JDiff

Introduction

JDiff is a tool used to diff a java bug file and a repair version for the bug.

It will output code snippets representing bug snippet and repair snippet, and common context that is shared between codes, in the form of edges & nodes, after comparing code files.

All is done by differing asts.

Usage

java -jar jdiff.jar [diff_strategy] [path1] [path2] ([ctx])

• diff_strategy: strategy used to diff tree ( support three currently )
• path1: java bug code ( string )
• path2: java repair code ( string )
• ctx: need context or not ( true or false )

Tree Diff Strategy

COMMON_PARENT

split bug snippet and repair snippet by localizing node which is the common root of different sub asts corresponding to bug part and repair part.

• diff_strategy = 0

COMMON_PARENT_SIDE

on basis of COMMON_PARENT, also remove context from both side until meet unmatched nodes, non recursive.

• diff_strategy = 1

COMMON_PARENT_ALL_NONRECURSIVE

on basis of COMMON_PARENT_SIDE, also remove context from inside left, non recursive.

• diff_strategy = 2

COMMON_PARENT_ALL_RECURSIVE

on basis of COMMON_PARENT_SIDE, also remove context from inside, recursive, not implemented yet.

• diff_strategy = 3

Demo

bug code

public class test {
  public void f() {
    int t=1;
    int a=1;
    int b=1;
    int c=1;
    int d=1;
    int p=1;
  }
}

repair code

public class test {
  public void f() {
    int t=1;
    int x=1;
    int a=1;
    int b=1;
    int c=1;
    int d=1;
    int y=1;
    int p=1;
  }
}

COMMON_PARENT

bug snippet

{
    int t = 1;
    int a = 1;
    int b = 1;
    int c = 1;
    int d = 1;
    int p = 1;
}

repair snippet

{
    int t = 1;
    int x = 1;
    int a = 1;
    int b = 1;
    int c = 1;
    int d = 1;
    int y = 1;
    int p = 1;
}

COMMON_PARENT_SIDE

bug snippet

{
    int a = 1;
    int b = 1;
    int c = 1;
    int d = 1;
}

repair snippet

{
    int x = 1;
    int a = 1;
    int b = 1;
    int c = 1;
    int d = 1;
    int y = 1;
}

COMMON_PARENT_ALL_NONRECURSIVE

bug snippet

{
}

repair snippet

{
    int x = 1;
    int y = 1;
}