fix(rbc): throw error instead of throwing away unknown fields

packages/ripple-binary-codec/HISTORY.md

@@ -3,7 +3,8 @@
 ## Unreleased
 
 ### Fixed
-- add `MPTAmount` support in `Issue` (rippled internal type)
+* add `MPTCurrency` support in `Issue` (rippled internal type)
+* Throw an error during serialization if a field is unknown, rather than silently throwing it away.
 
 ## 2.3.0 (2025-2-13)
 

packages/ripple-binary-codec/src/types/st-object.ts

@@ -116,14 +116,25 @@ class STObject extends SerializedType {
       return Object.assign(acc, handled ?? { [key]: val })
     }, {})
 
-    let sorted = Object.keys(xAddressDecoded)
-      .map((f: string): FieldInstance => definitions.field[f] as FieldInstance)
-      .filter(
-        (f: FieldInstance): boolean =>
-          f !== undefined &&
-          xAddressDecoded[f.name] !== undefined &&
-          f.isSerialized,
+    function isValidFieldInstance(
+      f: FieldInstance | undefined,
+    ): f is FieldInstance {
+      return (
+        f !== undefined &&
+        xAddressDecoded[f.name] !== undefined &&
+        f.isSerialized
       )
+    }
+
+    let sorted = Object.keys(xAddressDecoded)
+      .map((f: string): FieldInstance | undefined => {
+        if (!(f in definitions.field)) {
+          if (f[0] === f[0].toLowerCase()) return undefined
+          throw new Error(`Field ${f} is not defined in the definitions`)
+        }
+        return definitions.field[f] as FieldInstance
+      })
+      .filter(isValidFieldInstance)
       .sort((a, b) => {
         return a.ordinal - b.ordinal
       })

packages/ripple-binary-codec/test/definitions.test.ts

@@ -34,8 +34,8 @@ describe('encode and decode using new types as a parameter', function () {
   it('can encode and decode a new Field', function () {
     const tx = { ...txJson, NewFieldDefinition: 10 }
 
-    // Before updating the types, undefined fields will be ignored on encode
-    expect(decode(encode(tx))).not.toEqual(tx)
+    // Before updating the types, undefined fields will throw an error
+    expect(() => encode(tx)).toThrow()
 
     // Normally this would be generated directly from rippled with something like `server_definitions`.
     // Added here to make it easier to see what is actually changing in the definitions.json file.
@@ -72,8 +72,8 @@ describe('encode and decode using new types as a parameter', function () {
       ],
     }
 
-    // Before updating the types, undefined fields will be ignored on encode
-    expect(decode(encode(tx))).not.toEqual(tx)
+    // Before updating the types, undefined fields will throw an error
+    expect(() => encode(tx)).toThrow()
 
     // Normally this would be generated directly from rippled with something like `server_definitions`.
     // Added here to make it easier to see what is actually changing in the definitions.json file.
@@ -141,8 +141,8 @@ describe('encode and decode using new types as a parameter', function () {
       },
     ])
 
-    // Test that before updating the types this tx fails to decode correctly. Note that undefined fields are ignored on encode.
-    expect(decode(encode(tx))).not.toEqual(tx)
+    // Test that before updating the types this tx fails to decode correctly. Note that undefined fields will throw an error.
+    expect(() => encode(tx)).toThrow()
 
     class NewType extends UInt32 {
       // Should be the same as UInt32

packages/ripple-binary-codec/test/tx-encode-decode.test.ts

@@ -116,4 +116,13 @@ describe('encoding and decoding tx_json', function () {
       encode(my_tx)
     }).toThrow()
   })
+
+  it('throws when there is an unknown field', function () {
+    const my_tx = Object.assign({}, tx_json, {
+      BadField: 1,
+    })
+    expect(() => {
+      encode(my_tx)
+    }).toThrow()
+  })
 })