Bug 538554

Summary:	Compare should detect and show moved blocks of lines
Product:	[Eclipse Project] Platform	Reporter:	David Balažic <david.balazic>
Component:	Compare	Assignee:	Platform-Compare-Inbox <platform-compare-inbox>
Status:	NEW ---	QA Contact:
Severity:	enhancement
Priority:	P3	CC:	gautier.desaintmartinlacaze
Version:	4.6
Target Milestone:	---
Hardware:	PC
OS:	All
Whiteboard:

Description David Balažic

2018-09-03 10:08:01 EDT

When a block of lines is moved, it should be detected and displayed.

Example:

 - one document
1
2
3
4
5
6

 - other document
4
5
1
2
3
6

Comparing them currently shows:
 - 
 - 3 lines before the last line were added

By this proposal, it should display this information:
 - 3 lines at beginning were moved to before the last number

This way the user knows, that the two blocks are actually the same.

For example in a Java source code, a moved method would be displayed as "method moved (ergo: no real change)" instead of current "a method was removed" and "a method was added".

There is some discussion about algorithms and existing product that do this here:
 - https://stackoverflow.com/questions/10066129/is-there-a-diff-like-algorithm-that-handles-moving-block-of-lines
 - http://www.donationcoder.com/forum/index.php?topic=35448.0

Comment 1 David Balažic

2018-09-03 10:09:03 EDT

Sorry, a typo:

It should say:

Comparing them currently shows:
 - 3 lines from the beginning were deleted
 - 3 lines before the last line were added