Sync central issue details downwards when creating brand new local is…

…sues

Summary:
When a new local issue is added and it corresponds to an existing central issue, we want to sync down those triage details so the local issue matches.

This diff does not change anything about how SAPP handles existing local issues: if an issue already exists, it is not modified and all downwards syncing happens from WWW.

If this diff causes issues, it can be disabled using https://www.internalfb.com/intern/justknobs/?name=sapp%2Fsapp#sync_local_issues_to_existing_central_issues

See [Central Issues Cutover Plan](https://docs.google.com/document/d/1Bx1zeiGDc_ygrp7tPNo21X3QTUFjNplhj7VmA5etGjc)

Reviewed By: yuhshin-oss

Differential Revision: D61165240

fbshipit-source-id: fff505312e78ceab9ecc41f7570c0477dea68b09

sapp/pipeline/database_saver.py

@@ -129,13 +129,12 @@ def _save(self) -> RunSummary:
                 run_id = self.summary["run"].id.resolved()
                 log.info("Created run: %d", run_id)
 
-            # Get full list of issues before bulk_saver prunes them during _prepare
-            issues = self.bulk_saver.get_items_to_add(Issue)
+            self._save_central_issues_and_sync_local_issues(
+                self.summary["run"], self.bulk_saver.get_items_to_add(Issue)
+            )
 
             self.bulk_saver.save_all(self.database)
 
-            self._save_central_issues(self.summary["run"], issues)
-
             # Now that the run is finished, fetch it from the DB again and set its
             # status to FINISHED.
             with self.database.make_session() as session:
@@ -172,7 +171,10 @@ def _get_dry_run_summary(self) -> RunSummary:
             ),
         )
 
-    def _save_central_issues(self, run: TRun, issues: List[Issue]) -> None:
-        """Subclasses may implement this to save issue data to a second location before
-        the run status is changed to FINISHED"""
+    def _save_central_issues_and_sync_local_issues(
+        self, run: TRun, local_issues: List[Issue]
+    ) -> None:
+        """Subclasses may implement this to save issue data to a second location before the issues
+        saved and the run status is changed to FINISHED. They can also modify details
+        of yet-to-be-created local issues to match existing central issues."""
         pass