Fix an edge case when we recurse too deeply.

mwparserfromhell/parser/tokenizer.c

@@ -2272,7 +2272,8 @@ static PyObject* Tokenizer_parse_style(Tokenizer* self)
                     return NULL;
                 return Tokenizer_pop(self);
             }
-            self->topstack->context |= LC_STYLE_PASS_AGAIN;
+            if (context & LC_STYLE_ITALICS)
+                self->topstack->context |= LC_STYLE_PASS_AGAIN;
         }
         for (i = 0; i < ticks; i++) {
             if (Tokenizer_emit_char(self, *"'"))

mwparserfromhell/parser/tokenizer.py

@@ -823,7 +823,8 @@ class Tokenizer(object):
         except BadRoute as route:
             self._head = reset
             if route.context & contexts.STYLE_PASS_AGAIN:
-                stack = self._parse(route.context | contexts.STYLE_SECOND_PASS)
+                new_ctx = contexts.STYLE_ITALICS | contexts.STYLE_SECOND_PASS
+                stack = self._parse(new_ctx)
             else:
                 return self._emit_text("''")
         self._emit_style_tag("i", "''", stack)
@@ -912,7 +913,8 @@ class Tokenizer(object):
                 if self._context & contexts.STYLE_SECOND_PASS:
                     self._emit_text("'")
                     return self._pop()
-                self._context |= contexts.STYLE_PASS_AGAIN
+                if self._context & contexts.STYLE_ITALICS:
+                    self._context |= contexts.STYLE_PASS_AGAIN
             self._emit_text("'" * ticks)
         elif ticks == 2:
             self._parse_italics()