From 071c79f6fbb757ada49b92dd91c36412076229e7 Mon Sep 17 00:00:00 2001
From: Robert Collins <rbtcollins@hp.com>
Date: Fri, 4 Jul 2014 19:13:27 +1200
Subject: [PATCH] Create local refs to prevent pruning

By default git will prune dangling commits more than 2 weeks old. All
the unmerged versions of reviews pushed up more than 2 weeks ago count
as such commits, so we're downloading all the history again and again
each time git-gc --auto ends up being invoked (which is triggered
amongst other things by loose object counts. This leads to random
stalls in gertty when it has to redownload those objects - and this
is obviously worse when offline.

This commit adds refs to prevent this behaviour, but doesn't remove
them at any point. We probably want to facilitate gc of
merged/abandoned/ignored commits at some point. I'm not sure if that
needs to happen in this commit or if it could be added later.

Change-Id: I01c61fd65207fe0dc99208241eefd5d6432c2ad0
---
 gertty/sync.py        |  4 ++--
 gertty/view/change.py | 13 ++++++++-----
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/gertty/sync.py b/gertty/sync.py
index 0352d46..a75b319 100644
--- a/gertty/sync.py
+++ b/gertty/sync.py
@@ -255,7 +255,7 @@ class SyncChangeTask(Task):
                                            sync.app.config.password, url[1])
                     url = urlparse.urlunsplit(url)
                 if (not revision) or self.force_fetch:
-                    fetches[url].append(ref)
+                    fetches[url].append('+%(ref)s:%(ref)s' % dict(ref=ref))
                 if not revision:
                     revision = change.createRevision(remote_revision['_number'],
                                                      remote_revision['commit']['message'], remote_commit,
@@ -435,7 +435,7 @@ class FetchRefTask(Task):
             url = urlparse.urlunsplit(url)
         self.log.debug("git fetch %s %s" % (url, self.refs))
         repo = sync.app.getRepo(self.project_name)
-        refs = self.refs
+        refs = ['+%(ref)s:%(ref)s' % dict(ref=ref) for ref in self.refs]
         try:
             repo.fetch(url, refs)
         except Exception:
diff --git a/gertty/view/change.py b/gertty/view/change.py
index 66b9e96..443563a 100644
--- a/gertty/view/change.py
+++ b/gertty/view/change.py
@@ -359,7 +359,7 @@ This Screen
         self.refresh()
 
     def checkGitRepo(self):
-        missing_revisions = False
+        missing_revisions = set()
         change_number = None
         change_id = None
         with self.app.db.getSession() as session:
@@ -368,12 +368,15 @@ This Screen
             change_id = change.id
             repo = self.app.getRepo(change.project.name)
             for revision in change.revisions:
-                if not (repo.hasCommit(revision.parent) and
-                        repo.hasCommit(revision.commit)):
-                    missing_revisions = True
+                if not repo.hasCommit(revision.parent):
+                    missing_revisions.add(revision.parent)
+                if not repo.hasCommit(revision.commit):
+                    missing_revisions.add(revision.commit)
+                if missing_revisions:
                     break
         if missing_revisions:
-            self.app.log.warning("Missing some commits for change %s" % change_number)
+            self.app.log.warning("Missing some commits for change %s %s",
+                change_number, missing_revisions)
             task = sync.SyncChangeTask(change_id, force_fetch=True,
                                        priority=sync.HIGH_PRIORITY)
             self.app.sync.submitTask(task)