chore: simplify compilation flow to write to file immediately (#5265)

# Description

## Problem\*

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

## Summary\*

This PR pulls across the changes from
AztecProtocol/aztec-packages#6488 to avoid
making changes in aztec-packages unnecessarily and get around the CI
issues over there.

## Additional Context



## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[For Experimental Features]** 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/nargo_cli/src/cli/compile_cmd.rs

@@ -3,15 +3,14 @@ use std::path::Path;
 use std::time::Duration;
 
 use fm::FileManager;
-use nargo::artifacts::program::ProgramArtifact;
 use nargo::ops::{collect_errors, compile_contract, compile_program, report_errors};
 use nargo::package::Package;
 use nargo::workspace::Workspace;
 use nargo::{insert_all_files_for_workspace_into_file_manager, parse_all};
 use nargo_toml::{get_package_manifest, resolve_workspace_from_toml, PackageSelection};
 use noirc_driver::file_manager_with_stdlib;
 use noirc_driver::NOIR_ARTIFACT_VERSION_STRING;
-use noirc_driver::{CompilationResult, CompileOptions, CompiledContract, CompiledProgram};
+use noirc_driver::{CompilationResult, CompileOptions, CompiledContract};
 
 use noirc_frontend::graph::CrateName;
 
@@ -121,72 +120,43 @@ pub(super) fn compile_workspace_full(
     let compiled_workspace =
         compile_workspace(&workspace_file_manager, &parsed_files, workspace, compile_options);
 
-    let (compiled_programs, compiled_contracts) = report_errors(
+    report_errors(
         compiled_workspace,
         &workspace_file_manager,
         compile_options.deny_warnings,
         compile_options.silence_warnings,
     )?;
 
-    let (binary_packages, contract_packages): (Vec<_>, Vec<_>) = workspace
-        .into_iter()
-        .filter(|package| !package.is_library())
-        .cloned()
-        .partition(|package| package.is_binary());
-
-    // Save build artifacts to disk.
-    for (package, program) in binary_packages.into_iter().zip(compiled_programs) {
-        let program = nargo::ops::transform_program(program, compile_options.expression_width);
-        save_program(program.clone(), &package, &workspace.target_directory_path());
-    }
-    let circuit_dir = workspace.target_directory_path();
-    for (package, contract) in contract_packages.into_iter().zip(compiled_contracts) {
-        let contract = nargo::ops::transform_contract(contract, compile_options.expression_width);
-        save_contract(contract, &package, &circuit_dir, compile_options.show_artifact_paths);
-    }
-
     Ok(())
 }
 
-pub(super) fn compile_workspace(
+fn compile_workspace(
     file_manager: &FileManager,
     parsed_files: &ParsedFiles,
     workspace: &Workspace,
     compile_options: &CompileOptions,
-) -> CompilationResult<(Vec<CompiledProgram>, Vec<CompiledContract>)> {
+) -> CompilationResult<()> {
     let (binary_packages, contract_packages): (Vec<_>, Vec<_>) = workspace
         .into_iter()
         .filter(|package| !package.is_library())
         .cloned()
         .partition(|package| package.is_binary());
 
     // Compile all of the packages in parallel.
-    let program_results: Vec<CompilationResult<CompiledProgram>> = binary_packages
-        .par_iter()
-        .map(|package| {
-            let program_artifact_path = workspace.package_build_path(package);
-            let cached_program: Option<CompiledProgram> =
-                read_program_from_file(program_artifact_path)
-                    .ok()
-                    .filter(|p| p.noir_version == NOIR_ARTIFACT_VERSION_STRING)
-                    .map(|p| p.into());
-
-            compile_program(file_manager, parsed_files, package, compile_options, cached_program)
-        })
-        .collect();
-    let contract_results: Vec<CompilationResult<CompiledContract>> = contract_packages
-        .par_iter()
-        .map(|package| compile_contract(file_manager, parsed_files, package, compile_options))
-        .collect();
-
-    // Collate any warnings/errors which were encountered during compilation.
-    let compiled_programs = collect_errors(program_results);
-    let compiled_contracts = collect_errors(contract_results);
+    let program_warnings_or_errors: CompilationResult<()> =
+        compile_programs(file_manager, parsed_files, workspace, &binary_packages, compile_options);
+    let contract_warnings_or_errors: CompilationResult<()> = compiled_contracts(
+        file_manager,
+        parsed_files,
+        &contract_packages,
+        compile_options,
+        &workspace.target_directory_path(),
+    );
 
-    match (compiled_programs, compiled_contracts) {
-        (Ok((programs, program_warnings)), Ok((contracts, contract_warnings))) => {
+    match (program_warnings_or_errors, contract_warnings_or_errors) {
+        (Ok((_, program_warnings)), Ok((_, contract_warnings))) => {
             let warnings = [program_warnings, contract_warnings].concat();
-            Ok(((programs, contracts), warnings))
+            Ok(((), warnings))
         }
         (Err(program_errors), Err(contract_errors)) => {
             Err([program_errors, contract_errors].concat())
@@ -195,22 +165,79 @@ pub(super) fn compile_workspace(
     }
 }
 
-pub(super) fn save_program(program: CompiledProgram, package: &Package, circuit_dir: &Path) {
-    let program_artifact = ProgramArtifact::from(program.clone());
-    save_program_to_file(&program_artifact, &package.name, circuit_dir);
+fn compile_programs(
+    file_manager: &FileManager,
+    parsed_files: &ParsedFiles,
+    workspace: &Workspace,
+    binary_packages: &[Package],
+    compile_options: &CompileOptions,
+) -> CompilationResult<()> {
+    let load_cached_program = |package| {
+        let program_artifact_path = workspace.package_build_path(package);
+        read_program_from_file(program_artifact_path)
+            .ok()
+            .filter(|p| p.noir_version == NOIR_ARTIFACT_VERSION_STRING)
+            .map(|p| p.into())
+    };
+
+    let program_results: Vec<CompilationResult<()>> = binary_packages
+        .par_iter()
+        .map(|package| {
+            let (program, warnings) = compile_program(
+                file_manager,
+                parsed_files,
+                package,
+                compile_options,
+                load_cached_program(package),
+            )?;
+            let program = nargo::ops::transform_program(program, compile_options.expression_width);
+            save_program_to_file(
+                &program.clone().into(),
+                &package.name,
+                workspace.target_directory_path(),
+            );
+            Ok(((), warnings))
+        })
+        .collect();
+
+    // Collate any warnings/errors which were encountered during compilation.
+    collect_errors(program_results).map(|(_, warnings)| ((), warnings))
+}
+
+fn compiled_contracts(
+    file_manager: &FileManager,
+    parsed_files: &ParsedFiles,
+    contract_packages: &[Package],
+    compile_options: &CompileOptions,
+    target_dir: &Path,
+) -> CompilationResult<()> {
+    let contract_results: Vec<CompilationResult<()>> = contract_packages
+        .par_iter()
+        .map(|package| {
+            let (contract, warnings) =
+                compile_contract(file_manager, parsed_files, package, compile_options)?;
+            let contract =
+                nargo::ops::transform_contract(contract, compile_options.expression_width);
+            save_contract(contract, package, target_dir, compile_options.show_artifact_paths);
+            Ok(((), warnings))
+        })
+        .collect();
+
+    // Collate any warnings/errors which were encountered during compilation.
+    collect_errors(contract_results).map(|(_, warnings)| ((), warnings))
 }
 
 fn save_contract(
     contract: CompiledContract,
     package: &Package,
-    circuit_dir: &Path,
+    target_dir: &Path,
     show_artifact_paths: bool,
 ) {
     let contract_name = contract.name.clone();
     let artifact_path = save_contract_to_file(
         &contract.into(),
         &format!("{}-{}", package.name, contract_name),
-        circuit_dir,
+        target_dir,
     );
     if show_artifact_paths {
         println!("Saved contract artifact to: {}", artifact_path.display());