feat(solc): revamped remapping auto detect

ethers-solc/src/compile.rs

@@ -42,6 +42,7 @@ use once_cell::sync::Lazy;
 use std::sync::Mutex;
 
 #[cfg(any(test, feature = "tests"))]
+#[allow(unused)]
 static LOCK: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
 
 #[cfg(all(feature = "svm", feature = "async"))]

ethers-solc/src/remappings.rs

@@ -1,6 +1,11 @@
 use crate::{error::SolcError, Result};
 use serde::{Deserialize, Serialize};
-use std::{fmt, str::FromStr};
+use std::{
+    collections::{hash_map::Entry, HashMap},
+    fmt,
+    path::{Path, PathBuf},
+    str::FromStr,
+};
 
 const DAPPTOOLS_CONTRACTS_DIR: &str = "src";
 const JS_CONTRACTS_DIR: &str = "contracts";
@@ -54,16 +59,14 @@ impl FromStr for Remapping {
     type Err = RemappingError;
 
     fn from_str(remapping: &str) -> std::result::Result<Self, Self::Err> {
-        let mut split = remapping.split('=');
-        let name = split.next().ok_or(RemappingError::NoPrefix)?.to_string();
-        if name.is_empty() {
+        let (name, path) = remapping.split_once('=').ok_or(RemappingError::NoPrefix)?;
+        if name.trim().is_empty() {
             return Err(RemappingError::NoPrefix)
         }
-        let path = split.next().ok_or(RemappingError::NoTarget)?.to_string();
-        if path.is_empty() {
+        if path.trim().is_empty() {
             return Err(RemappingError::NoTarget)
         }
-        Ok(Remapping { name, path })
+        Ok(Remapping { name: name.to_string(), path: path.to_string() })
     }
 }
 
@@ -176,6 +179,162 @@ impl Remapping {
 
         Ok(remappings)
     }
+
+    /// Attempts to autodetect all remappings given a certain root path.
+    ///
+    /// This will recursively scan all subdirectories of the root path, if a subdirectory contains a
+    /// solidity file then this a candidate for a remapping. The name of the remapping will be the
+    /// folder name.
+    ///
+    /// However, there are additional rules/assumptions when it comes to determining if a candidate
+    /// should in fact be a remapping:
+    ///
+    /// All names and paths end with a trailing "/"
+    ///
+    /// The name of the remapping will be the parent folder of a solidity file, unless the folder is
+    /// named `src`, `lib` or `contracts` in which case the name of the remapping will be the parent
+    /// folder's name of `src`, `lib`, `contracts`: The remapping of `repo1/src/contract.sol` is
+    /// `name: "repo1/", path: "repo1/src/"`
+    ///
+    /// Nested remappings need to be separated by `src`, `lib` or `contracts`, The remapping of
+    /// `repo1/lib/ds-math/src/contract.sol` is `name: "ds-match/", "repo1/lib/ds-math/src/"`
+    ///
+    /// Remapping detection is primarily designed for dapptool's rules for lib folders, however, we
+    /// attempt to detect and optimize various folder structures commonly used in `node_modules`
+    /// dependencies. For those the same rules apply. In addition, we try to unify all
+    /// remappings discovered according to the rules mentioned above, so that layouts like,
+    //   @aave/
+    //   ├─ governance/
+    //   │  ├─ contracts/
+    //   ├─ protocol-v2/
+    //   │  ├─ contracts/
+    ///
+    /// which would be multiple rededications according to our rules ("governance", "protocol-v2"), are unified into `@aave` by looking at their common ancestor, the root of this subdirectory (`@aavee`)
+    pub fn find_all(root: impl AsRef<Path>) -> Vec<Remapping> {
+        /// prioritize ("a", "1/2") over ("a", "1/2/3")
+        fn insert_higher_path(mappings: &mut HashMap<String, PathBuf>, key: String, path: PathBuf) {
+            match mappings.entry(key) {
+                Entry::Occupied(mut e) => {
+                    if e.get().components().count() > path.components().count() {
+                        e.insert(path);
+                    }
+                }
+                Entry::Vacant(e) => {
+                    e.insert(path);
+                }
+            }
+        }
+
+        let mut remappings = HashMap::new();
+        // iterate over all dirs that are children of the root
+        for dir in walkdir::WalkDir::new(root)
+            .follow_links(true)
+            .min_depth(1)
+            .max_depth(1)
+            .into_iter()
+            .filter_map(std::result::Result::ok)
+            .filter(|e| e.file_type().is_dir())
+        {
+            let dir_path = dir.path();
+
+            // in node_modules there could be following pattern:
+            //   @aave/
+            //   ├─ governance/
+            //   │  ├─ contracts/
+            //   ├─ protocol-v2/
+            //   │  ├─ contracts/
+            // in such cases, the desired remapping name would be `@aave`, but at this point we
+            // would have detected `governance` and `protocol-v2` as remapping names. so
+            // now we need to unify them by checking if they share the `dir_path` as
+            // common ancestor. We make the assumption here, that we can only unify
+            // remappings if their direct parent dir is the root, so `@aave/lib` or
+            // `@aave/src` is not mergeable as that would violate dapptools style lib paths and
+            // remappings. This means we can only unify/simplify them if there is no! `src` or `lib`
+            // path between the remappings' path and the dir_path
+            if let Some(root_name) = dir_path.file_name().and_then(|f| f.to_str()) {
+                let mut simplified = false;
+                // check all remappings in this depth 1 folder
+                'outer: for (name, path) in scan_children(dir_path) {
+                    let mut p = path.as_path();
+                    let mut first_parent = true;
+                    while let Some(parent) = p.parent() {
+                        if parent == dir_path {
+                            if !simplified {
+                                // handle trailing src,lib,contracts dir in cases like
+                                // `dir_path/@ens/contracts`
+                                let path = if first_parent { path } else { dir_path.to_path_buf() };
+                                insert_higher_path(
+                                    &mut remappings,
+                                    format!("{}/", root_name),
+                                    path,
+                                );
+                                simplified = true;
+                            }
+                            continue 'outer
+                        }
+                        if parent.ends_with("src") || parent.ends_with("lib") {
+                            // end early
+                            insert_higher_path(&mut remappings, name, path);
+                            continue 'outer
+                        }
+                        first_parent = false;
+                        p = parent;
+                    }
+                }
+            }
+        }
+        remappings
+            .into_iter()
+            .map(|(name, path)| Remapping { name, path: format!("{}/", path.display()) })
+            .collect()
+    }
+}
+
+/// Recursively scans sub folders and checks if they contain a solidity file
+fn scan_children(root: &Path) -> HashMap<String, PathBuf> {
+    // this is a marker if the current root is already a remapping
+    let mut remapping = false;
+
+    // all found remappings
+    let mut remappings = HashMap::new();
+
+    for entry in walkdir::WalkDir::new(&root)
+        .min_depth(1)
+        .max_depth(1)
+        .into_iter()
+        .filter_map(std::result::Result::ok)
+    {
+        let entry: walkdir::DirEntry = entry;
+
+        if entry.file_type().is_file() && !remapping {
+            if entry.file_name().to_str().filter(|f| f.ends_with(".sol")).is_some() {
+                // found a solidity file
+
+                // this will hold the actual root remapping if root is named `src` or `lib`
+                let actual_parent = root.parent().filter(|_| {
+                    root.ends_with("src") || root.ends_with("lib") || root.ends_with("contracts")
+                });
+
+                let parent = actual_parent.unwrap_or(root);
+                if let Some(name) = parent.file_name().and_then(|f| f.to_str()) {
+                    remappings.insert(format!("{}/", name), root.to_path_buf());
+                    remapping = true;
+                }
+            }
+        } else if entry.file_type().is_dir() {
+            let path = entry.path();
+            // we skip `tests` and nested `node_modules`
+            if !path.ends_with("tests") || !path.ends_with("node_modules") {
+                for (name, path) in scan_children(path) {
+                    if let Entry::Vacant(e) = remappings.entry(name) {
+                        e.insert(path);
+                    }
+                }
+            }
+        }
+    }
+
+    remappings
 }
 
 #[cfg(test)]
@@ -254,7 +413,7 @@ mod tests {
         mkdir_or_touch(tmp_dir_path, &paths[..]);
 
         let path = tmp_dir_path.display().to_string();
-        let mut remappings = Remapping::find_many(&path).unwrap();
+        let mut remappings = Remapping::find_all(&path);
         remappings.sort_unstable();
 
         let mut expected = vec![
@@ -302,7 +461,7 @@ mod tests {
         touch(&contract2).unwrap();
 
         let path = tmp_dir.path().display().to_string();
-        let mut remappings = Remapping::find_many(&path).unwrap();
+        let mut remappings = Remapping::find_all(&path);
         remappings.sort_unstable();
         let mut expected = vec![
             Remapping {
@@ -317,4 +476,36 @@ mod tests {
         expected.sort_unstable();
         assert_eq!(remappings, expected);
     }
+
+    #[test]
+    fn hardhat_remappings() {
+        let tmp_dir = tempdir::TempDir::new("node_modules").unwrap();
+        let tmp_dir_node_modules = tmp_dir.path().join("node_modules");
+        let paths = [
+            "node_modules/@aave/aave-token/contracts/token/",
+            "node_modules/@aave/aave-token/contracts/token/AaveToken.sol",
+            "node_modules/@aave/governance-v2/contracts/governance/",
+            "node_modules/@aave/governance-v2/contracts/governance/Executor.sol",
+            "node_modules/@aave/protocol-v2/contracts/protocol/lendingpool/",
+            "node_modules/@aave/protocol-v2/contracts/protocol/lendingpool/LendingPool.sol",
+            "node_modules/@ensdomains/ens/contracts/",
+            "node_modules/@ensdomains/ens/contracts/contract.sol",
+        ];
+        mkdir_or_touch(tmp_dir.path(), &paths[..]);
+        let mut remappings = Remapping::find_all(&tmp_dir_node_modules);
+        remappings.sort_unstable();
+        let mut expected = vec![
+            Remapping {
+                name: "@aave/".to_string(),
+                path: to_str(tmp_dir_node_modules.join("@aave")),
+            },
+            Remapping {
+                name: "@ensdomains/".to_string(),
+                path: to_str(tmp_dir_node_modules.join("@ensdomains")),
+            },
+        ];
+        expected.sort_unstable();
+
+        assert_eq!(remappings, expected);
+    }
 }