NIFI-12704 Avoid NPE in escapeJson() for Root Path

This closes apache#8450 Signed-off-by: David Handermann <exceptionfactory@apache.org>
jrsteinebrey · Jun 17, 2024 · a52d6a8 · a52d6a8
1 parent bd1ad8f
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diff --git a/.../nifi-record-path/src/main/java/org/apache/nifi/record/path/paths/RecordPathCompiler.java b/.../nifi-record-path/src/main/java/org/apache/nifi/record/path/paths/RecordPathCompiler.java
@@ -130,6 +130,10 @@ public static RecordPathSegment buildPath(final Tree tree, final RecordPathSegme
                 return new RootPath();
             }
             case CHILD_REFERENCE: {
+                if (tree.getChildCount() == 0) {
+                    return new RootPath();
+                }
+
                 final Tree childTree = tree.getChild(0);
                 if (childTree == null) {
                     return new RootPath();

diff --git a/nifi-commons/nifi-record-path/src/test/java/org/apache/nifi/record/path/TestRecordPath.java b/nifi-commons/nifi-record-path/src/test/java/org/apache/nifi/record/path/TestRecordPath.java
@@ -2287,6 +2287,17 @@ public void testCountAsFilter() {
         assertEquals(48, fieldValues.get(0).getValue());
     }
 
+    @Test
+    public void testRecordRootReferenceInFunction() {
+        final Record record = createSimpleRecord();
+
+        final FieldValue singleArgumentFieldValue = evaluateSingleFieldValue("escapeJson(/)", record);
+        assertEquals("{\"id\":48,\"name\":\"John Doe\",\"missing\":null}", singleArgumentFieldValue.getValue());
+        final FieldValue multipleArgumentsFieldValue = evaluateSingleFieldValue("mapOf(\"copy\",/)", record);
+        assertInstanceOf(MapRecord.class, multipleArgumentsFieldValue.getValue());
+        assertEquals(record.toString(), ((MapRecord) multipleArgumentsFieldValue.getValue()).getValue("copy"));
+    }
+
     private List<RecordField> getDefaultFields() {
         final List<RecordField> fields = new ArrayList<>();
         fields.add(new RecordField("id", RecordFieldType.INT.getDataType()));
@@ -2339,4 +2350,11 @@ private Record createSimpleRecord() {
         return new MapRecord(schema, values);
     }
 
+    private static FieldValue evaluateSingleFieldValue(RecordPath recordPath, Record record) {
+        return recordPath.evaluate(record).getSelectedFields().findFirst().get();
+    }
+
+    private static FieldValue evaluateSingleFieldValue(String path, Record record) {
+        return evaluateSingleFieldValue(RecordPath.compile(path), record);
+    }
 }