buildbot/buildbot — pull request #1289 by delanne (2014-10-24 14:17:44+00:00)
Title: Fix bug in master/buildbot/db/sourcestamps.py

Dustin says:

```
you only get multiple changes attached to a sourcestamp if you have a long enough treeStableTimer that the schedule deals with both changes at the same time
asking "which changes led to this sourcestamp", translated to, say, git terms means "which commits led to this revision"
to which the only logical answer is "all of them"
what we really want is "what are the commits *between* this sourcestamp and that sourcestsamp"
so a sourcestamp will have a single change (the commit that generated it)
and we'll do some tree traversal to answer theq uesetion
but until that happens, it's this kind of crappy "it depends what the scheduler sees" answer :(
```

But with the current implementation, a sourcestamp is created for each change, because "revision" (GIT SHA1 in case of the gitpoller) is used to calculate the ss_hash.
As a consequence, buildbot creates a new sourcestamp for each new changes.