XXX: debugging

Author: nnethercote

src/tools/tidy/src/alphabetical.rs

@@ -36,14 +36,19 @@ const END_MARKER: &str = "tidy-alphabetical-end";
 
 fn check_section<'a>(
     file: impl Display,
-    lines: impl Iterator<Item = (usize, &'a str)>,
+    mut lines: impl Iterator<Item = (usize, &'a str)>,
     bad: &mut bool,
 ) {
     let mut prev_line = String::new();
     let mut first_indent = None;
     let mut in_split_line = None;
+    let mut pm1 = None;
+    let mut pm2 = None;
+    let mut pm3 = None;
+
+    loop {
+        let Some((line_idx, line)) = lines.next() else { break };
 
-    for (line_idx, line) in lines {
         if line.is_empty() {
             continue;
         }
@@ -91,9 +96,20 @@ fn check_section<'a>(
 
         if trimmed_line.to_lowercase() < prev_line_trimmed_lowercase {
             tidy_error!(bad, "{file}:{}: line not in alphabetical order", line_idx + 1,);
+            tidy_error!(bad, "{file}: line-3: `{:?}", pm3);
+            tidy_error!(bad, "{file}: line-2: `{:?}", pm2);
+            tidy_error!(bad, "{file}: line-1: `{:?}", pm1);
+            tidy_error!(bad, "{file}: line0: `{}", line);
+            tidy_error!(bad, "{file}: line1: `{:?}", lines.next());
+            tidy_error!(bad, "{file}: line2: `{:?}", lines.next());
+            tidy_error!(bad, "{file}: line3: `{:?}", lines.next());
         }
 
-        prev_line = line;
+        prev_line = line.clone();
+
+        pm3 = pm2;
+        pm2 = pm1;
+        pm1 = Some(line);
     }
 
     tidy_error!(bad, "{file}: reached end of file expecting `{END_MARKER}`")