Add renumber restart test

src/lists.rs

@@ -26,21 +26,61 @@ fn drop_deeper(indent: usize, counters: &mut Vec<(usize, usize)>) {
     }
 }
 
+fn is_plain_paragraph_line(line: &str) -> bool {
+    line.trim_start()
+        .chars()
+        .next()
+        .is_some_and(char::is_alphanumeric)
+}
+
+/// Remove counters deeper than or equal to `indent`.
+///
+/// ```
+/// use mdtablefix::lists::pop_counters_upto;
+/// let mut counters = vec![(0usize, 1usize), (4, 2), (8, 3)];
+/// pop_counters_upto(&mut counters, 4);
+/// assert_eq!(counters, vec![(0, 1)]);
+/// ```
+pub fn pop_counters_upto(counters: &mut Vec<(usize, usize)>, indent: usize) {
+    while counters.last().is_some_and(|(d, _)| *d >= indent) {
+        counters.pop();
+    }
+}
+
+fn handle_paragraph_restart(line: &str, prev_blank: bool, counters: &mut Vec<(usize, usize)>) {
+    let indent_end = line
+        .char_indices()
+        .find(|&(_, c)| !c.is_whitespace())
+        .map_or_else(|| line.len(), |(i, _)| i);
+    let indent = indent_len(&line[..indent_end]);
+
+    if prev_blank
+        && counters
+            .last()
+            .is_some_and(|(d, _)| indent <= *d && is_plain_paragraph_line(line))
+    {
+        pop_counters_upto(counters, indent);
+    }
+}
+
 #[must_use]
 pub fn renumber_lists(lines: &[String]) -> Vec<String> {
     let mut out = Vec::with_capacity(lines.len());
     let mut counters: Vec<(usize, usize)> = Vec::new();
     let mut in_code = false;
+    let mut prev_blank = lines.first().is_none_or(|l| l.trim().is_empty());
 
     for line in lines {
         if is_fence(line) {
             in_code = !in_code;
             out.push(line.clone());
+            prev_blank = false;
             continue;
         }
 
         if in_code {
             out.push(line.clone());
+            prev_blank = line.trim().is_empty();
             continue;
         }
 
@@ -58,6 +98,7 @@ pub fn renumber_lists(lines: &[String]) -> Vec<String> {
                 }
             };
             out.push(format!("{indent_str}{current}.{sep}{rest}"));
+            prev_blank = false;
             continue;
         }
 
@@ -67,8 +108,10 @@ pub fn renumber_lists(lines: &[String]) -> Vec<String> {
             .map_or_else(|| line.len(), |(i, _)| i);
         let indent_str = &line[..indent_end];
         let indent = indent_len(indent_str);
+        handle_paragraph_restart(line, prev_blank, &mut counters);
         drop_deeper(indent, &mut counters);
         out.push(line.clone());
+        prev_blank = line.trim().is_empty();
     }
 
     out

tests/data/renumber_paragraph_restart_expected.txt

@@ -0,0 +1,26 @@
+1. First item
+
+2. Second item
+
+   Here’s a plain paragraph within the second item
+
+3. Third item
+
+Here's a plain paragraph at a lower indent level
+
+1. Fourth item
+
+| A   | B   |
+| --- | --- |
+| 1   | 2   |
+
+2. Fifth item
+
+3. Sixth item
+
+```js
+// fenced code block at lower indent
+console.log('hello');
+```
+
+4. Seventh item

tests/data/renumber_paragraph_restart_input.txt

@@ -0,0 +1,26 @@
+1. First item
+
+2. Second item
+
+   Here’s a plain paragraph within the second item
+
+3. Third item
+
+Here's a plain paragraph at a lower indent level
+
+4. Fourth item
+
+| A   | B   |
+| --- | --- |
+| 1   | 2   |
+
+5. Fifth item
+
+6. Sixth item
+
+```js
+// fenced code block at lower indent
+console.log('hello');
+```
+
+7. Seventh item

tests/integration.rs

@@ -1010,6 +1010,19 @@ fn test_renumber_table_in_list() {
     assert_eq!(renumber_lists(&input), expected);
 }
 
+#[test]
+fn test_renumber_restart_after_paragraph() {
+    let input: Vec<String> = include_str!("data/renumber_paragraph_restart_input.txt")
+        .lines()
+        .map(str::to_string)
+        .collect();
+    let expected: Vec<String> = include_str!("data/renumber_paragraph_restart_expected.txt")
+        .lines()
+        .map(str::to_string)
+        .collect();
+    assert_eq!(renumber_lists(&input), expected);
+}
+
 #[test]
 fn test_format_breaks_basic() {
     let input = vec!["foo", "***", "bar"]

tests/lists.rs

@@ -0,0 +1,56 @@
+use mdtablefix::{lists::pop_counters_upto, renumber_lists};
+
+macro_rules! lines_vec {
+    ($($line:expr),* $(,)?) => {
+        vec![$($line.to_string()),*]
+    };
+}
+
+#[test]
+fn pop_counters_removes_deeper_levels() {
+    let mut counters = vec![(0usize, 1usize), (4, 2), (8, 3)];
+    pop_counters_upto(&mut counters, 4);
+    assert_eq!(counters, vec![(0, 1)]);
+}
+
+#[test]
+fn pop_counters_no_change_when_indent_deeper() {
+    let mut counters = vec![(0usize, 1usize), (4, 2)];
+    pop_counters_upto(&mut counters, 6);
+    assert_eq!(counters, vec![(0, 1), (4, 2)]);
+}
+
+#[test]
+fn restart_after_lower_paragraph() {
+    let input = lines_vec!("1. One", "", "Paragraph", "3. Next");
+    let expected = lines_vec!("1. One", "", "Paragraph", "1. Next");
+    assert_eq!(renumber_lists(&input), expected);
+}
+
+#[test]
+fn no_restart_without_blank() {
+    let input = lines_vec!("1. One", "Paragraph", "3. Next");
+    let expected = lines_vec!("1. One", "Paragraph", "2. Next");
+    assert_eq!(renumber_lists(&input), expected);
+}
+
+#[test]
+fn no_restart_for_indented_paragraph() {
+    let input = lines_vec!("1. One", "", "  Indented", "3. Next");
+    let expected = lines_vec!("1. One", "", "  Indented", "2. Next");
+    assert_eq!(renumber_lists(&input), expected);
+}
+
+#[test]
+fn no_restart_for_non_plain_line() {
+    let input = lines_vec!("1. One", "", "# Heading", "3. Next");
+    let expected = lines_vec!("1. One", "", "# Heading", "2. Next");
+    assert_eq!(renumber_lists(&input), expected);
+}
+
+#[test]
+fn restart_after_nested_paragraph() {
+    let input = lines_vec!("1. One", "    1. Sub", "", "Paragraph", "3. Next");
+    let expected = lines_vec!("1. One", "    1. Sub", "", "Paragraph", "1. Next");
+    assert_eq!(renumber_lists(&input), expected);
+}