Revert "Get rollback inconsistencies using multiple processes (#3778)" (

#3803)

This reverts commit 3ddaf41.

bugbug/bug_snapshot.py

@@ -4,7 +4,6 @@
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from logging import INFO, basicConfig, getLogger
-from multiprocessing.pool import Pool
 
 import dateutil.parser
 from dateutil.relativedelta import relativedelta
@@ -869,21 +868,17 @@ def parse_flag_change(change):
     return bug
 
 
-def _try_rollback(bug):
-    try:
-        return rollback(bug, do_assert=True), True
-    except Exception:
-        logger.exception("Failed to rollback bug %s", bug["id"])
-        return bug, False
+def get_inconsistencies(bugs):
+    inconsistencies = []
 
+    for bug in bugs:
+        try:
+            rollback(bug, do_assert=True)
+        except Exception:
+            logger.exception("Failed to rollback bug %s", bug["id"])
+            inconsistencies.append(bug)
 
-def get_inconsistencies(bugs):
-    with Pool() as p:
-        return [
-            bug
-            for bug, is_successful in p.imap(_try_rollback, bugs, chunksize=1024)
-            if not is_successful
-        ]
+    return inconsistencies
 
 
 if __name__ == "__main__":