From 030488eca5d4fe4b5afaa71abdabff16013cea7a Mon Sep 17 00:00:00 2001
From: Matthias Seitz <matthias.seitz@outlook.de>
Date: Thu, 2 Jun 2022 19:31:02 +0200
Subject: [PATCH] fix(solc): invalidate cache on unresolve error (#1337)

---
 ethers-solc/src/cache.rs        | 19 +++++++++++---
 ethers-solc/src/resolver/mod.rs | 13 ++++++++--
 ethers-solc/tests/project.rs    | 45 ++++++++++++++++++++++++++++++++-
 3 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/ethers-solc/src/cache.rs b/ethers-solc/src/cache.rs
index 087c38de..4e837bda 100644
--- a/ethers-solc/src/cache.rs
+++ b/ethers-solc/src/cache.rs
@@ -781,12 +781,17 @@ pub(crate) enum ArtifactsCache<'a, T: ArtifactOutput> {
 
 impl<'a, T: ArtifactOutput> ArtifactsCache<'a, T> {
     pub fn new(project: &'a Project<T>, edges: GraphEdges) -> Result<Self> {
-        /// returns the [SolFilesCache] to use
-        fn get_cache<T: ArtifactOutput>(project: &Project<T>) -> SolFilesCache {
+        /// Returns the [SolFilesCache] to use
+        ///
+        /// Returns a new empty cache if the cache does not exist or `invalidate_cache` is set.
+        fn get_cache<T: ArtifactOutput>(
+            project: &Project<T>,
+            invalidate_cache: bool,
+        ) -> SolFilesCache {
             // the currently configured paths
             let paths = project.paths.paths_relative();
 
-            if project.cache_path().exists() {
+            if !invalidate_cache && project.cache_path().exists() {
                 if let Ok(cache) = SolFilesCache::read_joined(&project.paths) {
                     if cache.paths == paths {
                         // unchanged project paths
@@ -794,13 +799,19 @@ impl<'a, T: ArtifactOutput> ArtifactsCache<'a, T> {
                     }
                 }
             }
+
             // new empty cache
             SolFilesCache::new(Default::default(), paths)
         }
 
         let cache = if project.cached {
+            // we only read the existing cache if we were able to resolve the entire graph
+            // if we failed to resolve an import we invalidate the cache so don't get any false
+            // positives
+            let invalidate_cache = !edges.unresolved_imports().is_empty();
+
             // read the cache file if it already exists
-            let mut cache = get_cache(project);
+            let mut cache = get_cache(project, invalidate_cache);
 
             cache.remove_missing_files();
 
diff --git a/ethers-solc/src/resolver/mod.rs b/ethers-solc/src/resolver/mod.rs
index 15fb77fb..571e3602 100644
--- a/ethers-solc/src/resolver/mod.rs
+++ b/ethers-solc/src/resolver/mod.rs
@@ -88,6 +88,8 @@ pub struct GraphEdges {
     /// Combined with the `indices` this way we can determine if a file was original added to the
     /// graph as input or was added as resolved import, see [`Self::is_input_file()`]
     num_input_files: usize,
+    /// tracks all imports that we failed to resolve
+    unresolved_imports: HashSet<PathBuf>,
 }
 
 impl GraphEdges {
@@ -111,6 +113,11 @@ impl GraphEdges {
         self.files().skip(self.num_input_files)
     }
 
+    /// Returns all imports that we failed to resolve
+    pub fn unresolved_imports(&self) -> &HashSet<PathBuf> {
+        &self.unresolved_imports
+    }
+
     /// 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]
@@ -277,6 +284,7 @@ impl Graph {
         self.nodes.iter().take(self.edges.num_input_files)
     }
 
+    /// Returns all files imported by the given file
     pub fn imports(&self, path: impl AsRef<Path>) -> HashSet<&PathBuf> {
         self.edges.imports(path)
     }
@@ -327,7 +335,7 @@ impl Graph {
 
         // keep track of all unique paths that we failed to resolve to not spam the reporter with
         // the same path
-        let mut unresolved_paths = HashSet::new();
+        let mut unresolved_imports = HashSet::new();
 
         // now we need to resolve all imports for the source file and those imported from other
         // locations
@@ -346,7 +354,7 @@ impl Graph {
                         add_node(&mut unresolved, &mut index, &mut resolved_imports, import)?;
                     }
                     Err(err) => {
-                        if unresolved_paths.insert(import_path.to_path_buf()) {
+                        if unresolved_imports.insert(import_path.to_path_buf()) {
                             crate::report::unresolved_import(import_path, &paths.remappings);
                         }
                         tracing::trace!(
@@ -372,6 +380,7 @@ impl Graph {
                 .map(|(idx, node)| (idx, node.data.version_req.clone()))
                 .collect(),
             data: Default::default(),
+            unresolved_imports,
         };
         Ok(Graph { nodes, edges, root: paths.root.clone() })
     }
diff --git a/ethers-solc/tests/project.rs b/ethers-solc/tests/project.rs
index 5aaad5aa..8d4b1b30 100644
--- a/ethers-solc/tests/project.rs
+++ b/ethers-solc/tests/project.rs
@@ -2,7 +2,7 @@
 
 use std::{
     collections::{BTreeMap, HashMap, HashSet},
-    io,
+    fs, io,
     path::{Path, PathBuf},
     str::FromStr,
 };
@@ -1768,3 +1768,46 @@ contract D { }
         cache.files.keys().cloned().collect::<Vec<_>>()
     );
 }
+
+#[test]
+fn test_failure_after_removing_file() {
+    let project = TempProject::dapptools().unwrap();
+    project
+        .add_source(
+            "A",
+            r#"
+pragma solidity ^0.8.10;
+import "./B.sol";
+contract A { }
+"#,
+        )
+        .unwrap();
+
+    project
+        .add_source(
+            "B",
+            r#"
+pragma solidity ^0.8.10;
+import "./C.sol";
+contract B { }
+"#,
+        )
+        .unwrap();
+
+    let c = project
+        .add_source(
+            "C",
+            r#"
+pragma solidity ^0.8.10;
+contract C { }
+"#,
+        )
+        .unwrap();
+
+    let compiled = project.compile().unwrap();
+    assert!(!compiled.has_compiler_errors());
+
+    fs::remove_file(c).unwrap();
+    let compiled = project.compile().unwrap();
+    assert!(compiled.has_compiler_errors());
+}