fix: insert AllowBlanklineBefore atom

topiary-core/src/atom_collection.rs

@@ -218,7 +218,11 @@ impl AtomCollection {
         match name {
             "allow_blank_line_before" => {
                 if self.blank_lines_before.contains(&node.id()) {
+                    // If there already was a blankline, keep it
                     self.prepend(Atom::Blankline, node, predicates);
+                } else {
+                    // Otherwise, allow the query processing to insert blank lines that we won't remove
+                    self.append(Atom::AllowBlanklineBefore, node, predicates);
                 }
             }
             "append_delimiter" => self.append(

topiary-core/src/lib.rs

@@ -46,6 +46,10 @@ pub enum Atom {
     /// We don't allow consecutive `Hardline`, but a `Blankline` will render two
     /// newlines to produce a blank line.
     Blankline,
+    /// Sometimes, Topiary needs to be instructed that a blank line is allowed before the current node.
+    /// Previously, this was done in the collection phase, however, we also don't want to remove lines that were added by queries.
+    /// As such, this node informs the post-processing step not to remove any double Hardlines or single Blanklines.
+    AllowBlanklineBefore,
     /// A "no-op" atom that will not produce any output.
     #[default]
     Empty,