feat: use cached artifacts if solc config is almost the same

src/artifacts/output_selection.rs

@@ -119,6 +119,19 @@ impl OutputSelection {
     pub fn empty_file_output_select() -> FileOutputSelection {
         Default::default()
     }
+
+    /// Returns true if this output selection is a subset of the other output selection.
+    pub fn is_subset_of(&self, other: &Self) -> bool {
+        self.0.iter().all(|(file, selection)| {
+            other.0.get(file).map_or(false, |other_selection| {
+                selection.iter().all(|(contract, outputs)| {
+                    other_selection.get(contract).map_or(false, |other_outputs| {
+                        outputs.iter().all(|output| other_outputs.contains(output))
+                    })
+                })
+            })
+        })
+    }
 }
 
 // this will make sure that if the `FileOutputSelection` for a certain file is empty will be

src/cache.rs

@@ -776,8 +776,8 @@ impl<'a, T: ArtifactOutput> ArtifactsCacheInner<'a, T> {
             return true;
         }
 
-        if self.project.solc_config != entry.solc_config {
-            trace!("solc config changed");
+        if !self.project.solc_config.can_use_cached(&entry.solc_config) {
+            trace!("solc config not compatible");
             return true;
         }
 

src/config.rs

@@ -771,6 +771,38 @@ impl SolcConfig {
     pub fn builder() -> SolcConfigBuilder {
         SolcConfigBuilder::default()
     }
+
+    /// Returns true if artifacts compiled with given `cached` config are compatible with this
+    /// config and if compilation can be skipped.
+    ///
+    /// Ensures that all settings fields are equal except for `output_selection` which is required
+    /// to be a subset of `cached.output_selection`.
+    pub fn can_use_cached(&self, cached: &SolcConfig) -> bool {
+        let SolcConfig { settings } = self;
+        let Settings {
+            stop_after,
+            remappings,
+            optimizer,
+            model_checker,
+            metadata,
+            output_selection,
+            evm_version,
+            via_ir,
+            debug,
+            libraries,
+        } = settings;
+
+        *stop_after == cached.settings.stop_after
+            && *remappings == cached.settings.remappings
+            && *optimizer == cached.settings.optimizer
+            && *model_checker == cached.settings.model_checker
+            && *metadata == cached.settings.metadata
+            && *evm_version == cached.settings.evm_version
+            && *via_ir == cached.settings.via_ir
+            && *debug == cached.settings.debug
+            && *libraries == cached.settings.libraries
+            && output_selection.is_subset_of(&cached.settings.output_selection)
+    }
 }
 
 impl From<SolcConfig> for Settings {