refactor: eth address tech debt cleanup (AztecProtocol#4442)

We used to serialize EthAddress as 32 bytes because we needed that for
compatibility with CBINDs. Given that we no longer use the C++ code this
is no longer necessary.

**Note**: decided to not completely nuke `EthAddress.toBuffer32()`
because that would require updating how we compute calldata/body hash
and it makes sense to do that once we'll do that in AztecProtocol#3938 (linked it in
the issue).

yarn-project/circuit-types/src/contract_data.ts

@@ -260,7 +260,7 @@ export class ContractData {
    * @returns Encoded buffer.
    */
   public toBuffer(): Buffer {
-    return serializeToBuffer(this.contractAddress, this.portalContractAddress.toBuffer20());
+    return serializeToBuffer(this.contractAddress, this.portalContractAddress);
   }
 
   /**

yarn-project/circuit-types/src/l1_to_l2_message.ts

@@ -187,7 +187,7 @@ export class L1Actor {
 
   static fromBuffer(buffer: Buffer | BufferReader): L1Actor {
     const reader = BufferReader.asReader(buffer);
-    const ethAddr = new EthAddress(reader.readBytes(32));
+    const ethAddr = reader.readObject(EthAddress);
     const chainId = reader.readNumber();
     return new L1Actor(ethAddr, chainId);
   }

yarn-project/circuit-types/src/l2_block.ts

@@ -573,6 +573,7 @@ export class L2Block {
         newL2ToL1MsgsBuffer,
         this.newContracts[i].toBuffer(),
         this.newContractData[i].contractAddress.toBuffer(),
+        // TODO(#3938): make portal address 20 bytes here when updating the hashing
         this.newContractData[i].portalContractAddress.toBuffer32(),
         encryptedLogsHashKernel0,
         unencryptedLogsHashKernel0,

yarn-project/circuits.js/src/abis/abis.test.ts

@@ -2,6 +2,7 @@ import { times } from '@aztec/foundation/collection';
 
 import {
   AztecAddress,
+  EthAddress,
   Fr,
   FunctionData,
   FunctionLeafPreimage,
@@ -143,7 +144,7 @@ describe('abis', () => {
   });
 
   it('computes zero contract leaf', () => {
-    const cd = new NewContractData(AztecAddress.ZERO, AztecAddress.ZERO, new Fr(0n));
+    const cd = new NewContractData(AztecAddress.ZERO, EthAddress.ZERO, new Fr(0n));
     const res = computeContractLeaf(cd);
     expect(res).toMatchSnapshot();
   });

yarn-project/circuits.js/src/structs/call_context.ts

@@ -7,13 +7,8 @@ import { FieldsOf } from '@aztec/foundation/types';
 
 /**
  * Call context.
- * @see abis/call_context.hpp
  */
 export class CallContext {
-  /**
-   * Address of the portal contract to the storage contract.
-   */
-  public portalContractAddress: EthAddress;
   constructor(
     /**
      * Address of the account which represents the entity who invoked the call.
@@ -27,9 +22,8 @@ export class CallContext {
     public storageContractAddress: AztecAddress,
     /**
      * Address of the portal contract to the storage contract.
-     * Union type is a kludge until C++ has an eth address type.
      */
-    portalContractAddress: EthAddress | Fr,
+    public portalContractAddress: EthAddress,
     /**
      * Function selector of the function being called.
      */
@@ -50,10 +44,7 @@ export class CallContext {
      * The start side effect counter for this call context.
      */
     public startSideEffectCounter: number,
-  ) {
-    this.portalContractAddress =
-      portalContractAddress instanceof EthAddress ? portalContractAddress : EthAddress.fromField(portalContractAddress);
-  }
+  ) {}
 
   /**
    * Returns a new instance of CallContext with zero msg sender, storage contract address and portal contract address.
@@ -63,7 +54,7 @@ export class CallContext {
     return new CallContext(
       AztecAddress.ZERO,
       AztecAddress.ZERO,
-      Fr.ZERO,
+      EthAddress.ZERO,
       FunctionSelector.empty(),
       false,
       false,
@@ -119,10 +110,10 @@ export class CallContext {
   static fromBuffer(buffer: Buffer | BufferReader) {
     const reader = BufferReader.asReader(buffer);
     return new CallContext(
-      new AztecAddress(reader.readBytes(32)),
-      new AztecAddress(reader.readBytes(32)),
-      new EthAddress(reader.readBytes(32)),
-      FunctionSelector.fromBuffer(reader.readBytes(4)),
+      reader.readObject(AztecAddress),
+      reader.readObject(AztecAddress),
+      reader.readObject(EthAddress),
+      reader.readObject(FunctionSelector),
       reader.readBoolean(),
       reader.readBoolean(),
       reader.readBoolean(),
@@ -135,7 +126,7 @@ export class CallContext {
     return new CallContext(
       reader.readObject(AztecAddress),
       reader.readObject(AztecAddress),
-      reader.readField(),
+      reader.readObject(EthAddress),
       reader.readObject(FunctionSelector),
       reader.readBoolean(),
       reader.readBoolean(),

yarn-project/circuits.js/src/structs/contract_deployment_data.ts

@@ -70,18 +70,18 @@ export class ContractDeploymentData {
       Fr.fromBuffer(reader),
       Fr.fromBuffer(reader),
       Fr.fromBuffer(reader),
-      new EthAddress(reader.readBytes(32)),
+      reader.readObject(EthAddress),
     );
   }
 
   static fromFields(fields: Fr[] | FieldReader): ContractDeploymentData {
     const reader = FieldReader.asReader(fields);
 
-    const publicKey = Point.fromFields(reader);
+    const publicKey = reader.readObject(Point);
     const initializationHash = reader.readField();
     const contractClassId = reader.readField();
     const contractAddressSalt = reader.readField();
-    const portalContractAddress = new EthAddress(reader.readField().toBuffer());
+    const portalContractAddress = reader.readObject(EthAddress);
 
     return new ContractDeploymentData(
       publicKey,

yarn-project/circuits.js/src/structs/kernel/combined_accumulated_data.ts

@@ -33,29 +33,20 @@ import { SideEffect, SideEffectLinkedToNoteHash } from '../side_effects.js';
  * Note: Not to be confused with `ContractDeploymentData`.
  */
 export class NewContractData {
-  /**
-   * Ethereum address of the portal contract on L1.
-   */
-  public portalContractAddress: EthAddress;
   constructor(
     /**
      * Aztec address of the contract.
      */
     public contractAddress: AztecAddress,
     /**
      * Ethereum address of the portal contract on L1.
-     * TODO(AD): refactor this later
-     * currently there is a kludge with circuits cpp as it emits an AztecAddress
      */
-    portalContractAddress: EthAddress | AztecAddress,
+    public portalContractAddress: EthAddress,
     /**
      * Contract class id.
      */
     public contractClassId: Fr,
-  ) {
-    // Handle circuits emitting this as an AztecAddress
-    this.portalContractAddress = new EthAddress(portalContractAddress.toBuffer());
-  }
+  ) {}
 
   toBuffer() {
     return serializeToBuffer(this.contractAddress, this.portalContractAddress, this.contractClassId);
@@ -68,11 +59,7 @@ export class NewContractData {
    */
   static fromBuffer(buffer: Buffer | BufferReader): NewContractData {
     const reader = BufferReader.asReader(buffer);
-    return new NewContractData(
-      reader.readObject(AztecAddress),
-      new EthAddress(reader.readBytes(32)),
-      Fr.fromBuffer(reader),
-    );
+    return new NewContractData(reader.readObject(AztecAddress), reader.readObject(EthAddress), Fr.fromBuffer(reader));
   }
 
   static empty() {
@@ -157,7 +144,7 @@ export class OptionallyRevealedData {
       Fr.fromBuffer(reader),
       reader.readObject(FunctionData),
       Fr.fromBuffer(reader),
-      new EthAddress(reader.readBytes(32)),
+      reader.readObject(EthAddress),
       reader.readBoolean(),
       reader.readBoolean(),
       reader.readBoolean(),

yarn-project/circuits.js/src/structs/kernel/private_kernel.test.ts

@@ -1,18 +1,17 @@
+// TODO(#4411): this is mostly redundant. Nuke this
 import {
   makeCallRequest,
   makeFinalAccumulatedData,
   makeNewSideEffect,
   makePreviousKernelData,
   makePrivateCallData,
-  makePrivateCircuitPublicInputs,
   makePrivateKernelInputsInner,
   makePrivateKernelPublicInputsFinal,
 } from '../../tests/factories.js';
 import {
   CallRequest,
   FinalAccumulatedData,
   PreviousKernelData,
-  PrivateCircuitPublicInputs,
   PrivateKernelPublicInputsFinal,
   SideEffect,
 } from '../index.js';
@@ -74,11 +73,3 @@ describe('CallRequest', () => {
     expect(CallRequest.fromBuffer(buf)).toEqual(fad);
   });
 });
-
-describe('Private Circuit Public Inputs', () => {
-  it('convert to and from buffer', () => {
-    const pkpi = makePrivateCircuitPublicInputs();
-    const buf = pkpi.toBuffer();
-    expect(PrivateCircuitPublicInputs.fromBuffer(buf)).toEqual(pkpi);
-  });
-});

yarn-project/foundation/src/eth-address/eth_address.test.ts

@@ -8,7 +8,7 @@ describe('address', () => {
 
   it('should return correct buffer', () => {
     const address = EthAddress.fromString('0xc6d9d2cd449a754c494264e1809c50e34d64562b');
-    expect(address.toBuffer20()).toEqual(Buffer.from('c6d9d2cD449A754c494264e1809c50e34D64562b', 'hex'));
+    expect(address.toBuffer()).toEqual(Buffer.from('c6d9d2cD449A754c494264e1809c50e34D64562b', 'hex'));
   });
 
   it('should return correct 32 byte buffer', () => {
@@ -18,16 +18,6 @@ describe('address', () => {
     );
   });
 
-  it('should create address from 32 byte buffer', () => {
-    const buffer = Buffer.from('000000000000000000000000c6d9d2cD449A754c494264e1809c50e34D64562b', 'hex');
-    expect(new EthAddress(buffer)).toEqual(EthAddress.fromString('0xc6d9d2cD449A754c494264e1809c50e34D64562b'));
-  });
-
-  it('should not create address from 32 byte buffer that does not start with 12 0 bytes', () => {
-    const buffer = Buffer.from('010000000000000000000000c6d9d2cD449A754c494264e1809c50e34D64562b', 'hex');
-    expect(() => new EthAddress(buffer)).toThrowError();
-  });
-
   it('should have correct zero address', () => {
     expect(EthAddress.ZERO.toString()).toBe('0x0000000000000000000000000000000000000000');
   });

yarn-project/foundation/src/eth-address/index.ts

@@ -1,7 +1,7 @@
 import { keccak256String } from '../crypto/keccak/index.js';
 import { randomBytes } from '../crypto/random/index.js';
 import { Fr } from '../fields/index.js';
-import { BufferReader } from '../serialize/index.js';
+import { BufferReader, FieldReader } from '../serialize/index.js';
 
 /**
  * Represents an Ethereum address as a 20-byte buffer and provides various utility methods
@@ -20,13 +20,7 @@ export class EthAddress {
   public static ZERO = new EthAddress(Buffer.alloc(EthAddress.SIZE_IN_BYTES));
 
   constructor(private buffer: Buffer) {
-    if (buffer.length === 32) {
-      if (!buffer.slice(0, 12).equals(Buffer.alloc(12))) {
-        throw new Error(`Invalid address buffer: ${buffer.toString('hex')}`);
-      } else {
-        this.buffer = buffer.slice(12);
-      }
-    } else if (buffer.length !== EthAddress.SIZE_IN_BYTES) {
+    if (buffer.length !== EthAddress.SIZE_IN_BYTES) {
       throw new Error(`Expect buffer size to be ${EthAddress.SIZE_IN_BYTES}. Got ${buffer.length}.`);
     }
   }
@@ -176,21 +170,10 @@ export class EthAddress {
   }
 
   /**
-   * Alias for toBuffer32.
-   * @returns A 32-byte Buffer containing the padded Ethereum address.
+   * Returns a 20-byte buffer representation of the Ethereum address.
+   * @returns A 20-byte Buffer containing the Ethereum address.
    */
   public toBuffer() {
-    return this.toBuffer32();
-  }
-
-  /**
-   * Returns the internal Buffer representation of the Ethereum address.
-   * This method is useful when working with raw binary data or when
-   * integrating with other modules that require a Buffer as input.
-   *
-   * @returns A Buffer instance containing the 20-byte Ethereum address.
-   */
-  public toBuffer20() {
     return this.buffer;
   }
 
@@ -201,6 +184,7 @@ export class EthAddress {
    *
    * @returns A 32-byte Buffer containing the padded Ethereum address.
    */
+  // TODO(#3938): nuke this
   public toBuffer32() {
     const buffer = Buffer.alloc(32);
     this.buffer.copy(buffer, 12);
@@ -225,14 +209,19 @@ export class EthAddress {
     return new EthAddress(fr.toBuffer().slice(-EthAddress.SIZE_IN_BYTES));
   }
 
+  static fromFields(fields: Fr[] | FieldReader) {
+    const reader = FieldReader.asReader(fields);
+    return EthAddress.fromField(reader.readField());
+  }
+
   /**
    * Deserializes from a buffer or reader, corresponding to a write in cpp.
    * @param buffer - Buffer to read from.
    * @returns The EthAddress.
    */
   static fromBuffer(buffer: Buffer | BufferReader): EthAddress {
     const reader = BufferReader.asReader(buffer);
-    return new EthAddress(reader.readBytes(32));
+    return new EthAddress(reader.readBytes(EthAddress.SIZE_IN_BYTES));
   }
 
   /**

yarn-project/foundation/src/serialize/serialize.ts

@@ -105,12 +105,6 @@ export type Bufferable =
   | Buffer
   | number
   | string
-  | {
-      /**
-       * Serialize to a buffer of 32 bytes.
-       */
-      toBuffer32: () => Buffer;
-    }
   | {
       /**
        * Serialize to a buffer.
@@ -135,27 +129,6 @@ export type Fieldeable =
     }
   | Fieldeable[];
 
-/**
- * Checks whether an object implements the toBuffer32 method.
- * @param obj - The object to check.
- * @returns Whether the object implements the toBuffer32 method.
- */
-function isSerializableToBuffer32(obj: object): obj is {
-  /**
-   * Signature of the target serialization function.
-   */
-  toBuffer32: () => Buffer;
-} {
-  return !!(
-    obj as {
-      /**
-       * Signature of the target serialization function.
-       */
-      toBuffer32: () => Buffer;
-    }
-  ).toBuffer32;
-}
-
 /**
  * Serializes a list of objects contiguously.
  * @param objs - Objects to serialize.
@@ -176,8 +149,6 @@ export function serializeToBufferArray(...objs: Bufferable[]): Buffer[] {
     } else if (typeof obj === 'string') {
       ret.push(numToUInt32BE(obj.length));
       ret.push(Buffer.from(obj));
-    } else if (isSerializableToBuffer32(obj)) {
-      ret.push(obj.toBuffer32());
     } else {
       ret.push(obj.toBuffer());
     }