add test for cycles, but ignored because of #188

src/fmt_md_inlines.rs

@@ -178,8 +178,8 @@ impl<'md> MdInlinesWriter<'md> {
     fn add_footnote(&mut self, label: &'md String, text: &'md Vec<MdElem>) {
         if self.seen_footnotes.insert(label) {
             self.pending_references.footnotes.insert(label, text);
+            self.find_references_in_footnote_elems(text);
         }
-        self.find_references_in_footnote_elems(text);
     }
 
     /// Searches the footnote's text to find any link references and additional footnotes.

tests/md_cases/footnotes_in_footnotes.toml

@@ -86,3 +86,19 @@ output = '''
   }
 }
 '''
+
+
+[expect."cyclic reference does't cause infinite loop"]
+ignored = true # #188
+# When ready to add this back in, add the following to the input markdown:
+#
+#     - DDD: footnote contains cycle[^cycle]
+#
+#     [^cycle]: this footnote references itself[^cycle]
+#
+cli_args = ['- DDD | P: *']
+output = '''
+- DDD: footnote contains cycle[^cycle]
+
+[^cycle]: this footnote references itself[^cycle]
+'''