feat(nargo): Support custom entry points specified in TOML (#2158)

crates/nargo_cli/src/errors.rs

@@ -123,8 +123,13 @@ pub(crate) enum ManifestError {
     #[error("Unxpected workspace definition found in {0}")]
     UnexpectedWorkspace(PathBuf),
 
-    #[error("Cannot find file {0} which is required due to specifying the `{1}` package type")]
-    MissingEntryFile(PathBuf, PackageType),
+    #[error("Cannot find file {entry} which was specified as the `entry` field in {toml}")]
+    MissingEntryFile { toml: PathBuf, entry: PathBuf },
+
+    #[error(
+        r#"Cannot find file {entry} which is defaulted due to specifying `type = "{package_type}"` in {toml}"#
+    )]
+    MissingDefaultEntryFile { toml: PathBuf, entry: PathBuf, package_type: PackageType },
 
     /// Invalid character `-` in package name
     #[error("invalid character `-` in package name")]

crates/nargo_cli/src/manifest.rs

@@ -48,22 +48,44 @@ impl PackageConfig {
             None => return Err(ManifestError::MissingPackageType(root_dir.join("Nargo.toml"))),
         };
 
-        let entry_path = match package_type {
-            PackageType::Library => root_dir.join("src").join("lib").with_extension(FILE_EXTENSION),
-            PackageType::Binary => root_dir.join("src").join("main").with_extension(FILE_EXTENSION),
+        let entry_path = if let Some(entry_path) = &self.package.entry {
+            let custom_entry_path = root_dir.join(entry_path);
+            if custom_entry_path.exists() {
+                custom_entry_path
+            } else {
+                return Err(ManifestError::MissingEntryFile {
+                    toml: root_dir.join("Nargo.toml"),
+                    entry: custom_entry_path,
+                });
+            }
+        } else {
+            let default_entry_path = match package_type {
+                PackageType::Library => {
+                    root_dir.join("src").join("lib").with_extension(FILE_EXTENSION)
+                }
+                PackageType::Binary => {
+                    root_dir.join("src").join("main").with_extension(FILE_EXTENSION)
+                }
+            };
+
+            if default_entry_path.exists() {
+                default_entry_path
+            } else {
+                return Err(ManifestError::MissingDefaultEntryFile {
+                    toml: root_dir.join("Nargo.toml"),
+                    entry: default_entry_path,
+                    package_type,
+                });
+            }
         };
 
-        if entry_path.exists() {
-            Ok(Package {
-                root_dir: root_dir.to_path_buf(),
-                entry_path,
-                package_type,
-                name,
-                dependencies,
-            })
-        } else {
-            Err(ManifestError::MissingEntryFile(entry_path, package_type))
-        }
+        Ok(Package {
+            root_dir: root_dir.to_path_buf(),
+            entry_path,
+            package_type,
+            name,
+            dependencies,
+        })
     }
 }
 
@@ -120,6 +142,7 @@ struct PackageMetadata {
     name: Option<String>,
     #[serde(alias = "type")]
     package_type: Option<String>,
+    entry: Option<PathBuf>,
     description: Option<String>,
     authors: Option<Vec<String>>,
     // If not compiler version is supplied, the latest is used

crates/nargo_cli/tests/test_data/config.toml

@@ -2,4 +2,4 @@ exclude = []
 
 
 # List of tests (as their directory name) expecting to fail: if the test pass, we report an error.
-fail = ["brillig_assert_fail", "dep_impl_primitive", "depend_on_bin", "workspace_fail", "workspace_missing_toml"]
+fail = ["brillig_assert_fail", "custom_entry_not_found", "dep_impl_primitive", "depend_on_bin", "workspace_fail", "workspace_missing_toml"]

crates/nargo_cli/tests/test_data/custom_entry/Nargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "custom_entry"
+type = "bin"
+entry = "src/foobarbaz.nr"
+authors = [""]
+compiler_version = "0.1"
+
+[dependencies]

crates/nargo_cli/tests/test_data/custom_entry/Prover.toml

@@ -0,0 +1 @@
+x = "1"

crates/nargo_cli/tests/test_data/custom_entry/src/foobarbaz.nr

@@ -0,0 +1,3 @@
+fn main(x: Field) {
+    assert(x == 1);
+}

crates/nargo_cli/tests/test_data/custom_entry/target/custom_entry.json

@@ -0,0 +1 @@
+{"backend":"acvm-backend-barretenberg","abi":{"parameters":[{"name":"x","type":{"kind":"field"},"visibility":"private"}],"param_witnesses":{"x":[1]},"return_type":null,"return_witnesses":[]},"bytecode":"H4sIAAAAAAAA/82SMQ7DIAxFTSAdexYbQzBbr1JUcv8jtAODRbPVSP2LEUjP/v7sALDDt7ZRH6PibyKnWIxHSr3ETkxPjLVJxpTbISSUJb+iMHdJUmqrBSsl7nTmyueAbYYs/2G4C//O2P9mx0I9r1fnMGWn328LPMHUZ97j/eLOtPmKkPwCbgC7D7vKd7DPCBXyr3fqphm13hKQ6RMhBQAA","proving_key":null,"verification_key":null}

crates/nargo_cli/tests/test_data/custom_entry_not_found/Nargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "custom_entry"
+type = "bin"
+# Testing that this file is missing and doesn't fallback to default `main.nr` file
+entry = "src/foobarbaz.nr"
+authors = [""]
+compiler_version = "0.1"
+
+[dependencies]

crates/nargo_cli/tests/test_data/custom_entry_not_found/Prover.toml

@@ -0,0 +1 @@
+x = "1"

crates/nargo_cli/tests/test_data/custom_entry_not_found/src/main.nr

@@ -0,0 +1,3 @@
+fn main(x: Field) {
+    assert(x == 1);
+}