feat: don't request Solc JSON AST unless absolutely necessary

crates/cli/src/opts/build/mod.rs

@@ -15,6 +15,10 @@ pub use self::paths::ProjectPathsArgs;
 #[derive(Clone, Debug, Default, Serialize, Parser)]
 #[clap(next_help_heading = "Compiler options")]
 pub struct CompilerArgs {
+    /// Includes the AST as JSON in the compiler output.
+    #[clap(long, help_heading = "Compiler options")]
+    pub ast: bool,
+
     /// The target EVM version.
     #[clap(long, value_name = "VERSION")]
     #[serde(skip_serializing_if = "Option::is_none")]

crates/config/README.md

@@ -138,6 +138,7 @@ extra_output_files = []
 names = false
 sizes = false
 via_ir = false
+ast = false
 # caches storage retrieved locally for certain chains and endpoints
 # can also be restricted to `chains = ["optimism", "mainnet"]`
 # by default all endpoints will be cached, alternative options are "remote" for only caching non localhost endpoints and "<regex>"

crates/config/src/lib.rs

@@ -318,6 +318,8 @@ pub struct Config {
     /// If set to true, changes compilation pipeline to go through the Yul intermediate
     /// representation.
     pub via_ir: bool,
+    /// Whether to include the AST as JSON in the compiler output.
+    pub ast: bool,
     /// RPC storage caching settings determines what chains and endpoints to cache
     pub rpc_storage_caching: StorageCachingConfig,
     /// Disables storage caching entirely. This overrides any settings made in
@@ -1064,7 +1066,7 @@ impl Config {
             }
         }
 
-        Ok(Settings {
+        let mut settings = Settings {
             libraries: self.libraries_with_remappings()?,
             optimizer: self.optimizer(),
             evm_version: Some(self.evm_version),
@@ -1087,7 +1089,13 @@ impl Config {
             // Set with `with_extra_output` below.
             output_selection: Default::default(),
         }
-        .with_extra_output(self.configured_artifacts_handler().output_selection()))
+        .with_extra_output(self.configured_artifacts_handler().output_selection());
+
+        if self.ast {
+            settings = settings.with_ast();
+        }
+
+        Ok(settings)
     }
 
     /// Returns the default figment
@@ -1877,6 +1885,7 @@ impl Default for Config {
             ignored_file_paths: vec![],
             deny_warnings: false,
             via_ir: false,
+            ast: false,
             rpc_storage_caching: Default::default(),
             rpc_endpoints: Default::default(),
             etherscan: Default::default(),

crates/forge/bin/cmd/coverage.rs

@@ -88,6 +88,9 @@ impl CoverageArgs {
         // Set fuzz seed so coverage reports are deterministic
         config.fuzz.seed = Some(U256::from_be_bytes(STATIC_FUZZ_SEED));
 
+        // Coverage analysis requires the Solc AST output.
+        config.ast = true;
+
         let (project, output) = self.build(&config)?;
         p_println!(!self.opts.silent => "Analysing contracts...");
         let report = self.prepare(&config, output.clone())?;
@@ -99,50 +102,42 @@ impl CoverageArgs {
     /// Builds the project.
     fn build(&self, config: &Config) -> Result<(Project, ProjectCompileOutput)> {
         // Set up the project
-        let project = {
-            let mut project = config.ephemeral_no_artifacts_project()?;
-
-            if self.ir_minimum {
-                // TODO: How to detect solc version if the user does not specify a solc version in
-                // config  case1: specify local installed solc ?
-                //  case2: multiple solc versions used and  auto_detect_solc == true
-                if let Some(SolcReq::Version(version)) = &config.solc {
-                    if *version < Version::new(0, 8, 13) {
-                        return Err(eyre::eyre!(
+        let mut project = config.ephemeral_no_artifacts_project()?;
+        if self.ir_minimum {
+            // TODO: How to detect solc version if the user does not specify a solc version in
+            // config  case1: specify local installed solc ?
+            //  case2: multiple solc versions used and  auto_detect_solc == true
+            if let Some(SolcReq::Version(version)) = &config.solc {
+                if *version < Version::new(0, 8, 13) {
+                    return Err(eyre::eyre!(
                             "viaIR with minimum optimization is only available in Solidity 0.8.13 and above."
                         ));
-                    }
                 }
-
-                // print warning message
-                p_println!(!self.opts.silent => "{}",
-                Paint::yellow(
-                concat!(
-                "Warning! \"--ir-minimum\" flag enables viaIR with minimum optimization, which can result in inaccurate source mappings.\n",
-                "Only use this flag as a workaround if you are experiencing \"stack too deep\" errors.\n",
-                "Note that \"viaIR\" is only available in Solidity 0.8.13 and above.\n",
-                "See more:\n",
-                "https://github.com/foundry-rs/foundry/issues/3357\n"
-                )));
-
-                // Enable viaIR with minimum optimization
-                // https://github.com/ethereum/solidity/issues/12533#issuecomment-1013073350
-                // And also in new releases of solidity:
-                // https://github.com/ethereum/solidity/issues/13972#issuecomment-1628632202
-                project.solc_config.settings =
-                    project.solc_config.settings.with_via_ir_minimum_optimization()
-            } else {
-                project.solc_config.settings.optimizer.disable();
-                project.solc_config.settings.optimizer.runs = None;
-                project.solc_config.settings.optimizer.details = None;
-                project.solc_config.settings.via_ir = None;
             }
 
-            // Coverage analysis requires the Solc AST output.
-            project.solc_config.settings = project.solc_config.settings.with_ast();
-
-            project
-        };
+            // print warning message
+            p_println!(!self.opts.silent => "{}",
+            Paint::yellow(
+            concat!(
+            "Warning! \"--ir-minimum\" flag enables viaIR with minimum optimization, which can result in inaccurate source mappings.\n",
+            "Only use this flag as a workaround if you are experiencing \"stack too deep\" errors.\n",
+            "Note that \"viaIR\" is only available in Solidity 0.8.13 and above.\n",
+            "See more:\n",
+            "https://github.com/foundry-rs/foundry/issues/3357\n"
+            )));
+
+            // Enable viaIR with minimum optimization
+            // https://github.com/ethereum/solidity/issues/12533#issuecomment-1013073350
+            // And also in new releases of solidity:
+            // https://github.com/ethereum/solidity/issues/13972#issuecomment-1628632202
+            project.solc_config.settings =
+                project.solc_config.settings.with_via_ir_minimum_optimization()
+        } else {
+            project.solc_config.settings.optimizer.disable();
+            project.solc_config.settings.optimizer.runs = None;
+            project.solc_config.settings.optimizer.details = None;
+            project.solc_config.settings.via_ir = None;
+        }
 
         let output = ProjectCompiler::default()
             .compile(&project)?

crates/forge/bin/cmd/flatten.rs

@@ -36,11 +36,10 @@ impl FlattenArgs {
 
         // flatten is a subset of `BuildArgs` so we can reuse that to get the config
         let build_args = CoreBuildArgs { project_paths, ..Default::default() };
-        let config = build_args.try_load_config_emit_warnings()?;
-        let mut project = config.ephemeral_no_artifacts_project()?;
-
+        let mut config = build_args.try_load_config_emit_warnings()?;
         // `Flattener` uses the typed AST for better flattening results.
-        project.solc_config.settings = project.solc_config.settings.with_ast();
+        config.ast = true;
+        let project = config.ephemeral_no_artifacts_project()?;
 
         let target_path = dunce::canonicalize(target_path)?;
         let compiler_output = ProjectCompiler::new().files([target_path.clone()]).compile(&project);

crates/forge/tests/cli/config.rs

@@ -98,6 +98,7 @@ forgetest!(can_extract_config_values, |prj, cmd| {
         ignored_file_paths: vec![],
         deny_warnings: false,
         via_ir: true,
+        ast: false,
         rpc_storage_caching: StorageCachingConfig {
             chains: CachedChains::None,
             endpoints: CachedEndpoints::Remote,