refactor: determine_ethers_crates

ethers-core/src/macros/ethers_crate.rs

@@ -1,87 +1,83 @@
+//! N.B.:
+//! - crate names must not be [global paths](https://doc.rust-lang.org/reference/paths.html#path-qualifiers)
+//!   since we must be able to override them internally, like in Multicall.
+//!
+//! - [`ETHERS_CRATE_NAMES`] cannot hold [`syn::Path`] because it is not [`Sync`], so the names must
+//!   be parsed at every call.
+
 use cargo_metadata::MetadataCommand;
 use once_cell::sync::Lazy;
+use std::path::PathBuf;
 
-use syn::Path;
-
-/// See `determine_ethers_crates`
+/// Crate names to use in Path resolution.
 ///
-/// This ensures that the `MetadataCommand` is only run once
-static ETHERS_CRATES: Lazy<(&'static str, &'static str, &'static str)> =
-    Lazy::new(determine_ethers_crates);
+/// `(core, contract, providers)`
+type CrateNames = (&'static str, &'static str, &'static str);
 
-/// Convenience function to turn the `ethers_core` name in `ETHERS_CRATE` into a `Path`
-pub fn ethers_core_crate() -> Path {
-    syn::parse_str(ETHERS_CRATES.0).expect("valid path; qed")
-}
-/// Convenience function to turn the `ethers_contract` name in `ETHERS_CRATE` into an `Path`
-pub fn ethers_contract_crate() -> Path {
-    syn::parse_str(ETHERS_CRATES.1).expect("valid path; qed")
-}
-pub fn ethers_providers_crate() -> Path {
-    syn::parse_str(ETHERS_CRATES.2).expect("valid path; qed")
+const DEFAULT_CRATE_NAMES: CrateNames = ("ethers::core", "ethers::contract", "ethers::providers");
+const SUB_CRATE_NAMES: CrateNames = ("ethers_core", "ethers_contract", "ethers_providers");
+
+/// See [`determine_ethers_crates`].
+///
+/// This ensures that the `MetadataCommand` is ran only once.
+static ETHERS_CRATE_NAMES: Lazy<CrateNames> = Lazy::new(determine_ethers_crates);
+
+/// Returns the `core` crate's [`Path`][syn::Path].
+pub fn ethers_core_crate() -> syn::Path {
+    syn::parse_str(ETHERS_CRATE_NAMES.0).unwrap()
 }
 
-/// The crates name to use when deriving macros: (`core`, `contract`)
+/// Returns the `contract` crate's [`Path`][syn::Path].
+pub fn ethers_contract_crate() -> syn::Path {
+    syn::parse_str(ETHERS_CRATE_NAMES.1).unwrap()
+}
+
+/// Returns the `providers` crate's [`Path`][syn::Path].
+pub fn ethers_providers_crate() -> syn::Path {
+    syn::parse_str(ETHERS_CRATE_NAMES.2).unwrap()
+}
+
+/// Determines which crate paths to use by looking at the [metadata][cargo_metadata] of the project.
 ///
-/// We try to determine which crate ident to use based on the dependencies of
-/// the project in which the macro is used. This is useful because the macros,
-/// like `EthEvent` are provided by the `ethers-contract` crate which depends on
-/// `ethers_core`. Most commonly `ethers` will be used as dependency which
-/// reexports all the different crates, essentially `ethers::core` is
-/// `ethers_core` So depending on the dependency used `ethers` ors `ethers_core
-/// | ethers_contract`, we need to use the fitting crate ident when expand the
-/// macros This will attempt to parse the current `Cargo.toml` and check the
-/// ethers related dependencies.
+/// Returns `ethers_*` if *all* necessary dependencies are present, otherwise `ethers::*`.
+fn determine_ethers_crates() -> CrateNames {
+    // always defined in Cargo projects
+    let manifest_dir: PathBuf =
+        std::env::var_os("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR is not defined").into();
+
+    let lock_file = manifest_dir.join("Cargo.lock");
+    let lock_file_existed = lock_file.exists();
+
+    let names = crate_names_from_metadata(manifest_dir).unwrap_or(DEFAULT_CRATE_NAMES);
+
+    // remove the lock file created from running the command
+    if !lock_file_existed && lock_file.exists() {
+        let _ = std::fs::remove_file(lock_file);
+    }
+
+    names
+}
+
+/// Runs [`cargo metadata`][MetadataCommand] from `manifest_dir` and determines the crate names to
+/// use.
 ///
-/// This determines
-///   - `ethers_*` idents if `ethers-core`, `ethers-contract`, `ethers-providers`  are present in
-///     the manifest or the `ethers` is _not_ present
-///   - `ethers::*` otherwise
-///
-/// This process is a bit hacky, we run `cargo metadata` internally which
-/// resolves the current package but creates a new `Cargo.lock` file in the
-/// process. This is not a problem for regular workspaces but becomes an issue
-/// during publishing with `cargo publish` if the project does not ignore
-/// `Cargo.lock` in `.gitignore`, because then cargo can't proceed with
-/// publishing the crate because the created `Cargo.lock` leads to a modified
-/// workspace, not the `CARGO_MANIFEST_DIR` but the workspace `cargo publish`
-/// created in `./target/package/..`. Therefore we check prior to executing
-/// `cargo metadata` if a `Cargo.lock` file exists and delete it afterwards if
-/// it was created by `cargo metadata`.
-pub fn determine_ethers_crates() -> (&'static str, &'static str, &'static str) {
-    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR");
+/// Returns `None` on any error or if no dependencies are found.
+#[inline]
+fn crate_names_from_metadata(manifest_dir: PathBuf) -> Option<CrateNames> {
+    let metadata = MetadataCommand::new().current_dir(manifest_dir).exec().ok()?;
+    let pkg = metadata.root_package()?;
 
-    // if there is no cargo manifest, default to `ethers::`-style imports.
-    let manifest_dir = if let Ok(manifest_dir) = manifest_dir {
-        manifest_dir
-    } else {
-        return ("ethers::core", "ethers::contract", "ethers::providers")
-    };
-
-    // check if the lock file exists, if it's missing we need to clean up afterward
-    let lock_file = format!("{manifest_dir}/Cargo.lock");
-    let needs_lock_file_cleanup = !std::path::Path::new(&lock_file).exists();
-
-    let res = MetadataCommand::new()
-        .manifest_path(&format!("{manifest_dir}/Cargo.toml"))
-        .exec()
-        .ok()
-        .and_then(|metadata| {
-            metadata.root_package().and_then(|pkg| {
-                let sub_crates = Some(("ethers_core", "ethers_contract", "ethers_providers"));
-
-                // Note(mattsse): this is super hacky but required in order to compile and test
-                // ethers' internal crates
-                if [
+    // HACK(mattsse): this is required in order to compile and test ethers' internal crates
+    const INTERNAL_CRATES: [&str; 5] = [
         "ethers-contract",
         "ethers-derive-eip712",
         "ethers-signers",
         "ethers-middleware",
         "ethers-solc",
-                ]
-                .contains(&pkg.name.as_str())
-                {
-                    return sub_crates
+    ];
+    let pkg_name = pkg.name.as_str();
+    if INTERNAL_CRATES.contains(&pkg_name) {
+        return Some(SUB_CRATE_NAMES)
     }
 
     let mut has_ethers_core = false;
@@ -105,19 +101,8 @@ pub fn determine_ethers_crates() -> (&'static str, &'static str, &'static str) {
     }
 
     if has_ethers_core && has_ethers_contract && has_ethers_providers {
-                    return sub_crates
-                }
-
+        Some(SUB_CRATE_NAMES)
+    } else {
         None
-            })
-        })
-        .unwrap_or(("ethers::core", "ethers::contract", "ethers::providers"));
-
-    if needs_lock_file_cleanup {
-        // delete the `Cargo.lock` file that was created by `cargo metadata`
-        // if the package is not part of a workspace
-        let _ = std::fs::remove_file(lock_file);
     }
-
-    res
 }