From 554665f00486bb880010bf79a3fd1f077c3022a5 Mon Sep 17 00:00:00 2001
From: gs-jp1 <80327721+gs-jp1@users.noreply.github.com>
Date: Wed, 6 Dec 2023 14:41:03 +0000
Subject: [PATCH] Legend SQL - Handle null valuespecifications correctly in
 cast (#2499)

---
 .../binding/fromPure/fromPure.pure                       | 9 +++++----
 .../binding/fromPure/tests/testTranspile.pure            | 7 +++++--
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/fromPure.pure b/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/fromPure.pure
index 6baecee1be0..189a6656376 100644
--- a/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/fromPure.pure
+++ b/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/fromPure.pure
@@ -1585,9 +1585,10 @@ function <<access.private>> meta::external::query::sql::transformation::queryToP
 
   let expression = processExpression($c.expression, $expContext, $context);
 
-  $c.expression->match([
-    n:NullLiteral[1] | processCastAsCast($c, $expression, $expContext, $context),
-    e:meta::external::query::sql::metamodel::Expression[1] |
+  if ($expression->evaluateAndDeactivate().multiplicity == PureZero,
+    | 
+      processCastAsCast($c, $expression, $expContext, $context),
+    | 
       let type = $expression.genericType.rawType->toOne();
       let castName = $c.type.name->toUpper();
 
@@ -1598,7 +1599,7 @@ function <<access.private>> meta::external::query::sql::transformation::queryToP
         pair($type == String || $castName == 'TEXT', | processCastAsParse($c, $expression, $expContext, $context)),
         pair(true, | processCastAsCast($c, $expression, $expContext, $context))
       ]->getValues(true)->first()->toOne()->eval()->evaluateAndDeactivate();
-  ]);
+    );
 }
 
 function <<access.private>> meta::external::query::sql::transformation::queryToPure::processDoublePrecisionCast(c:Cast[1], v:ValueSpecification[1], expContext:SqlTransformExpressionContext[1], context:SqlTransformContext[1]):ValueSpecification[1]
diff --git a/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/tests/testTranspile.pure b/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/tests/testTranspile.pure
index 3b18da5beb8..24131ddf746 100644
--- a/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/tests/testTranspile.pure
+++ b/legend-engine-xts-sql/legend-engine-xt-sql-pure/src/main/resources/core_external_query_sql/binding/fromPure/tests/testTranspile.pure
@@ -1051,7 +1051,9 @@ function <<test.Test>> meta::external::query::sql::transformation::queryToPure::
 function <<test.Test>> meta::external::query::sql::transformation::queryToPure::tests::testNullCasts():Boolean[1]
 {
   test('SELECT CAST(NULL AS VARCHAR) AS "string", CAST(NULL AS TEXT) AS "text", CAST(NULL AS DATE) AS "date", ' +
-       'CAST(NULL AS INTEGER) AS "integer", CAST(NULL AS BOOLEAN) AS "boolean", CAST(NULL AS DOUBLE PRECISION) AS "double", CAST(NULL AS NUMERIC) AS "numeric", CAST(NULL AS TIMESTAMP) AS "timestamp" FROM service."/service/service1"',
+       'CAST(NULL AS INTEGER) AS "integer", CAST(NULL AS BOOLEAN) AS "boolean", CAST(NULL AS DOUBLE PRECISION) AS "double", ' + 
+       'CAST(NULL AS NUMERIC) AS "numeric", CAST(NULL AS TIMESTAMP) AS "timestamp", CAST(floor(NULL) AS TEXT) AS "exp" ' + 
+       'FROM service."/service/service1"',
 
       {| FlatInput.all()->project(
           [ x | $x.booleanIn, x | $x.integerIn, x | $x.floatIn, x | $x.decimalIn, x | $x.strictDateIn, x | $x.dateTimeIn, x | $x.stringIn ],
@@ -1064,7 +1066,8 @@ function <<test.Test>> meta::external::query::sql::transformation::queryToPure::
           col(row:TDSRow[1] | cast([], @Boolean), 'boolean'),
           col(row:TDSRow[1] | cast([], @Float), 'double'),
           col(row:TDSRow[1] | cast([], @Decimal), 'numeric'),
-          col(row:TDSRow[1] | cast([], @DateTime), 'timestamp')
+          col(row:TDSRow[1] | cast([], @DateTime), 'timestamp'),
+          col(row:TDSRow[1] | cast([], @String), 'exp')
         ])
       })
 }