fix interruption handling by breaking the diff loop.

src/wikiq/__init__.py

@@ -875,6 +875,8 @@ class WikiqParser:
                     new_diffs = []
                     diff_timeouts = []
                     for i, text in enumerate(row_buffer["text"]):
+                        if self.shutdown_requested:
+                            break
                         diff, timed_out = diff_with_timeout(differ, last_text, text)
                         if timed_out:
                             print(f"WARNING! wikidiff2 timeout for rev: {row_buffer['revid'][i]}. Falling back to default limits.", file=sys.stderr)
@@ -882,6 +884,9 @@ class WikiqParser:
                         new_diffs.append(diff)
                         diff_timeouts.append(timed_out)
                         last_text = text
+                    if self.shutdown_requested:
+                        print("Shutdown requested, closing writers...", file=sys.stderr)
+                        break
                     row_buffer["diff"] = [
                         [
                             entry