use signalling to timeout mwparserfromhell instead of asyncio.

src/wikiq/wikitext_parser.py

@@ -1,7 +1,8 @@
 """Shared wikitext parser with caching to avoid duplicate parsing."""
 from __future__ import annotations
 
-import asyncio
+import signal
+
 import mwparserfromhell
 
 PARSER_TIMEOUT = 60  # seconds
@@ -22,22 +23,28 @@ class WikitextParser:
         self._cached_wikicode = None
         self.last_parse_timed_out: bool = False
 
-    async def _parse_async(self, text: str):
-        """Parse wikitext with timeout protection."""
-        try:
-            result = await asyncio.wait_for(
-                asyncio.to_thread(mwparserfromhell.parse, text),
-                timeout=PARSER_TIMEOUT
-            )
-            return result, False
-        except TimeoutError:
-            return None, True
+    def _timeout_handler(self, signum, frame):
+        raise TimeoutError("mwparserfromhell parse exceeded timeout")
 
     def _get_wikicode(self, text: str):
         """Parse text and cache result. Returns cached result if text unchanged."""
-        if text != self._cached_text:
+        if text == self._cached_text:
+            return self._cached_wikicode
+
+        old_handler = signal.signal(signal.SIGALRM, self._timeout_handler)
+        signal.alarm(PARSER_TIMEOUT)
+        try:
+            self._cached_wikicode = mwparserfromhell.parse(text)
             self._cached_text = text
-            self._cached_wikicode, self.last_parse_timed_out = asyncio.run(self._parse_async(text))
+            self.last_parse_timed_out = False
+        except TimeoutError:
+            self._cached_wikicode = None
+            self._cached_text = text
+            self.last_parse_timed_out = True
+        finally:
+            signal.alarm(0)
+            signal.signal(signal.SIGALRM, old_handler)
+
         return self._cached_wikicode
 
     def extract_external_links(self, text: str | None) -> list[str] | None: