refactor(forge build): update cache_local_signatures to accept an optional cache_dir

No more need to unwrap the option value returned  foundry's `config` crate

Author: mablr

crates/cli/src/utils/cmd.rs

@@ -440,7 +440,14 @@ pub async fn print_traces(
 
 /// Traverse the artifacts in the project to generate local signatures and merge them into the cache
 /// file.
-pub fn cache_local_signatures(output: &ProjectCompileOutput, cache_dir: &Path) -> Result<()> {
+pub fn cache_local_signatures(
+    output: &ProjectCompileOutput,
+    cache_dir: Option<PathBuf>,
+) -> Result<()> {
+    let Some(cache_dir) = cache_dir else {
+        eyre::bail!("Failed to get `cache_dir` to generate local signatures.");
+    };
+
     let path = cache_dir.join("signatures");
     let mut signatures = SignaturesCache::load(&path);
     for (_, artifact) in output.artifacts() {

crates/forge/src/cmd/build.rs

@@ -104,7 +104,7 @@ impl BuildArgs {
         let output = compiler.compile(&project)?;
 
         // Cache project selectors.
-        cache_local_signatures(&output, &Config::foundry_cache_dir().unwrap())?;
+        cache_local_signatures(&output, Config::foundry_cache_dir())?;
 
         if format_json && !self.names && !self.sizes {
             sh_println!("{}", serde_json::to_string_pretty(&output.output())?)?;

crates/forge/src/cmd/selectors.rs

@@ -95,7 +95,7 @@ impl SelectorsSubcommands {
                 // compile the project to get the artifacts/abis
                 let project = build_args.project()?;
                 let outcome = ProjectCompiler::new().quiet(true).compile(&project)?;
-                cache_local_signatures(&outcome, &Config::foundry_cache_dir().unwrap())?
+                cache_local_signatures(&outcome, Config::foundry_cache_dir())?;
             }
             Self::Upload { contract, all, project_paths } => {
                 let build_args = BuildOpts {