Commiting Unit Test with Failing Byte Array Deserialization

avro/README.md

@@ -748,6 +748,50 @@ registered and used!
 
 <!-- cargo-rdme end -->
 
+
+### Deserializing Avro Byte Arrays
+
+if using the Serde way to deserialize avro files, there are sometimes special derive statements that need to be applied in the case of byte arrays.
+
+Here is an example of deserializing an avro file containing a nullable byte array. 
+
+
+```rust
+use apache_avro::{from_value, Reader};
+use serde::{Serialize,Deserialize};
+use std::fs::File;
+use std::io::BufReader;
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+struct ExampleByteArray{
+
+    #[serde(with = "apache_avro::serde_avro_bytes_opt")]
+    data_bytes: Option<Vec<u8>>,
+    description: Option<String>
+}
+
+fn deserialize_byte_array(){
+
+    // Load the example file into reader
+    let file = File::open("somefile.avro".to_string()).unwrap();
+    let reader = BufReader::new(file);
+    let avro_reader = Reader::new(reader).unwrap();
+
+
+    // Deserialize into struct with byte array field
+    for value in avro_reader{
+        let value = value.unwrap();
+        let deserialized = from_value::<ExampleByteArray>(&value).unwrap();
+        println!("{:?}", deserialized);
+    }
+
+}
+```
+
+Full implementation and other options for things like fixed byte arrays can found in src/bytes.rs
+
+
+
 ## License
 
 This project is licensed under [Apache License 2.0](https://github.com/apache/avro/blob/main/LICENSE.txt).

avro/tests/avro-rs-285-bytes_deserialization.rs

@@ -0,0 +1,76 @@
+use apache_avro::{from_value, Reader};
+use serde::{Serialize,Deserialize};
+use std::fs::File;
+use std::io::BufReader;
+
+
+//UPDATE: For byte deserialization to work, you need to add the serde attribute #[serde(with = "apache_avro::serde_avro_bytes_opt")] in this case. There are a lot of other options as well documented in bytes.rs
+
+
+// This is the schema that was used to write
+// schema = {
+//     "type": "record",
+//     "name": "SimpleRecord",
+//     "fields": [
+//         {"name": "data_bytes", "type": ["null", "bytes"], "default": None},
+//         {"name": "description", "type": ["null", "string"], "default": None}
+//     ]
+// }
+
+
+// Here is an example struct that matches the schema, and another with filtered out byte array field
+// The reason this is very useful is that in extremely large deeply nested avro files, structs mapped to grab fields of interest in deserialization
+// is really effecient and effective. The issue is that when I'm trying to deserialize a byte array field I get the error below no matter how I approach.
+// Bytes enum under value doesn't implement Deserialize in that way so I can't just make it a Value::Bytes
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+
+struct ExampleByteArray{
+
+
+    //update I have discovered that this is the fix
+    #[serde(with = "apache_avro::serde_avro_bytes_opt")]
+    data_bytes: Option<Vec<u8>>,
+    description: Option<String>
+}
+
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+struct ExampleByteArrayFiltered{
+    description: Option<String>
+}
+
+#[test]
+fn avro_rs_285_bytes_deserialization_failure(){
+
+    // Load the example file into reader
+    let file = File::open("./tests/avro-rs-285-bytes_deserialization.avro".to_string()).unwrap();
+    let reader = BufReader::new(file);
+    let avro_reader = Reader::new(reader).unwrap();
+
+
+    // attempt to deserialize into struct with byte array field
+    for value in avro_reader{
+        let value = value.unwrap();
+        let deserialized = from_value::<ExampleByteArray>(&value).unwrap();
+        println!("{:?}", deserialized);
+    }
+
+}
+
+#[test]
+fn avro_rs_285_bytes_deserialization_pass_when_filtered(){
+
+    // Load the example file into reader
+    let file = File::open("./tests/avro-rs-285-bytes_deserialization.avro".to_string()).unwrap();
+    let reader = BufReader::new(file);
+    let avro_reader = Reader::new(reader).unwrap();
+
+    // attempt to deserialize into struct with byte array field filtered out, this will be successful
+    for value in avro_reader{
+        let value = value.unwrap();
+        let deserialized = from_value::<ExampleByteArrayFiltered>(&value).unwrap();
+        println!("{:?}", deserialized);
+    }
+
+}