fix(parsers.xpath): Handle explicitly defined fields correctly (#13550)

plugins/parsers/xpath/parser.go

@@ -397,6 +397,13 @@ func (p *Parser) parseQuery(starttime time.Time, doc, selected dataNode, config
 		if err != nil {
 			return nil, fmt.Errorf("failed to query field %q: %w", name, err)
 		}
+
+		if config.FieldsHexFilter != nil && config.FieldsHexFilter.Match(name) {
+			if b, ok := v.([]byte); ok {
+				v = hex.EncodeToString(b)
+			}
+		}
+
 		fields[name] = v
 	}
 

plugins/parsers/xpath/testcases/cbor_hex_encoding_explicit/expected.out

@@ -0,0 +1 @@
+data fieldc="this is a test",fielda="0001020304050607",fieldb="666f6f626172" 1687852514000000000

plugins/parsers/xpath/testcases/cbor_hex_encoding_explicit/telegraf.conf

@@ -0,0 +1,29 @@
+# Example data:
+# [
+#   {
+#     "str_a": bytearray("this is a test"),
+#     "str_b": bytearray("foobar"),
+#     "bytes_a": bytearray([0, 1, 2, 3, 4, 5, 6, 7]),
+#     "bytes_b": bytearray("foobar"),
+#     "timestamp": 1687852514
+#   }
+# ]
+
+[[inputs.file]]
+  files = ["./testcases/cbor_hex_encoding/data.bin"]
+  data_format = "xpath_cbor"
+
+  xpath_native_types = true
+
+  [[inputs.file.xpath]]
+    metric_name = "'data'"
+    metric_selection = "child::*"
+    timestamp = "timestamp"
+    timestamp_format = "unix"
+    fields_bytes_as_hex = ["fielda", "fieldb"]
+
+    [inputs.file.xpath.fields]
+      fielda = "bytes_a"
+      fieldb = "bytes_b"
+      fieldc = "str_a"
+