Merge fix/m20-append-lines-error-handling: fix append_lines I/O error swallowing (closes #45) + clippy cleanup

crates/bench/src/data_gen.rs

@@ -83,11 +83,11 @@ pub fn generate_growable_file(dir: &Path) -> std::io::Result<PathBuf> {
 
 /// Append `count` lines to the file
 pub fn append_lines(path: &Path, count: usize) -> std::io::Result<()> {
+    let existing_lines = count_existing_lines(path)?;
     let mut file = BufWriter::with_capacity(
         64 * 1024,
         fs::OpenOptions::new().append(true).open(path)?,
     );
-    let existing_lines = count_existing_lines(path).unwrap_or(0);
     for i in 0..count {
         writeln!(
             file,
@@ -117,7 +117,12 @@ pub fn rotate_file(path: &Path) -> std::io::Result<PathBuf> {
 fn count_existing_lines(path: &Path) -> std::io::Result<u64> {
     let file = fs::File::open(path)?;
     let reader = BufReader::new(file);
-    Ok(reader.lines().count() as u64)
+    let mut count = 0u64;
+    for line in reader.lines() {
+        line?;
+        count += 1;
+    }
+    Ok(count)
 }
 
 #[cfg(test)]

crates/bench/src/mmap_reader.rs

@@ -35,7 +35,7 @@ const HANDLER_NONE: u8 = 0;
 const HANDLER_DEFAULT: u8 = 1;
 const HANDLER_IGNORE: u8 = 2;
 const HANDLER_PLAIN: u8 = 3; // extern "C" fn(c_int)
-#[expect(clippy::unseparated_literal_suffix, reason = "clarity: this is the SA_SIGACTION variant")]
+#[allow(clippy::unseparated_literal_suffix, reason = "clarity: this is the SA_SIGACTION variant")]
 const HANDLER_SIGACTION: u8 = 4; // extern "C" fn(c_int, *mut siginfo_t, *mut c_void)
 
 /// Old SIGBUS handler type — raw atomic, async-signal-safe to read.

crates/bench/src/report.rs

@@ -143,8 +143,7 @@ pub fn format_report(results: &[BenchmarkResult]) -> String {
             report.push_str("| Test | Variant | RSS | Peak RSS | Page Faults |\n");
             report.push_str("|------|---------|-----|----------|-------------|\n");
 
-            let mut mem_rows: Vec<&BenchmarkResult> =
-                category_results.iter().copied().collect();
+            let mut mem_rows: Vec<&BenchmarkResult> = category_results.to_vec();
             mem_rows.sort_by(|a, b| {
                 (&a.test_name, &a.backend, &a.variant)
                     .cmp(&(&b.test_name, &b.backend, &b.variant))
@@ -163,7 +162,10 @@ pub fn format_report(results: &[BenchmarkResult]) -> String {
             report.push('\n');
         }
 
-        let mut extras: Vec<(String, String, Vec<(String, f64)>)> = category_results
+        type ExtraEntry = (String, f64);
+        type ExtraGroup = (String, String, Vec<ExtraEntry>);
+
+        let mut extras: Vec<ExtraGroup> = category_results
             .iter()
             .filter(|r| !r.extra.is_empty())
             .map(|r| {