[SPARK-35104][SQL] Fix ugly indentation of multiple JSON records in a…

… single split file generated by JacksonGenerator when pretty option is true

### What changes were proposed in this pull request?

This issue fixes an issue that indentation of multiple output JSON records in a single split file are broken except for the first record in the split when `pretty` option is `true`.
```
// Run in the Spark Shell.
// Set spark.sql.leafNodeDefaultParallelism to 1 for the current master.
// Or set spark.default.parallelism for the previous releases.
spark.conf.set("spark.sql.leafNodeDefaultParallelism", 1)
val df = Seq("a", "b", "c").toDF
df.write.option("pretty", "true").json("/path/to/output")

# Run in a Shell
$ cat /path/to/output/*.json
{
  "value" : "a"
}
 {
  "value" : "b"
}
 {
  "value" : "c"
}
```

### Why are the changes needed?

It's not pretty even though `pretty` option is true.

### Does this PR introduce _any_ user-facing change?

I think "No". Indentation style is changed but JSON format is not changed.

### How was this patch tested?

New test.

Closes #32203 from sarutak/fix-ugly-indentation.

Authored-by: Kousuke Saruta <[email protected]>
Signed-off-by: Max Gekk <[email protected]>

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JacksonGenerator.scala

@@ -20,6 +20,7 @@ package org.apache.spark.sql.catalyst.json
 import java.io.Writer
 
 import com.fasterxml.jackson.core._
+import com.fasterxml.jackson.core.util.DefaultPrettyPrinter
 
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.SpecializedGetters
@@ -73,7 +74,7 @@ private[sql] class JacksonGenerator(
 
   private val gen = {
     val generator = new JsonFactory().createGenerator(writer).setRootValueSeparator(null)
-    if (options.pretty) generator.useDefaultPrettyPrinter() else generator
+    if (options.pretty) generator.setPrettyPrinter(new DefaultPrettyPrinter("")) else generator
   }
 
   private val lineSeparator: String = options.lineSeparatorInWrite

sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala

@@ -2844,6 +2844,31 @@ abstract class JsonSuite
       assert(readback.collect sameElements Array(Row(0), Row(1), Row(2)))
     }
   }
+
+  test("SPARK-35104: Fix wrong indentation for multiple JSON even if `pretty` option is true") {
+    withSQLConf(SQLConf.LEAF_NODE_DEFAULT_PARALLELISM.key -> "1") {
+      withTempPath { path =>
+        val basePath = path.getCanonicalPath
+        val df = Seq("a", "b", "c").toDF
+        df.write.option("pretty", "true").json(basePath)
+
+        val expectedText =
+          s"""{
+             |  "value" : "a"
+             |}
+             |{
+             |  "value" : "b"
+             |}
+             |{
+             |  "value" : "c"
+             |}
+             |""".stripMargin
+        val actualText = spark.read.option("wholetext", "true")
+          .text(basePath).map(_.getString(0)).collect().mkString
+        assert(actualText === expectedText)
+      }
+    }
+  }
 }
 
 class JsonV1Suite extends JsonSuite {