Revert "added IT , add null cases, fixed format for integer/big integer"

Signed-off-by: Asif Bashar <asif.bashar@gmail.com>

Author: asifabashar

core/src/main/java/org/opensearch/sql/expression/function/udf/ToNumberFunction.java

@@ -50,24 +50,50 @@ public SqlReturnTypeInference getReturnTypeInference() {
     return (opBinding) -> {
       // Try to determine if the result will be Long or Double based on the input
       int base = 10;
-      try {
-        base =
-            opBinding.getOperandCount() > 1
-                ? opBinding.getOperandLiteralValue(1, Integer.class)
-                : 10;
-      } catch (NumberFormatException e) {
-        // If parsing fails, default to  base 10
+      if (opBinding.getOperandCount() > 1) {
+
+        base = opBinding.getOperandLiteralValue(1, Integer.class);
       }
+
       if (opBinding.getOperandCount() > 0 && opBinding.isOperandLiteral(0, false)) {
         String literal = opBinding.getOperandLiteralValue(0, String.class);
         if (literal != null) {
-
-          // Check if it's a decimal number
-          if (base != 10 || !(literal.contains("."))) {
+          try {
+            // Check if it's a decimal number
+            if (base != 10) {
+              return opBinding
+                  .getTypeFactory()
+                  .createTypeWithNullability(
+                      opBinding.getTypeFactory().createSqlType(SqlTypeName.BIGINT), true);
+            }
+            if (literal.contains(".")) {
+              return opBinding
+                  .getTypeFactory()
+                  .createTypeWithNullability(
+                      opBinding
+                          .getTypeFactory()
+                          .createSqlType(org.apache.calcite.sql.type.SqlTypeName.DOUBLE),
+                      true);
+            } else {
+              // Check if it's an integer that fits in Long
+              Long.parseLong(literal);
+              return opBinding
+                  .getTypeFactory()
+                  .createTypeWithNullability(
+                      opBinding
+                          .getTypeFactory()
+                          .createSqlType(org.apache.calcite.sql.type.SqlTypeName.BIGINT),
+                      true);
+            }
+          } catch (NumberFormatException e) {
+            // If parsing fails, default to Double (matches the runtime behavior)
             return opBinding
                 .getTypeFactory()
                 .createTypeWithNullability(
-                    opBinding.getTypeFactory().createSqlType(SqlTypeName.BIGINT), true);
+                    opBinding
+                        .getTypeFactory()
+                        .createSqlType(org.apache.calcite.sql.type.SqlTypeName.DOUBLE),
+                    true);
           }
         }
       }

core/src/test/java/org/opensearch/sql/expression/function/udf/ToNumberFunctionTest.java

@@ -7,13 +7,19 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
+import org.apache.calcite.sql.type.ReturnTypes;
 import org.junit.jupiter.api.Test;
 import org.opensearch.sql.calcite.utils.PPLOperandTypes;
 
 public class ToNumberFunctionTest {
 
   private final ToNumberFunction function = new ToNumberFunction();
 
+  @Test
+  void testGetReturnTypeInference() {
+    assertEquals(ReturnTypes.DOUBLE_FORCE_NULLABLE, function.getReturnTypeInference());
+  }
+
   @Test
   void testGetOperandMetadata() {
     assertEquals(PPLOperandTypes.STRING_OR_STRING_INTEGER, function.getOperandMetadata());