ethers-rs/ethers-solc/src/resolver.rs

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//! Resolution of the entire dependency graph for a project.
//!
//! This module implements the core logic in taking all contracts of a project and creating a
//! resolved graph with applied remappings for all source contracts.
//!
//! Some constraints we're working with when resolving contracts
//!
//! 1. Each file can contain several source units and can have any number of imports/dependencies
//! (using the term interchangeably). Each dependency can declare a version range that it is
//! compatible with, solidity version pragma.
//! 2. A dependency can be imported from any directory,
//! see `Remappings`
//!
//! Finding all dependencies is fairly simple, we're simply doing a DFS, starting the source
//! contracts
//!
//! ## Performance
//!
//! Note that this is a relatively performance-critical portion of the ethers-solc preprocessing.
//! The data that needs to be processed is proportional to the size of the dependency
//! graph, which can, depending on the project, often be quite large.
//!
//! Note that, unlike the solidity compiler, we work with the filesystem, where we have to resolve
//! remappings and follow relative paths. We're also limiting the nodes in the graph to solidity
//! files, since we're only interested in their
//! [version pragma](https://docs.soliditylang.org/en/develop/layout-of-source-files.html#version-pragma),
//! which is defined on a per source file basis.
use std::{
collections::{HashMap, VecDeque},
path::{Path, PathBuf},
};
use rayon::prelude::*;
use semver::VersionReq;
use solang_parser::pt::{Import, SourceUnitPart};
use crate::{error::Result, utils, ProjectPathsConfig, Solc, Source, Sources};
/// Represents a fully-resolved solidity dependency graph. Each node in the graph
/// is a file and edges represent dependencies between them.
/// See also https://docs.soliditylang.org/en/latest/layout-of-source-files.html?highlight=import#importing-other-source-files
#[derive(Debug)]
pub struct Graph {
nodes: Vec<Node>,
/// The indices of `edges` correspond to the `nodes`. That is, `edges[0]`
/// is the set of outgoing edges for `nodes[0]`.
edges: Vec<Vec<usize>>,
/// index maps for a solidity file to an index, for fast lookup.
indices: HashMap<PathBuf, usize>,
/// with how many input files we started with, corresponds to `let input_files =
/// nodes[..num_input_files]`.
num_input_files: usize,
/// the root of the project this graph represents
#[allow(unused)]
root: PathBuf,
}
impl Graph {
/// Returns a list of nodes the given node index points to for the given kind.
pub fn imported_nodes(&self, from: usize) -> &[usize] {
&self.edges[from]
}
/// Returns all the resolved files and their index in the graph
pub fn files(&self) -> &HashMap<PathBuf, usize> {
&self.indices
}
/// Gets a node by index.
pub fn node(&self, index: usize) -> &Node {
&self.nodes[index]
}
/// Returns all files together with their paths
pub fn into_sources(self) -> Sources {
self.nodes.into_iter().map(|node| (node.path, node.source)).collect()
}
/// Returns an iterator that yields only those nodes that represent input files.
/// See `Self::resolve_sources`
/// This won't yield any resolved library nodes
pub fn input_nodes(&self) -> impl Iterator<Item = &Node> {
self.nodes.iter().take(self.num_input_files)
}
/// Resolves a number of sources within the given config
pub fn resolve_sources(paths: &ProjectPathsConfig, sources: Sources) -> Result<Graph> {
/// checks if the given target path was already resolved, if so it adds its id to the list
/// of resolved imports. If it hasn't been resolved yet, it queues in the file for
/// processing
fn add_node(
unresolved: &mut VecDeque<(PathBuf, Node)>,
index: &mut HashMap<PathBuf, usize>,
resolved_imports: &mut Vec<usize>,
target: PathBuf,
) -> Result<()> {
if let Some(idx) = index.get(&target).copied() {
resolved_imports.push(idx);
} else {
// imported file is not part of the input files
let node = read_node(&target)?;
unresolved.push_back((target.clone(), node));
let idx = index.len();
index.insert(target, idx);
resolved_imports.push(idx);
}
Ok(())
}
// we start off by reading all input files, which includes all solidity files from the
// source and test folder
let mut unresolved: VecDeque<(PathBuf, Node)> = sources
.into_par_iter()
.map(|(path, source)| {
let data = parse_data(source.as_ref());
(path.clone(), Node { path, source, data })
})
.collect();
// identifiers of all resolved files
let mut index: HashMap<_, _> =
unresolved.iter().enumerate().map(|(idx, (p, _))| (p.clone(), idx)).collect();
let num_input_files = unresolved.len();
// contains the files and their dependencies
let mut nodes = Vec::with_capacity(unresolved.len());
let mut edges = Vec::with_capacity(unresolved.len());
// now we need to resolve all imports for the source file and those imported from other
// locations
while let Some((path, node)) = unresolved.pop_front() {
let mut resolved_imports = Vec::with_capacity(node.data.imports.len());
// parent directory of the current file
let cwd = match path.parent() {
Some(inner) => inner,
None => continue,
};
for import in node.data.imports.iter() {
match paths.resolve_import(cwd, import) {
Ok(import) => {
add_node(&mut unresolved, &mut index, &mut resolved_imports, import)?;
}
Err(err) => {
tracing::trace!("{}", err)
}
}
}
nodes.push(node);
edges.push(resolved_imports);
}
Ok(Graph { nodes, edges, indices: index, num_input_files, root: paths.root.clone() })
}
/// Resolves the dependencies of a project's source contracts
pub fn resolve(paths: &ProjectPathsConfig) -> Result<Graph> {
Self::resolve_sources(paths, paths.read_input_files()?)
}
}
#[cfg(all(feature = "svm", feature = "async"))]
impl Graph {
/// Returns all input files together with their appropriate version.
///
/// First we determine the compatible version for each input file (from sources and test folder,
/// see `Self::resolve`) and then we add all resolved library imports.
pub fn into_sources_by_version(self, offline: bool) -> Result<VersionedSources> {
/// insert the imports of the given node into the sources map
/// There can be following graph:
/// `A(<=0.8.10) imports C(>0.4.0)` and `B(0.8.11) imports C(>0.4.0)`
/// where `C` is a library import, in which case we assign `C` only to the first input file.
/// However, it's not required to include them in the solc `CompilerInput` as they would get
/// picked up by solc otherwise, but we add them, so we can create a corresponding
/// cache entry for them as well. This can be optimized however
fn insert_imports(
idx: usize,
all_nodes: &mut HashMap<usize, Node>,
sources: &mut Sources,
edges: &[Vec<usize>],
num_input_files: usize,
) {
for dep in edges[idx].iter().copied() {
// we only process nodes that were added as part of the resolve step because input
// nodes are handled separately
if dep >= num_input_files {
// library import
if let Some(node) = all_nodes.remove(&dep) {
sources.insert(node.path, node.source);
insert_imports(dep, all_nodes, sources, edges, num_input_files);
}
}
}
}
let versioned_nodes = self.get_input_node_versions(offline)?;
let Self { nodes, edges, num_input_files, .. } = self;
let mut versioned_sources = HashMap::with_capacity(versioned_nodes.len());
let mut all_nodes = nodes.into_iter().enumerate().collect::<HashMap<_, _>>();
// determine the `Sources` set for each solc version
for (version, input_node_indices) in versioned_nodes {
let mut sources = Sources::new();
// we only process input nodes (from sources, tests for example)
for idx in input_node_indices {
// insert the input node in the sources set and remove it from the available set
let node = all_nodes.remove(&idx).expect("node is preset. qed");
sources.insert(node.path, node.source);
insert_imports(idx, &mut all_nodes, &mut sources, &edges, num_input_files);
}
versioned_sources.insert(version, sources);
}
Ok(VersionedSources { inner: versioned_sources, offline })
}
/// Writes the list of imported files into the given formatter:
/// `A (version) imports B (version)`
fn format_imports_list<W: std::fmt::Write>(
&self,
idx: usize,
f: &mut W,
) -> std::result::Result<(), std::fmt::Error> {
let node = self.node(idx);
for dep in self.imported_nodes(idx) {
let dep = self.node(*dep);
writeln!(
f,
" {} ({:?}) imports {} ({:?})",
utils::source_name(&node.path, &self.root).display(),
node.data.version,
utils::source_name(&dep.path, &self.root).display(),
dep.data.version
)?;
}
for dep in self.imported_nodes(idx) {
self.format_imports_list(*dep, f)?;
}
Ok(())
}
/// Filters incompatible versions from the `candidates`.
fn retain_compatible_versions(
&self,
idx: usize,
candidates: &mut Vec<&crate::SolcVersion>,
traversed: &mut std::collections::HashSet<(usize, usize)>,
) -> std::result::Result<(), String> {
let node = self.node(idx);
if let Some(ref req) = node.data.version_req {
candidates.retain(|v| req.matches(v.as_ref()));
}
for dep in self.imported_nodes(idx).iter().copied() {
// check for circular deps which would result in endless recursion SO here
// a circular dependency exists, if there was already a `dependency imports current
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// node` relationship in the traversed path we skip this node
traversed.insert((idx, dep));
if traversed.contains(&(dep, idx)) {
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tracing::warn!(
"Detected cyclic imports {} <-> {}",
utils::source_name(&self.nodes[idx].path, &self.root).display(),
utils::source_name(&self.nodes[dep].path, &self.root).display()
);
continue
}
self.retain_compatible_versions(dep, candidates, traversed)?;
}
Ok(())
}
/// Ensures that all files are compatible with all of their imports.
pub fn ensure_compatible_imports(&self, offline: bool) -> Result<()> {
self.get_input_node_versions(offline)?;
Ok(())
}
/// Returns a map of versions together with the input nodes that are compatible with that
/// version.
///
/// This will essentially do a DFS on all input sources and their transitive imports and
/// checking that all can compiled with the version stated in the input file.
///
/// Returns an error message with __all__ input files that don't have compatible imports.
///
/// This also attempts to prefer local installations over remote available.
/// If `offline` is set to `true` then only already installed.
fn get_input_node_versions(
&self,
offline: bool,
) -> Result<HashMap<crate::SolcVersion, Vec<usize>>> {
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tracing::trace!("resolving input node versions");
// this is likely called by an application and will be eventually printed so we don't exit
// on first error, instead gather all the errors and return a bundled error message instead
let mut errors = Vec::new();
// we also don't want duplicate error diagnostic
let mut erroneous_nodes = std::collections::HashSet::with_capacity(self.num_input_files);
let all_versions = if offline { Solc::installed_versions() } else { Solc::all_versions() };
// stores all versions and their nodes
let mut versioned_nodes = HashMap::new();
// walking through the node's dep tree and filtering the versions along the way
for idx in 0..self.num_input_files {
let mut candidates = all_versions.iter().collect::<Vec<_>>();
let mut traveresd = std::collections::HashSet::new();
if let Err(msg) = self.retain_compatible_versions(idx, &mut candidates, &mut traveresd)
{
errors.push(msg);
}
if candidates.is_empty() && !erroneous_nodes.contains(&idx) {
let mut msg = String::new();
self.format_imports_list(idx, &mut msg).unwrap();
errors.push(format!(
"Discovered incompatible solidity versions in following\n: {}",
msg
));
erroneous_nodes.insert(idx);
} else {
let candidate = (*candidates
.iter()
.rev()
.find(|v| v.is_installed())
.or_else(|| candidates.iter().last())
.unwrap())
.clone();
versioned_nodes.entry(candidate).or_insert_with(|| Vec::with_capacity(1)).push(idx);
}
}
if errors.is_empty() {
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tracing::trace!(
"resolved {} versions {:?}",
versioned_nodes.len(),
versioned_nodes.keys()
);
Ok(versioned_nodes)
} else {
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tracing::error!("failed to resolve versions");
Err(crate::error::SolcError::msg(errors.join("\n")))
}
}
}
/// Container type for solc versions and their compatible sources
#[cfg(all(feature = "svm", feature = "async"))]
#[derive(Debug)]
pub struct VersionedSources {
inner: HashMap<crate::SolcVersion, Sources>,
offline: bool,
}
#[cfg(all(feature = "svm", feature = "async"))]
impl VersionedSources {
/// Resolves or installs the corresponding `Solc` installation.
pub fn get(
self,
allowed_lib_paths: &crate::AllowedLibPaths,
) -> Result<std::collections::BTreeMap<Solc, Sources>> {
use crate::SolcError;
let mut sources_by_version = std::collections::BTreeMap::new();
for (version, sources) in self.inner {
if !version.is_installed() {
if self.offline {
return Err(SolcError::msg(format!(
"missing solc \"{}\" installation in offline mode",
version
)))
} else {
Solc::blocking_install(version.as_ref())?;
}
}
let solc = Solc::find_svm_installed_version(version.to_string())?.ok_or_else(|| {
SolcError::msg(format!("solc \"{}\" should have been installed", version))
})?;
tracing::trace!("verifying solc checksum for {}", solc.solc.display());
if solc.verify_checksum().is_err() {
tracing::trace!("corrupted solc version, redownloading \"{}\"", version);
Solc::blocking_install(version.as_ref())?;
tracing::trace!("reinstalled solc: \"{}\"", version);
}
sources_by_version
.insert(solc.arg("--allow-paths").arg(allowed_lib_paths.to_string()), sources);
}
Ok(sources_by_version)
}
}
#[derive(Debug)]
pub struct Node {
path: PathBuf,
source: Source,
data: SolData,
}
#[derive(Debug, Clone)]
#[allow(unused)]
struct SolData {
version: Option<String>,
version_req: Option<VersionReq>,
imports: Vec<PathBuf>,
}
fn read_node(file: impl AsRef<Path>) -> Result<Node> {
let file = file.as_ref();
let source = Source::read(file)?;
let data = parse_data(source.as_ref());
Ok(Node { path: file.to_path_buf(), source, data })
}
/// Extracts the useful data from a solidity source
///
/// This will attempt to parse the solidity AST and extract the imports and version pragma. If
/// parsing fails, we'll fall back to extract that info via regex
fn parse_data(content: &str) -> SolData {
let mut version = None;
let mut imports = Vec::new();
match solang_parser::parse(content, 0) {
Ok(units) => {
for unit in units.0 {
match unit {
SourceUnitPart::PragmaDirective(_, _, pragma, value) => {
if pragma.name == "solidity" {
// we're only interested in the solidity version pragma
version = Some(value.string);
}
}
SourceUnitPart::ImportDirective(_, import) => {
let import = match import {
Import::Plain(s, _) => s,
Import::GlobalSymbol(s, _, _) => s,
Import::Rename(s, _, _) => s,
};
imports.push(PathBuf::from(import.string));
}
_ => {}
}
}
}
Err(err) => {
tracing::trace!(
"failed to parse solidity ast: \"{:?}\". Falling back to regex to extract data",
err
);
version = utils::find_version_pragma(content).map(str::to_string);
imports = utils::find_import_paths(content)
.into_iter()
.map(|p| Path::new(p).to_path_buf())
.collect()
}
};
let version_req = if let Some(ref v) = version { Solc::version_req(v).ok() } else { None };
SolData { version_req, version, imports }
}
#[cfg(test)]
mod tests {
use super::*;
use std::path::Path;
#[test]
fn can_resolve_hardhat_dependency_graph() {
let root = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("test-data/hardhat-sample");
let paths = ProjectPathsConfig::hardhat(root).unwrap();
let graph = Graph::resolve(&paths).unwrap();
assert_eq!(graph.num_input_files, 1);
assert_eq!(graph.files().len(), 2);
assert_eq!(
graph.files().clone(),
HashMap::from([
(paths.sources.join("Greeter.sol"), 0),
(paths.root.join("node_modules/hardhat/console.sol"), 1),
])
);
}
#[test]
fn can_resolve_dapp_dependency_graph() {
let root = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("test-data/dapp-sample");
let paths = ProjectPathsConfig::dapptools(root).unwrap();
let graph = Graph::resolve(&paths).unwrap();
assert_eq!(graph.num_input_files, 2);
assert_eq!(graph.files().len(), 3);
assert_eq!(
graph.files().clone(),
HashMap::from([
(paths.sources.join("Dapp.sol"), 0),
(paths.sources.join("Dapp.t.sol"), 1),
(paths.root.join("lib/ds-test/src/test.sol"), 2),
])
);
let dapp_test = graph.node(1);
assert_eq!(dapp_test.path, paths.sources.join("Dapp.t.sol"));
assert_eq!(
dapp_test.data.imports,
vec![
Path::new("ds-test/test.sol").to_path_buf(),
Path::new("./Dapp.sol").to_path_buf()
]
);
assert_eq!(graph.imported_nodes(1).to_vec(), vec![2, 0]);
}
}