feat: support Spark expression json_array_length#4365
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kazantsev-maksim wants to merge 47 commits into
Open
feat: support Spark expression json_array_length#4365kazantsev-maksim wants to merge 47 commits into
kazantsev-maksim wants to merge 47 commits into
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This reverts commit 768b3e9.
andygrove
reviewed
May 20, 2026
| classOf[Cast] -> CometCast) | ||
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| private val jsonExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map( | ||
| classOf[LengthOfJsonArray] -> CometScalarFunction("json_array_length")) |
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Spark's JsonExpressionUtils.lengthOfJsonArray uses a Jackson parser configured with
ALLOW_SINGLE_QUOTES and ALLOW_UNESCAPED_CONTROL_CHARS, and uses streaming parsing that ignores trailing content after the array's closing bracket. serde_json::from_str::<Value> is much stricter. Could you mark getSupportLevel as Incompatible(Some("...")) and add getIncompatibleReasons() so that the auto-generated compat doc surfaces the limitation to users, and the function is gated behind spark.comet.expression.LengthOfJsonArray.allowIncompatible=true.
andygrove
reviewed
May 20, 2026
| SELECT json_array_length('not an array') | ||
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| query | ||
| SELECT json_array_length('{"key":"value"}') |
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could you also add examples for incompatible behavior, such as using single quotes around keys and values
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Which issue does this PR close?
Closes #.
Rationale for this change
Add native support for Spark's json_array_length(jsonArray) expression so it runs on Comet instead of falling back to Spark.
What changes are included in this PR?
How are these changes tested?
New SQL test file spark/src/test/resources/sql-tests/expressions/json/json_array_length.sql