Memories of Bug-Fixes Sunghun Kim, Kai Pan, Jim Whitehead {hunkim, pankai, ejw}@cs.ucsc.edu University of California, Santa Cruz

Horizontal and Vertical Bug Patterns Buffer over run Horizontal : general bugs Vertical : project specific Null dereference JEdit example Eclipse example

Bug-Fix Memories – Basic Idea Extract patterns in bug fix change history …… Bug fix changes in revision 1 .. n-1 Memory

Bug-Fix Memories – Basic Idea Extract patterns in bug fix change history …… Search for patterns against Memory Bug fix changes in revision 1 .. n-1 Memory Code to examine

Bug-introducing and Bug-fix Changes Development history of foo.java SCM log message: “Bug #567 fixed” “ bug fix” Bug #567 entered into issue tracking system (bug finally observed and recorded) Software change that introduces the bug “bug-introducing”

Kenyon Processing SCM Repository Filesystem Extract Automated configuration extraction Save Persist gathered metrics & facts Kenyon Repository (RDBMS/ Hibernate) Analyze Query DB, add new facts Analysis Software (e.g., IVA) Compute Fact extraction (metrics, static analysis) Kenyon

Commits, Transactions & Configurations transactions configurations CVS file commits Added feature X Fixed null ptr bug Modified button text Added feature Y log message

Hunks, and Hunk Pairs Revision n-1 (has bug hunks) Revision n (has fix hunks) modification addition deletion added hunk hunk pair type deleted hunk empty deleted hunk empty added hunk

IDE Integration Bug detection Fix suggestion

Half and Full Hit Build memories based on transaction 1 .. n-1 …… Transaction 1 .. n-1 Memories Bug | Fix Fix change case at transaction n Half hit Full hit

True and False Positives Build memories based on transaction 1 .. n-1 …… False positive half hit, if found True positive half hit, if found Transaction 1 .. n-1 Memories Non-fix change case at transaction n Fix change case at transaction n

True Positive Hit Rates

False Positive Hit Rates

True Positive and False Positive Full Hit Rates