RUST-426 Fix Decimal128 human-readable serialization (#479)

Author: abr-egn

src/de/raw.rs

@@ -17,7 +17,6 @@ use crate::{
     serde_helpers::HUMAN_READABLE_NEWTYPE,
     spec::{BinarySubtype, ElementType},
     uuid::UUID_NEWTYPE_NAME,
-    Bson,
     DateTime,
     Decimal128,
     DeserializerOptions,
@@ -292,9 +291,8 @@ impl<'de> Deserializer<'de> {
                     )),
                     _ => {
                         let code = read_string(&mut self.bytes, utf8_lossy)?;
-                        let doc = Bson::JavaScriptCode(code).into_extended_document(false);
                         visitor.visit_map(MapDeserializer::new(
-                            doc,
+                            doc! { "$code": code },
                             #[allow(deprecated)]
                             DeserializerOptions::builder().human_readable(false).build(),
                         ))
@@ -350,9 +348,8 @@ impl<'de> Deserializer<'de> {
                     )),
                     _ => {
                         let symbol = read_string(&mut self.bytes, utf8_lossy)?;
-                        let doc = Bson::Symbol(symbol).into_extended_document(false);
                         visitor.visit_map(MapDeserializer::new(
-                            doc,
+                            doc! { "$symbol": symbol },
                             #[allow(deprecated)]
                             DeserializerOptions::builder().human_readable(false).build(),
                         ))

src/decimal128.rs

@@ -48,7 +48,7 @@ impl Decimal128 {
 
 impl fmt::Debug for Decimal128 {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Decimal128(...)")
+        write!(f, "Decimal128({})", hex::encode(self.bytes))
     }
 }
 

src/ser/serde.rs

@@ -10,7 +10,6 @@ use serde::ser::{
     SerializeTupleStruct,
     SerializeTupleVariant,
 };
-use serde_bytes::Bytes;
 
 use crate::{
     bson::{Array, Bson, DbPointer, Document, JavaScriptCodeWithScope, Regex, Timestamp},
@@ -85,11 +84,7 @@ impl Serialize for Bson {
             }
             Bson::RegularExpression(re) => re.serialize(serializer),
             Bson::Timestamp(t) => t.serialize(serializer),
-            Bson::Decimal128(d) => {
-                let mut state = serializer.serialize_struct("$numberDecimal", 1)?;
-                state.serialize_field("$numberDecimalBytes", Bytes::new(&d.bytes))?;
-                state.end()
-            }
+            Bson::Decimal128(d) => d.serialize(serializer),
             Bson::Undefined => {
                 let mut state = serializer.serialize_struct("$undefined", 1)?;
                 state.serialize_field("$undefined", &true)?;
@@ -705,15 +700,14 @@ impl Serialize for Decimal128 {
     where
         S: ser::Serializer,
     {
-        if serializer.is_human_readable() {
-            let mut state = serializer.serialize_map(Some(1))?;
-            state.serialize_entry("$numberDecimal", &self.to_string())?;
-            state.end()
+        let human_readable = serializer.is_human_readable();
+        let mut state = serializer.serialize_struct("$numberDecimal", 1)?;
+        if human_readable {
+            state.serialize_field("$numberDecimal", &self.to_string())?;
         } else {
-            let mut state = serializer.serialize_struct("$numberDecimal", 1)?;
             state.serialize_field("$numberDecimalBytes", serde_bytes::Bytes::new(&self.bytes))?;
-            state.end()
         }
+        state.end()
     }
 }
 

src/tests/spec/corpus.rs

@@ -267,12 +267,15 @@ fn run_test(test: TestFile) {
             description,
         );
 
-        assert_eq!(
-            hex::encode(documenttowriter_todocument_documentfromreader_cb).to_lowercase(),
-            valid.canonical_bson.to_lowercase(),
-            "{}",
-            description,
-        );
+        // bson::to_document(&Document) may be lossy due to round-tripping extjson
+        if valid.lossy != Some(true) {
+            assert_eq!(
+                hex::encode(documenttowriter_todocument_documentfromreader_cb).to_lowercase(),
+                valid.canonical_bson.to_lowercase(),
+                "{}",
+                description,
+            );
+        }
 
         assert_eq!(
             hex::encode(tovec_documentfromreader_cb).to_lowercase(),
@@ -313,11 +316,14 @@ fn run_test(test: TestFile) {
                 description
             );
 
-            assert_eq!(
-                documentfromreader_cb, todocument_documentfromreader_cb,
-                "{}",
-                description
-            );
+            // bson::to_document(&Document) may be lossy due to round-tripping extjson
+            if valid.lossy != Some(true) {
+                assert_eq!(
+                    documentfromreader_cb, todocument_documentfromreader_cb,
+                    "{}",
+                    description
+                );
+            }
 
             assert_eq!(
                 document_from_raw_document, documentfromreader_cb,