeup and cross-implementation comparison.What changes are included in this PR?
ToThrift()now nils outRepetitionTypeon the root element before returning, stripping it from the serialized output. This matches how parquet-java and arrow-rs handle the root.The in-memory representation and
WithRootRepetitionAPI are unaffected.FromParquetalready tolerates a nil root repetition type, so this is backwards-compatible for both readers and writers.Are these changes tested?
Updated the existing
TestNestedExampleand addedTestToThriftRootRepetitionStrippedwhich checks that the root'srepetition_typeis stripped for all three repetition variants and that non-root elements keep theirs.Closes #722