chore!: Remove backend field from artifacts (#3819)

# Description

In `kw/remove-partial-backend-code` we removed the opcodes supported
feature, which means that artifacts are no longer compiled based on a
backends feature set.


Closes #1388 

## Problem\*

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

## Summary\*



## Additional Context



## Documentation\*

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

# PR Checklist\*

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

---------

Co-authored-by: Tom French <15848336+TomAFrench@users.noreply.github.com>

compiler/wasm/src/compile.rs

@@ -20,8 +20,6 @@ use wasm_bindgen::prelude::*;
 
 use crate::errors::{CompileError, JsCompileError};
 
-const BACKEND_IDENTIFIER: &str = "acvm-backend-barretenberg";
-
 #[wasm_bindgen(typescript_custom_section)]
 const DEPENDENCY_GRAPH: &'static str = r#"
 export type DependencyGraph = {
@@ -32,14 +30,12 @@ export type DependencyGraph = {
 export type CompiledContract = {
     noir_version: string;
     name: string;
-    backend: string;
     functions: Array<any>;
     events: Array<any>;
 };
 
 export type CompiledProgram = {
     noir_version: string;
-    backend: string;
     abi: any;
     bytecode: string;
 }
@@ -285,7 +281,6 @@ pub(crate) fn preprocess_program(program: CompiledProgram) -> CompileResult {
 
     let preprocessed_program = PreprocessedProgram {
         hash: program.hash,
-        backend: String::from(BACKEND_IDENTIFIER),
         abi: program.abi,
         noir_version: NOIR_ARTIFACT_VERSION_STRING.to_string(),
         bytecode: program.circuit,
@@ -316,7 +311,6 @@ pub(crate) fn preprocess_contract(contract: CompiledContract) -> CompileResult {
     let preprocessed_contract = PreprocessedContract {
         noir_version: String::from(NOIR_ARTIFACT_VERSION_STRING),
         name: contract.name,
-        backend: String::from(BACKEND_IDENTIFIER),
         functions: preprocessed_functions,
         events: contract.events,
     };

compiler/wasm/test/browser/index.test.ts

@@ -42,7 +42,6 @@ describe('noir wasm', () => {
       expect(wasmCircuit.program.noir_version).to.eq(cliCircuit.noir_version);
       expect(wasmCircuit.program.bytecode).to.eq(cliCircuit.bytecode);
       expect(wasmCircuit.program.abi).to.deep.eq(cliCircuit.abi);
-      expect(wasmCircuit.program.backend).to.eq(cliCircuit.backend);
     }).timeout(20e3); // 20 seconds
   });
 
@@ -81,7 +80,6 @@ describe('noir wasm', () => {
       expect(wasmCircuit.program.noir_version).to.eq(cliCircuit.noir_version);
       expect(wasmCircuit.program.bytecode).to.eq(cliCircuit.bytecode);
       expect(wasmCircuit.program.abi).to.deep.eq(cliCircuit.abi);
-      expect(wasmCircuit.program.backend).to.eq(cliCircuit.backend);
     }).timeout(20e3); // 20 seconds
   });
 });

compiler/wasm/test/node/index.test.ts

@@ -36,7 +36,6 @@ describe('noir wasm compilation', () => {
       expect(wasmCircuit.program.noir_version).to.eq(cliCircuit.noir_version);
       expect(wasmCircuit.program.bytecode).to.eq(cliCircuit.bytecode);
       expect(wasmCircuit.program.abi).to.deep.eq(cliCircuit.abi);
-      expect(wasmCircuit.program.backend).to.eq(cliCircuit.backend);
     }).timeout(10e3);
   });
 
@@ -71,7 +70,6 @@ describe('noir wasm compilation', () => {
       expect(wasmCircuit.program.noir_version).to.eq(cliCircuit.noir_version);
       expect(wasmCircuit.program.bytecode).to.eq(cliCircuit.bytecode);
       expect(wasmCircuit.program.abi).to.deep.eq(cliCircuit.abi);
-      expect(wasmCircuit.program.backend).to.eq(cliCircuit.backend);
     }).timeout(10e3);
   });
 
@@ -121,7 +119,6 @@ describe('noir wasm compilation', () => {
       expect(wasmCircuit.program.noir_version).to.eq(cliCircuit.noir_version);
       expect(wasmCircuit.program.bytecode).to.eq(cliCircuit.bytecode);
       expect(wasmCircuit.program.abi).to.deep.eq(cliCircuit.abi);
-      expect(wasmCircuit.program.backend).to.eq(cliCircuit.backend);
     }).timeout(10e3);
 
     it('matching nargos compilation - context-implementation-compile-api', async () => {
@@ -147,7 +144,6 @@ describe('noir wasm compilation', () => {
       expect(wasmCircuit.program.noir_version).to.eq(cliCircuit.noir_version);
       expect(wasmCircuit.program.bytecode).to.eq(cliCircuit.bytecode);
       expect(wasmCircuit.program.abi).to.deep.eq(cliCircuit.abi);
-      expect(wasmCircuit.program.backend).to.eq(cliCircuit.backend);
     }).timeout(10e3);
   });
 });

tooling/backend_interface/src/lib.rs

@@ -8,7 +8,7 @@ mod download;
 mod proof_system;
 mod smart_contract;
 
-use bb_abstraction_leaks::ACVM_BACKEND_BARRETENBERG;
+pub use bb_abstraction_leaks::ACVM_BACKEND_BARRETENBERG;
 use bb_abstraction_leaks::BB_VERSION;
 use cli::VersionCommand;
 pub use download::download_backend;

tooling/nargo/src/artifacts/contract.rs

@@ -14,8 +14,6 @@ pub struct PreprocessedContract {
     pub noir_version: String,
     /// The name of the contract.
     pub name: String,
-    /// The identifier of the proving backend which this contract has been compiled for.
-    pub backend: String,
     /// Each of the contract's functions are compiled into a separate program stored in this `Vec`.
     pub functions: Vec<PreprocessedContractFunction>,
     /// All the events defined inside the contract scope.

tooling/nargo/src/artifacts/program.rs

@@ -17,7 +17,6 @@ pub struct PreprocessedProgram {
     /// Used to short-circuit compilation in the case of the source code not changing since the last compilation.
     pub hash: u64,
 
-    pub backend: String,
     pub abi: Abi,
 
     #[serde(

tooling/nargo_cli/src/backends.rs

@@ -7,7 +7,7 @@ fn active_backend_file_path() -> PathBuf {
     backends_directory().join(".selected_backend")
 }
 
-pub(crate) const ACVM_BACKEND_BARRETENBERG: &str = "acvm-backend-barretenberg";
+pub(crate) use backend_interface::ACVM_BACKEND_BARRETENBERG;
 
 pub(crate) fn clear_active_backend() {
     let active_backend_file = active_backend_file_path();

tooling/nargo_cli/src/cli/compile_cmd.rs

@@ -29,9 +29,6 @@ use super::fs::program::{
 use super::NargoConfig;
 use rayon::prelude::*;
 
-// TODO(#1388): pull this from backend.
-const BACKEND_IDENTIFIER: &str = "acvm-backend-barretenberg";
-
 /// Compile the program and its secret execution trace into ACIR format
 #[derive(Debug, Clone, Args)]
 pub(crate) struct CompileCommand {
@@ -233,7 +230,6 @@ fn save_program(
 ) {
     let preprocessed_program = PreprocessedProgram {
         hash: program.hash,
-        backend: String::from(BACKEND_IDENTIFIER),
         abi: program.abi,
         noir_version: program.noir_version,
         bytecode: program.circuit,
@@ -275,7 +271,6 @@ fn save_contract(contract: CompiledContract, package: &Package, circuit_dir: &Pa
     let preprocessed_contract = PreprocessedContract {
         noir_version: contract.noir_version,
         name: contract.name,
-        backend: String::from(BACKEND_IDENTIFIER),
         functions: preprocessed_functions,
         events: contract.events,
     };

tooling/nargo_cli/src/cli/init_cmd.rs

@@ -1,4 +1,3 @@
-use crate::backends::Backend;
 use crate::errors::CliError;
 
 use super::fs::{create_named_dir, write_to_file};
@@ -34,12 +33,7 @@ const BIN_EXAMPLE: &str = include_str!("./noir_template_files/binary.nr");
 const CONTRACT_EXAMPLE: &str = include_str!("./noir_template_files/contract.nr");
 const LIB_EXAMPLE: &str = include_str!("./noir_template_files/library.nr");
 
-pub(crate) fn run(
-    // Backend is currently unused, but we might want to use it to inform the "new" template in the future
-    _backend: &Backend,
-    args: InitCommand,
-    config: NargoConfig,
-) -> Result<(), CliError> {
+pub(crate) fn run(args: InitCommand, config: NargoConfig) -> Result<(), CliError> {
     let package_name = match args.name {
         Some(name) => name,
         None => {

tooling/nargo_cli/src/cli/mod.rs

@@ -100,7 +100,7 @@ pub(crate) fn start_cli() -> eyre::Result<()> {
 
     match command {
         NargoCommand::New(args) => new_cmd::run(&backend, args, config),
-        NargoCommand::Init(args) => init_cmd::run(&backend, args, config),
+        NargoCommand::Init(args) => init_cmd::run(args, config),
         NargoCommand::Check(args) => check_cmd::run(&backend, args, config),
         NargoCommand::Compile(args) => compile_cmd::run(&backend, args, config),
         NargoCommand::Debug(args) => debug_cmd::run(&backend, args, config),

tooling/nargo_toml/src/lib.rs

@@ -270,7 +270,6 @@ struct PackageMetadata {
     // We also state that ACIR and the compiler will upgrade in lockstep.
     // so you will not need to supply an ACIR and compiler version
     compiler_version: Option<String>,
-    backend: Option<String>,
     license: Option<String>,
 }