Fix table reordering unstable for empty sub-tables

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pyproject-fmt-rust"
-version = "1.1.0"
+version = "1.1.1"
 description = "Format pyproject.toml files"
 repository = "https://github.com/tox-dev/pyproject-fmt"
 readme = "README.md"

rust/src/helpers/table.rs

@@ -72,8 +72,7 @@ impl Tables {
     pub fn reorder(&mut self, root_ast: &SyntaxNode, order: &[&str]) {
         let mut to_insert = Vec::<SyntaxElement>::new();
         let mut entry_count: usize = 0;
-
-        let order = calculate_order(&self.header_to_pos, order);
+        let order = calculate_order(&self.header_to_pos, &self.table_set, order);
         let mut next = order.clone();
         if !next.is_empty() {
             next.remove(0);
@@ -104,7 +103,11 @@ impl Tables {
     }
 }
 
-fn calculate_order(header_to_pos: &HashMap<String, Vec<usize>>, ordering: &[&str]) -> Vec<String> {
+fn calculate_order(
+    header_to_pos: &HashMap<String, Vec<usize>>,
+    table_set: &[RefCell<Vec<SyntaxElement>>],
+    ordering: &[&str],
+) -> Vec<String> {
     let max_ordering = ordering.len() * 2;
     let key_to_pos = ordering
         .iter()
@@ -115,6 +118,7 @@ fn calculate_order(header_to_pos: &HashMap<String, Vec<usize>>, ordering: &[&str
     let mut header_pos: Vec<(String, usize)> = header_to_pos
         .clone()
         .into_iter()
+        .filter(|(_k, v)| v.iter().any(|p| !table_set.get(*p).unwrap().borrow().is_empty()))
         .map(|(k, v)| (k, *v.iter().min().unwrap()))
         .collect();
 

rust/src/main.rs

@@ -178,7 +178,7 @@ mod tests {
         (3, 8)
     )]
     #[case::subsubtable(
-        indoc ! {r#"
+        indoc ! {r"
     [project]
     [tool.coverage.report]
     a = 2
@@ -188,7 +188,7 @@ mod tests {
     a = 1
     [tool.coverage.run]
     a = 3
-    "#},
+    "},
         indoc ! {r#"
     [project]
     classifiers = [
@@ -239,6 +239,36 @@ mod tests {
         true,
         (3, 8)
     )]
+    #[case::unstable_issue_18(
+        indoc ! {r#"
+    [project]
+    requires-python = "==3.12"
+    classifiers = [
+        "Programming Language :: Python :: 3 :: Only",
+        "Programming Language :: Python :: 3.12",
+    ]
+    [project.urls]
+    Source = "https://github.com/VWS-Python/vws-python-mock"
+
+    [tool.setuptools]
+    zip-safe = false
+    "#},
+        indoc ! {r#"
+    [project]
+    requires-python = "==3.12"
+    classifiers = [
+      "Programming Language :: Python :: 3 :: Only",
+      "Programming Language :: Python :: 3.12",
+    ]
+    urls.Source = "https://github.com/VWS-Python/vws-python-mock"
+
+    [tool.setuptools]
+    zip-safe = false
+    "#},
+        2,
+        true,
+        (3, 8)
+    )]
     fn test_format_toml(
         #[case] start: &str,
         #[case] expected: &str,
@@ -256,6 +286,6 @@ mod tests {
         let got = format_toml(start, &settings);
         assert_eq!(got, expected);
         let second = format_toml(got.as_str(), &settings);
-        assert_eq!(got, second);
+        assert_eq!(second, got);
     }
 }