Fix case when input expr is null

vtl-engine/src/main/java/fr/insee/vtl/engine/visitors/expression/ConditionalVisitor.java

@@ -5,6 +5,7 @@
 
 import fr.insee.vtl.engine.exceptions.VtlRuntimeException;
 import fr.insee.vtl.engine.visitors.expression.functions.GenericFunctionsVisitor;
+import fr.insee.vtl.model.ConstantExpression;
 import fr.insee.vtl.model.Positioned;
 import fr.insee.vtl.model.ResolvableExpression;
 import fr.insee.vtl.model.exceptions.InvalidTypeException;
@@ -165,11 +166,14 @@ private ResolvableExpression caseToIfIt(
     }
 
     ResolvableExpression nextWhen = whenExpr.next();
+    ResolvableExpression caseCondition =
+        genericFunctionsVisitor.invokeFunction(
+            "nvl", List.of(nextWhen, new ConstantExpression(false, nextWhen)), nextWhen);
 
     return genericFunctionsVisitor.invokeFunction(
         "ifThenElse",
-        List.of(nextWhen, thenExpr.next(), caseToIfIt(whenExpr, thenExpr, elseExpression)),
-        nextWhen);
+        List.of(caseCondition, thenExpr.next(), caseToIfIt(whenExpr, thenExpr, elseExpression)),
+        caseCondition);
   }
 
   /**

vtl-engine/src/test/java/fr/insee/vtl/engine/visitors/expression/ConditionalExprTest.java

@@ -69,6 +69,8 @@ public void testCaseExpr() throws ScriptException {
     assertThat(context.getAttribute("s2")).isEqualTo("yes");
     engine.eval("s3 := case when false then \"no\" when 1=2 then \"yes\" else \"else\";");
     assertThat(context.getAttribute("s3")).isEqualTo("else");
+    engine.eval("s4 := case when cast(null, boolean) then \"no\" else \"else\";");
+    assertThat(context.getAttribute("s4")).isEqualTo("else");
 
     engine.getContext().setAttribute("ds_1", DatasetSamples.ds1, ScriptContext.ENGINE_SCOPE);
     engine.getContext().setAttribute("ds_2", DatasetSamples.ds2, ScriptContext.ENGINE_SCOPE);

vtl-spark/src/test/java/fr/insee/vtl/spark/processing.engine/CalcTest.java

@@ -6,6 +6,7 @@
 import fr.insee.vtl.model.Dataset;
 import fr.insee.vtl.model.InMemoryDataset;
 import fr.insee.vtl.model.Structured;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import javax.script.ScriptContext;
@@ -79,4 +80,40 @@ public void testCalcClause() throws ScriptException, InterruptedException {
             new Structured.Component("weight", Long.class, Dataset.Role.MEASURE),
             new Structured.Component("wisdom", Double.class, Dataset.Role.ATTRIBUTE));
   }
+
+  @Test
+  public void testCaseElseAppliesWhenWhenConditionIsNull() throws ScriptException {
+    ScriptContext context = engine.getContext();
+
+    Map<String, Object> r4 = new HashMap<>();
+    r4.put("name", "NullGuy");
+    r4.put("me_1", null);
+
+    InMemoryDataset dsWithNull =
+        new InMemoryDataset(
+            List.of(
+                Map.of("name", "A", "me_1", 0.12D),
+                Map.of("name", "B", "me_1", 3.5D),
+                Map.of("name", "C", "me_1", 10.7D),
+                r4),
+            Map.of("name", String.class, "me_1", Double.class),
+            Map.of("name", Dataset.Role.IDENTIFIER, "me_1", Dataset.Role.MEASURE));
+
+    context.setAttribute("ds_null", dsWithNull, ScriptContext.ENGINE_SCOPE);
+    engine.eval(
+        "res := ds_null[calc me_2 := case when me_1 <= 1 then 0 when me_1 > 1 and me_1 <= 10 then 1 when me_1 > 10 then 10 else 100];");
+
+    Dataset res = (Dataset) context.getAttribute("res");
+    assertThat(res.getDataAsMap())
+        .contains(
+            Map.of("name", "A", "me_1", 0.12D, "me_2", 0L),
+            Map.of("name", "B", "me_1", 3.5D, "me_2", 1L),
+            Map.of("name", "C", "me_1", 10.7D, "me_2", 10L));
+
+    Map<String, Object> expectedNullRow = new HashMap<>();
+    expectedNullRow.put("name", "NullGuy");
+    expectedNullRow.put("me_1", null);
+    expectedNullRow.put("me_2", 100L);
+    assertThat(res.getDataAsMap()).contains(expectedNullRow);
+  }
 }

vtl-spark4/src/test/java/fr/insee/vtl/spark4/processing.engine/CalcTest.java

@@ -7,6 +7,7 @@
 import fr.insee.vtl.model.InMemoryDataset;
 import fr.insee.vtl.model.Structured;
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import javax.script.ScriptContext;
@@ -80,4 +81,40 @@ public void testCalcClause() throws ScriptException, InterruptedException {
             new Structured.Component("weight", Long.class, Dataset.Role.MEASURE),
             new Structured.Component("wisdom", Double.class, Dataset.Role.ATTRIBUTE));
   }
+
+  @Test
+  public void testCaseElseAppliesWhenWhenConditionIsNull() throws ScriptException {
+    ScriptContext context = engine.getContext();
+
+    Map<String, Object> r4 = new HashMap<>();
+    r4.put("name", "NullGuy");
+    r4.put("me_1", null);
+
+    InMemoryDataset dsWithNull =
+        new InMemoryDataset(
+            List.of(
+                Map.of("name", "A", "me_1", 0.12D),
+                Map.of("name", "B", "me_1", 3.5D),
+                Map.of("name", "C", "me_1", 10.7D),
+                r4),
+            Map.of("name", String.class, "me_1", Double.class),
+            Map.of("name", Dataset.Role.IDENTIFIER, "me_1", Dataset.Role.MEASURE));
+
+    context.setAttribute("ds_null", dsWithNull, ScriptContext.ENGINE_SCOPE);
+    engine.eval(
+        "res := ds_null[calc me_2 := case when me_1 <= 1 then 0 when me_1 > 1 and me_1 <= 10 then 1 when me_1 > 10 then 10 else 100];");
+
+    Dataset res = (Dataset) context.getAttribute("res");
+    assertThat(res.getDataAsMap())
+        .contains(
+            Map.of("name", "A", "me_1", 0.12D, "me_2", 0L),
+            Map.of("name", "B", "me_1", 3.5D, "me_2", 1L),
+            Map.of("name", "C", "me_1", 10.7D, "me_2", 10L));
+
+    Map<String, Object> expectedNullRow = new HashMap<>();
+    expectedNullRow.put("name", "NullGuy");
+    expectedNullRow.put("me_1", null);
+    expectedNullRow.put("me_2", 100L);
+    assertThat(res.getDataAsMap()).contains(expectedNullRow);
+  }
 }