Add .cairo-coverage-ignore (#109)

**Stack**:
- #111
- #110
- #109 ⬅
- #108

Cargo.toml

@@ -19,6 +19,7 @@ cairo-lang-sierra-to-casm = "2.8.2"
 cairo-lang-starknet-classes = "2.8.2"
 derived-deref = "2.1.0"
 itertools = "0.13.0"
+ignore = "0.4.23"
 serde = "1.0.215"
 serde_json = "1.0.133"
 snapbox = "0.6.20"

crates/cairo-coverage/Cargo.toml

@@ -13,6 +13,7 @@ cairo-lang-starknet-classes.workspace = true
 clap.workspace = true
 derived-deref.workspace = true
 itertools.workspace = true
+ignore.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 regex.workspace = true

crates/cairo-coverage/src/input/filter/ignore.rs

@@ -0,0 +1,49 @@
+use crate::input::filter::statement_category_filter::VIRTUAL_FILE_REGEX;
+use camino::{Utf8Path, Utf8PathBuf};
+use ignore::gitignore::Gitignore;
+use ignore::Match;
+
+const CAIRO_COVERAGE_IGNORE: &str = ".cairo-coverage-ignore";
+
+pub struct CairoCoverageIgnoreMatcher(Gitignore);
+
+impl CairoCoverageIgnoreMatcher {
+    /// Create a new instance of the [`CairoCoverageIgnoreMatcher`] that will be based on the [`CAIRO_COVERAGE_IGNORE`] file.
+    pub fn new(path: &Utf8Path) -> anyhow::Result<Self> {
+        let ignore_matcher = find_ignore_file(path)
+            .map(Gitignore::new)
+            .map(|(ignore, error)| {
+                if let Some(error) = error {
+                    Err(anyhow::Error::from(error))
+                } else {
+                    Ok(ignore)
+                }
+            })
+            .transpose()?
+            .unwrap_or_else(Gitignore::empty);
+
+        Ok(Self(ignore_matcher))
+    }
+
+    /// Check if the given path is ignored by the [`CAIRO_COVERAGE_IGNORE`] file.
+    pub fn is_ignored(&self, path: &str) -> bool {
+        let path: Utf8PathBuf = VIRTUAL_FILE_REGEX.replace_all(path, "").to_string().into();
+        let result = self.0.matched(&path, path.is_dir());
+        matches!(result, Match::Ignore(_))
+    }
+}
+
+/// Search for a [`CAIRO_COVERAGE_IGNORE`] file from the given directory and its parents until the root.
+fn find_ignore_file(start_dir: &Utf8Path) -> Option<Utf8PathBuf> {
+    let mut current_dir = Some(start_dir);
+
+    while let Some(dir) = current_dir {
+        let candidate = dir.join(CAIRO_COVERAGE_IGNORE);
+        if candidate.is_file() {
+            return Some(candidate);
+        }
+        current_dir = dir.parent();
+    }
+
+    None
+}

crates/cairo-coverage/src/input/filter/mod.rs

@@ -1 +1,2 @@
+mod ignore;
 pub mod statement_category_filter;

crates/cairo-coverage/src/input/filter/statement_category_filter.rs

@@ -1,5 +1,6 @@
 use crate::cli::IncludedComponent;
 use crate::data_loader::LoadedData;
+use crate::input::filter::ignore::CairoCoverageIgnoreMatcher;
 use crate::input::sierra_to_cairo_map::{SimpleLibfuncName, StatementOrigin};
 use cairo_annotations::annotations::coverage::SourceFileFullPath;
 use cairo_annotations::annotations::profiler::FunctionName;
@@ -48,6 +49,7 @@ enum StatementCategory {
     NonUserFunction,
     Macro,
     NotReliableLibfunc,
+    Ignored,
 }
 
 impl From<IncludedComponent> for StatementCategory {
@@ -63,6 +65,7 @@ pub struct StatementCategoryFilter {
     user_project_path: String,
     allowed_statement_categories: HashSet<StatementCategory>,
     test_functions: HashSet<String>,
+    ignore_matcher: CairoCoverageIgnoreMatcher,
 }
 
 impl StatementCategoryFilter {
@@ -87,12 +90,15 @@ impl StatementCategoryFilter {
             .chain(once(StatementCategory::UserFunction))
             .collect();
 
+        let ignore_matcher = CairoCoverageIgnoreMatcher::new(user_project_path)
+            .expect("Failed to create ignore matcher");
         let user_project_path = user_project_path.to_string();
 
         Self {
             user_project_path,
             allowed_statement_categories,
             test_functions,
+            ignore_matcher,
         }
     }
 
@@ -128,6 +134,10 @@ impl StatementCategoryFilter {
             labels.insert(StatementCategory::NotReliableLibfunc);
         }
 
+        if self.ignore_matcher.is_ignored(source_file_full_path) {
+            labels.insert(StatementCategory::Ignored);
+        }
+
         labels
     }
 }