  Finding and fixing buggy code is an important and cost-intensive maintenance
task, and static analysis (SA) is one of the methods developers use to perform
it. SA tools warn developers about potential bugs by scanning their source code
for commonly occurring bug patterns, thus giving those developers opportunities
to fix the warnings (potential bugs) before they release the software.
Typically, SA tools scan for general bug patterns that are common to any
software project (such as null pointer dereference), and not for project
specific patterns. However, past research has pointed to this lack of
customizability as a severe limiting issue in SA. Accordingly, in this paper,
we propose an approach called Ammonia, which is based on statically analyzing
changes across the development history of a project, as a means to identify
project-specific bug patterns. Furthermore, the bug patterns identified by our
tool do not relate to just one developer or one specific commit, they reflect
the project as a whole and compliment the warnings from other SA tools that
identify general bug patterns. Herein, we report on the application of our
implemented tool and approach to four Java projects: Ant, Camel, POI, and
Wicket. The results obtained show that our tool could detect 19 project
specific bug patterns across those four projects. Next, through manual
analysis, we determined that six of those change patterns were actual bugs and
submitted pull requests based on those bug patterns. As a result, five of the
pull requests were merged.
