feat: allow passing custom foreign call handlers when creating proofs…

… in NoirJS (#3764)

… 

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

This PR modifies the default foreign call handler for JS to ignore
`print` foreign calls so that they don't halt execution. If users want
to get these values out and display them then they should provide a
custom handler for the time being.

The other change made is allowing passing this custom handler when
generating a proof.

## Additional Context


## Documentation\*

Check one:
- [ ] No documentation needed.
- [x] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

tooling/noir_js/src/program.ts

@@ -67,12 +67,12 @@ export class Noir {
    *
    * @example
    * ```typescript
-   * async generateFinalproof(input)
+   * async generateFinalProof(input)
    * ```
    *
    */
-  async generateFinalProof(inputs: InputMap): Promise<ProofData> {
-    const { witness } = await this.execute(inputs);
+  async generateFinalProof(inputs: InputMap, foreignCallHandler?: ForeignCallHandler): Promise<ProofData> {
+    const { witness } = await this.execute(inputs, foreignCallHandler);
     return this.getBackend().generateFinalProof(witness);
   }
 

tooling/noir_js/src/witness_generation.ts

@@ -3,7 +3,14 @@ import { base64Decode } from './base64_decode.js';
 import { executeCircuit, WitnessMap, ForeignCallHandler, ForeignCallInput } from '@noir-lang/acvm_js';
 import { CompiledCircuit } from '@noir-lang/types';
 
-const defaultForeignCallHandler: ForeignCallHandler = (name: string, args: ForeignCallInput[]) => {
+const defaultForeignCallHandler: ForeignCallHandler = async (name: string, args: ForeignCallInput[]) => {
+  if (name == 'print') {
+    // By default we do not print anything for `print` foreign calls due to a need for formatting,
+    // however we provide an empty response in order to not halt execution.
+    //
+    // If a user needs to print values then they should provide a custom foreign call handler.
+    return [];
+  }
   throw Error(`Unexpected oracle during execution: ${name}(${args.join(', ')})`);
 };
 

tooling/noir_js/test/noir_compiled_examples/assert_lt/src/main.nr

@@ -1,4 +1,9 @@
+use dep::std;
+
 fn main(x: u64, y: pub u64) -> pub u64 {
+    // We include a println statement to show that noirJS will ignore this and continue execution
+    std::println("foo");
+
     assert(x < y);
     x + y
 }

tooling/noir_js/test/noir_compiled_examples/assert_lt/target/assert_lt.json

@@ -1 +1 @@
-{"noir_version":"0.19.4+55670ff82c270534a4bdb999ab0de5cea7017093","hash":4729344722355302200,"backend":"acvm-backend-barretenberg","abi":{"parameters":[{"name":"x","type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"private"},{"name":"y","type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"public"}],"param_witnesses":{"x":[{"start":1,"end":2}],"y":[{"start":2,"end":3}]},"return_type":{"abi_type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"public"},"return_witnesses":[5]},"bytecode":"H4sIAAAAAAAA/81V4WrDIBDWmGxsP/YE+5FH8KI2+q/0TRJi2GAjY8j6+itM4eraQOsVeiCnF/1y9513PjLGntmf8MOoot6idRXXIs5zSbZt1LJMgCMsJTda+77zoGCQnRutkdqMGwsWjDVTZ5XyVtveja6XDrTyMBun5ghWXe8X5IYToZNhY15F1PVhNFlukn2H9nOkOcrJDp05tYefwXlCtnT+BX0vDf4fGfjnVJgiEpnjll4oQeejTEmtEWYSQczHrYqqFOuBkM81/i70U2Z+giCMuSbMawF/qw3unutmLc+yTI7qRJYJUNZJw+j7TsI894CkecOOm396IF6jHkLwn1+hDUs7TFO7fw9v7fLjv+ePZf8LJenp6WEIAAA="}
+{"noir_version":"0.20.0+010fdb69616f47fc0a9f252a65a903316d3cbe80","hash":17538653710107541030,"backend":"acvm-backend-barretenberg","abi":{"parameters":[{"name":"x","type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"private"},{"name":"y","type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"public"}],"param_witnesses":{"x":[{"start":1,"end":2}],"y":[{"start":2,"end":3}]},"return_type":{"abi_type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"public"},"return_witnesses":[5]},"bytecode":"H4sIAAAAAAAA/9Wa627aMBiGHcKhBBLOR+0Hl+Ak5PQP9U6gBK3SNqoqWm9kFzzMYu2DujhbPjvFEkrsJu/7vJ+TFDAtQkiH/GnG6VXLtxvQr+V9Mx/jx5pE3Db5lpZqYahI96Ba91e+bee1g60J6objS90mehbqN8nfuUbSpLAeNVAjXg++bZxeD/m+k9esjlyz6+t3A/p1MFfYvkyzharpPrXzmsFmXPU3YL8F8jUV5HvA1aRMs42qGe2YhgVqwuvH2Tvg721QLwu5Xgbw5Lq8bynz9Tye8Vb+joCjozF/R5lveJ7/riR/V8DR1Zi/q8w3TJiGLclvCzhsjfltZb5hyjQcSX5HwOFozO8o8w3XTKMnyd8TcPQ05od8RVmtilnxff0t0+hL8vcFHH2N+SFfUVarYlZ838hnGgNJ/oGAY6Ax/0CZb3R+rgwl+YcCjqHG/ENlvtH5fdVIkn8k4BhpzA/5irJ274jVrpgV3zeMmMZYkn8s4BhrzA/5irJaFbPi+3pPTGMiyT8RcEw05od8RVmtilnxfcPzXE0l+acCjqnG/FNlvmHANGaS/DMBx0xjfshXlNW+I9bRHbEOKmbF9w1jpjGX5J8LOOYa80O+oqzWHbH2KmbF9/XPnwUXkvwLAcdCY/6FMt9ozzSWkvxLAcdSY/4l8MVet3gAmV9en39kHKAOYPg+X2xlzQRjXOALOIeDtsj7hR60qpnk/eolAWNYPgbQ8k/fTK7TyEtd391SL9nFAV0HuzB2YzeIg70X+34ar+Mo2SURTdy1n7qHIPEPuVjt/7nc6wFBdDRtWFe46tgAE18D44/geLgCb4A5eQTniI4xPtBpgzF+vkMUXljQHEvTJJc/T+C6ZS8oE4+R8kmtk8vlWELwfxKg6qYqq9VErOet+v0jJ73idE3EzHXEeS1Rv5sPuM9839yaZ1quXdwntFxzMe+TBsF/7nDNj/6B8P0GuXz4848R/B3INsvS7y/ZKjuutvv96u05+7o6/kxfD9+Ob78Bhjydn08mAAA="}