feat: support url_decode expression via StaticInvoke

native/core/src/execution/jni_api.rs

@@ -55,6 +55,7 @@ use datafusion_spark::function::math::hex::SparkHex;
 use datafusion_spark::function::math::width_bucket::SparkWidthBucket;
 use datafusion_spark::function::string::char::CharFunc;
 use datafusion_spark::function::string::concat::SparkConcat;
+use datafusion_spark::function::url::url_decode::UrlDecode;
 use futures::poll;
 use futures::stream::StreamExt;
 use jni::objects::JByteBuffer;
@@ -400,6 +401,7 @@ fn register_datafusion_spark_function(session_ctx: &SessionContext) {
     session_ctx.register_udf(ScalarUDF::new_from_impl(SparkWidthBucket::default()));
     session_ctx.register_udf(ScalarUDF::new_from_impl(MapFromEntries::default()));
     session_ctx.register_udf(ScalarUDF::new_from_impl(SparkCrc32::default()));
+    session_ctx.register_udf(ScalarUDF::new_from_impl(UrlDecode::default()));
 }
 
 /// Prepares arrow arrays for output.

spark/src/main/scala/org/apache/comet/serde/statics.scala

@@ -19,11 +19,13 @@
 
 package org.apache.comet.serde
 
-import org.apache.spark.sql.catalyst.expressions.Attribute
+import org.apache.spark.sql.catalyst.expressions.{Attribute, UrlCodec}
 import org.apache.spark.sql.catalyst.expressions.objects.StaticInvoke
 import org.apache.spark.sql.catalyst.util.CharVarcharCodegenUtils
 
 import org.apache.comet.CometSparkSessionExtensions.withInfo
+import org.apache.comet.serde.ExprOuterClass.Expr
+import org.apache.comet.serde.QueryPlanSerde.{exprToProtoInternal, optExprWithInfo, scalarFunctionExprToProtoWithReturnType}
 
 object CometStaticInvoke extends CometExpressionSerde[StaticInvoke] {
 
@@ -34,7 +36,8 @@ object CometStaticInvoke extends CometExpressionSerde[StaticInvoke] {
       : Map[(String, Class[_]), CometExpressionSerde[StaticInvoke]] =
     Map(
       ("readSidePadding", classOf[CharVarcharCodegenUtils]) -> CometScalarFunction(
-        "read_side_padding"))
+        "read_side_padding"),
+      ("decode", UrlCodec.getClass) -> CometUrlDecode)
 
   override def convert(
       expr: StaticInvoke,
@@ -52,3 +55,21 @@ object CometStaticInvoke extends CometExpressionSerde[StaticInvoke] {
     }
   }
 }
+
+/**
+ * Handler for UrlCodec.decode StaticInvoke (Spark 3.4+). Maps to datafusion-spark's built-in
+ * url_decode function.
+ */
+private object CometUrlDecode extends CometExpressionSerde[StaticInvoke] {
+
+  override def convert(
+      expr: StaticInvoke,
+      inputs: Seq[Attribute],
+      binding: Boolean): Option[Expr] = {
+    // StaticInvoke args: [child, Literal("UTF-8")] — only serialize the first
+    val childExpr = exprToProtoInternal(expr.arguments.head, inputs, binding)
+    val optExpr =
+      scalarFunctionExprToProtoWithReturnType("url_decode", expr.dataType, false, childExpr)
+    optExprWithInfo(optExpr, expr, expr.arguments.head)
+  }
+}

spark/src/test/scala/org/apache/comet/CometStringExpressionSuite.scala

@@ -478,4 +478,35 @@ class CometStringExpressionSuite extends CometTestBase {
     }
   }
 
+  test("url_decode") {
+    val data = Seq(
+      "https%3A%2F%2Fspark.apache.org", // percent-encoded URL
+      "hello+world", // plus as space
+      "%E4%B8%AD%E6%96%87", // multi-byte UTF-8 (Chinese)
+      "no+encoding+needed", // spaces only
+      "%e4%b8%ad", // lowercase hex digits
+      "abc%20def%21%40%23", // mixed encoded/unencoded
+      "%F0%9F%94%A5", // 4-byte UTF-8 (emoji)
+      "already+decoded+%2B+literal+plus", // encoded plus sign (%2B)
+      "").map(Tuple1(_))
+    withParquetTable(data, "tbl") {
+      checkSparkAnswerAndOperator("SELECT url_decode(_1) FROM tbl")
+    }
+  }
+
+  test("url_decode - null handling") {
+    withParquetTable(
+      Seq(Some("hello+world"), None, Some("%E4%B8%AD")).map(v => Tuple1(v.orNull)),
+      "tbl") {
+      checkSparkAnswerAndOperator("SELECT url_decode(_1) FROM tbl")
+    }
+  }
+
+  test("url_decode - literals") {
+    withParquetTable(Seq(Tuple1(1)), "tbl") {
+      checkSparkAnswerAndOperator("SELECT url_decode('hello%20world') FROM tbl")
+      checkSparkAnswerAndOperator("SELECT url_decode('%E4%B8%AD%E6%96%87') FROM tbl")
+    }
+  }
+
 }