Fix exception when sibling array is null

Author: bblanchon

src/assistant/parsingProgram.js

@@ -46,7 +46,7 @@ function extractValue(prg, cfg) {
             value: value[i],
             parent: elementExpression,
             name: makeVariableName(elementExpression),
-            siblings: cfg.siblings?.map((x) => x[i]),
+            siblings: cfg.siblings?.map((x) => (x ? x[i] : null)),
           });
         }
       }

src/assistant/parsingProgram.spec.js

@@ -410,4 +410,17 @@ describe("writeDecompositionCode", function () {
         "}\n"
     );
   });
+
+  it("null sibling array", () => {
+    testDescompositionCode(
+      [{ data: [1, 3] }, { data: [2, 4] }, { data: null }],
+      `for (JsonObject item : doc.as<JsonArray>()) {
+
+  int data_0 = item["data"][0]; // 1, 2, 0
+  int data_1 = item["data"][1]; // 3, 4, 0
+
+}
+`
+    );
+  });
 });