mark compactable

Author: leung-ming

docs/source/user-guide/compatibility.md

@@ -174,13 +174,15 @@ The following cast operations are generally compatible with Spark except for the
 | float | integer |  |
 | float | long |  |
 | float | double |  |
+| float | decimal |  |
 | float | string | There can be differences in precision. For example, the input "1.4E-45" will produce 1.0E-45 instead of 1.4E-45 |
 | double | boolean |  |
 | double | byte |  |
 | double | short |  |
 | double | integer |  |
 | double | long |  |
 | double | float |  |
+| double | decimal |  |
 | double | string | There can be differences in precision. For example, the input "1.4E-45" will produce 1.0E-45 instead of 1.4E-45 |
 | decimal | byte |  |
 | decimal | short |  |
@@ -210,8 +212,6 @@ The following cast operations are not compatible with Spark for all inputs and a
 |-|-|-|
 | integer | decimal  | No overflow check |
 | long | decimal  | No overflow check |
-| float | decimal  | There can be rounding differences |
-| double | decimal  | There can be rounding differences |
 | string | float  | Does not support inputs ending with 'd' or 'f'. Does not support 'inf'. Does not support ANSI mode. |
 | string | double  | Does not support inputs ending with 'd' or 'f'. Does not support 'inf'. Does not support ANSI mode. |
 | string | decimal  | Does not support inputs ending with 'd' or 'f'. Does not support 'inf'. Does not support ANSI mode. Returns 0.0 instead of null if input contains no digits |

spark/src/main/scala/org/apache/comet/expressions/CometCast.scala

@@ -262,19 +262,15 @@ object CometCast {
     case DataTypes.BooleanType | DataTypes.DoubleType | DataTypes.ByteType | DataTypes.ShortType |
         DataTypes.IntegerType | DataTypes.LongType =>
       Compatible()
-    case _: DecimalType =>
-      // https://github.com/apache/datafusion-comet/issues/1371
-      Incompatible(Some("There can be rounding differences"))
+    case _: DecimalType => Compatible()
     case _ => Unsupported
   }
 
   private def canCastFromDouble(toType: DataType): SupportLevel = toType match {
     case DataTypes.BooleanType | DataTypes.FloatType | DataTypes.ByteType | DataTypes.ShortType |
         DataTypes.IntegerType | DataTypes.LongType =>
       Compatible()
-    case _: DecimalType =>
-      // https://github.com/apache/datafusion-comet/issues/1371
-      Incompatible(Some("There can be rounding differences"))
+    case _: DecimalType => Compatible()
     case _ => Unsupported
   }
 

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

@@ -411,17 +411,10 @@ class CometCastSuite extends CometTestBase with AdaptiveSparkPlanHelper {
     castTest(generateFloats(), DataTypes.DoubleType)
   }
 
-  ignore("cast FloatType to DecimalType(10,2)") {
-    // // https://github.com/apache/datafusion-comet/issues/1371
+  test("cast FloatType to DecimalType(10,2)") {
     castTest(generateFloats(), DataTypes.createDecimalType(10, 2))
   }
 
-  test("cast FloatType to DecimalType(10,2) - allow incompat") {
-    withSQLConf(CometConf.COMET_CAST_ALLOW_INCOMPATIBLE.key -> "true") {
-      castTest(generateFloats(), DataTypes.createDecimalType(10, 2))
-    }
-  }
-
   test("cast FloatType to StringType") {
     // https://github.com/apache/datafusion-comet/issues/312
     val r = new Random(0)
@@ -471,17 +464,10 @@ class CometCastSuite extends CometTestBase with AdaptiveSparkPlanHelper {
     castTest(generateDoubles(), DataTypes.FloatType)
   }
 
-  ignore("cast DoubleType to DecimalType(10,2)") {
-    // https://github.com/apache/datafusion-comet/issues/1371
+  test("cast DoubleType to DecimalType(10,2)") {
     castTest(generateDoubles(), DataTypes.createDecimalType(10, 2))
   }
 
-  test("cast DoubleType to DecimalType(10,2) - allow incompat") {
-    withSQLConf(CometConf.COMET_CAST_ALLOW_INCOMPATIBLE.key -> "true") {
-      castTest(generateDoubles(), DataTypes.createDecimalType(10, 2))
-    }
-  }
-
   test("cast DoubleType to StringType") {
     // https://github.com/apache/datafusion-comet/issues/312
     val r = new Random(0)