feat(cli): Inspect contract command (#2248)

Adds an `inspect-contract` command that lists the functions available to
call. Omits internal functions and stev.

```
$ yarn aztec-cli inspect-contract PrivateTokenContractAbi
secret constructor(initial_supply: Field, owner: Field)
unconstrained getBalance(owner: Field)
secret mint(amount: Field, owner: Field)
secret transfer(amount: Field, recipient: Field)
```

Fixes #2180

yarn-project/cli/src/index.ts

@@ -9,7 +9,7 @@ import {
   getSchnorrAccount,
   isContractDeployed,
 } from '@aztec/aztec.js';
-import { StructType } from '@aztec/foundation/abi';
+import { StructType, decodeFunctionSignatureWithParameterNames } from '@aztec/foundation/abi';
 import { JsonStringify } from '@aztec/foundation/json-rpc';
 import { DebugLogger, LogFn } from '@aztec/foundation/log';
 import { fileURLToPath } from '@aztec/foundation/url';
@@ -485,6 +485,27 @@ export function getProgram(log: LogFn, debugLogger: DebugLogger): Command {
       Object.entries(info).map(([key, value]) => log(`${startCase(key)}: ${value}`));
     });
 
+  program
+    .command('inspect-contract')
+    .description('Shows list of external callable functions for a contract')
+    .argument(
+      '<contractAbiFile>',
+      `A compiled Noir contract's ABI in JSON format or name of a contract ABI exported by @aztec/noir-contracts`,
+    )
+    .action(async (contractAbiFile: string) => {
+      const contractAbi = await getContractAbi(contractAbiFile, debugLogger);
+      const contractFns = contractAbi.functions.filter(
+        f => !f.isInternal && f.name !== 'compute_note_hash_and_nullifier',
+      );
+      if (contractFns.length === 0) {
+        log(`No external functions found for contract ${contractAbi.name}`);
+      }
+      for (const fn of contractFns) {
+        const signature = decodeFunctionSignatureWithParameterNames(fn.name, fn.parameters);
+        log(`${fn.functionType} ${signature}`);
+      }
+    });
+
   compileContract(program, 'compile', log);
   generateTypescriptInterface(program, 'generate-typescript', log);
   generateNoirInterface(program, 'generate-noir-interface', log);

yarn-project/foundation/src/abi/decoder.test.ts

@@ -0,0 +1,77 @@
+import { FunctionAbi } from './abi.js';
+import { decodeFunctionSignature, decodeFunctionSignatureWithParameterNames } from './decoder.js';
+
+describe('abi/decoder', () => {
+  // Copied from yarn-project/noir-contracts/src/contracts/test_contract/target/Test.json
+  const abi = {
+    name: 'testCodeGen',
+    parameters: [
+      { name: 'aField', type: { kind: 'field' }, visibility: 'private' },
+      { name: 'aBool', type: { kind: 'boolean' }, visibility: 'private' },
+      { name: 'aNumber', type: { kind: 'integer', sign: 'unsigned', width: 32 }, visibility: 'private' },
+      { name: 'anArray', type: { kind: 'array', length: 2, type: { kind: 'field' } }, visibility: 'private' },
+      {
+        name: 'aStruct',
+        type: {
+          kind: 'struct',
+          path: 'Test::DummyNote',
+          fields: [
+            { name: 'amount', type: { kind: 'field' } },
+            { name: 'secretHash', type: { kind: 'field' } },
+          ],
+        },
+        visibility: 'private',
+      },
+      {
+        name: 'aDeepStruct',
+        type: {
+          kind: 'struct',
+          path: 'Test::DeepStruct',
+          fields: [
+            { name: 'aField', type: { kind: 'field' } },
+            { name: 'aBool', type: { kind: 'boolean' } },
+            {
+              name: 'aNote',
+              type: {
+                kind: 'struct',
+                path: 'Test::DummyNote',
+                fields: [
+                  { name: 'amount', type: { kind: 'field' } },
+                  { name: 'secretHash', type: { kind: 'field' } },
+                ],
+              },
+            },
+            {
+              name: 'manyNotes',
+              type: {
+                kind: 'array',
+                length: 3,
+                type: {
+                  kind: 'struct',
+                  path: 'Test::DummyNote',
+                  fields: [
+                    { name: 'amount', type: { kind: 'field' } },
+                    { name: 'secretHash', type: { kind: 'field' } },
+                  ],
+                },
+              },
+            },
+          ],
+        },
+        visibility: 'private',
+      },
+    ],
+  } as unknown as Pick<FunctionAbi, 'name' | 'parameters'>;
+
+  it('decodes function signature', () => {
+    expect(decodeFunctionSignature(abi.name, abi.parameters)).toMatchInlineSnapshot(
+      `"testCodeGen(Field,bool,u32,[Field;2],(Field,Field),(Field,bool,(Field,Field),[(Field,Field);3]))"`,
+    );
+  });
+
+  it('decodes function signature with parameter names', () => {
+    expect(decodeFunctionSignatureWithParameterNames(abi.name, abi.parameters)).toMatchInlineSnapshot(
+      `"testCodeGen(aField: Field, aBool: bool, aNumber: u32, anArray: [Field;2], aStruct: (amount: Field, secretHash: Field), aDeepStruct: (aField: Field, aBool: bool, aNote: (amount: Field, secretHash: Field), manyNotes: [(amount: Field, secretHash: Field);3]))"`,
+    );
+  });
+});

yarn-project/foundation/src/abi/decoder.ts

@@ -1,4 +1,4 @@
-import { ABIParameter, ABIType, FunctionAbi } from '@aztec/foundation/abi';
+import { ABIParameter, ABIType, ABIVariable, FunctionAbi } from '@aztec/foundation/abi';
 import { Fr } from '@aztec/foundation/fields';
 
 /**
@@ -91,14 +91,17 @@ export function decodeReturnValues(abi: FunctionAbi, returnValues: Fr[]) {
  * Decodes the signature of a function from the name and parameters.
  */
 export class FunctionSignatureDecoder {
-  constructor(private name: string, private parameters: ABIParameter[]) {}
+  private separator: string;
+  constructor(private name: string, private parameters: ABIParameter[], private includeNames = false) {
+    this.separator = includeNames ? ', ' : ',';
+  }
 
   /**
-   * Decodes a single function parameter for the function signature.
-   * @param param - The parameter to decode.
+   * Decodes a single function parameter type for the function signature.
+   * @param param - The parameter type to decode.
    * @returns A string representing the parameter type.
    */
-  private decodeParameter(param: ABIType): string {
+  private getParameterType(param: ABIType): string {
     switch (param.kind) {
       case 'field':
         return 'Field';
@@ -110,29 +113,49 @@ export class FunctionSignatureDecoder {
       case 'boolean':
         return 'bool';
       case 'array':
-        return `[${this.decodeParameter(param.type)};${param.length}]`;
+        return `[${this.getParameterType(param.type)};${param.length}]`;
       case 'struct':
-        return `(${param.fields.map(field => `${this.decodeParameter(field.type)}`).join(',')})`;
+        return `(${param.fields.map(field => `${this.decodeParameter(field)}`).join(this.separator)})`;
       default:
         throw new Error(`Unsupported type: ${param.kind}`);
     }
   }
 
+  /**
+   * Decodes a single function parameter for the function signature.
+   * @param param - The parameter to decode.
+   * @returns A string representing the parameter type and optionally its name.
+   */
+  private decodeParameter(param: ABIVariable): string {
+    const type = this.getParameterType(param.type);
+    return this.includeNames ? `${param.name}: ${type}` : type;
+  }
+
   /**
    * Decodes all the parameters and build the function signature
    * @returns The function signature.
    */
   public decode(): string {
-    return `${this.name}(${this.parameters.map(param => this.decodeParameter(param.type)).join(',')})`;
+    return `${this.name}(${this.parameters.map(param => this.decodeParameter(param)).join(this.separator)})`;
   }
 }
 
 /**
  * Decodes a function signature from the name and parameters.
- * @param name - The name of the function-
+ * @param name - The name of the function.
  * @param parameters - The parameters of the function.
  * @returns - The function signature.
  */
 export function decodeFunctionSignature(name: string, parameters: ABIParameter[]) {
   return new FunctionSignatureDecoder(name, parameters).decode();
 }
+
+/**
+ * Decodes a function signature from the name and parameters including parameter names.
+ * @param name - The name of the function.
+ * @param parameters - The parameters of the function.
+ * @returns - The user-friendly function signature.
+ */
+export function decodeFunctionSignatureWithParameterNames(name: string, parameters: ABIParameter[]) {
+  return new FunctionSignatureDecoder(name, parameters, true).decode();
+}