I have a whole bunch of pairs of files that have subtle differences. We use subversion for a source control, and I like the Merge/Diff utility that comes with TortoiseSVN for windows. And I can use this utility to manually compare/merge two files together. My question is this: How can I programmatically merge two files together the same way this utility does (and ignore and flag files that have conflicts)?
A:
A few options I know about:
- Sharp SVN as used by the ANKH source control provider for Visual Studio. It's slow to grab repositories however
- DotSVN - '.Net port of Subversion'
- If veering away from subversion isn't a problem, you could try Google's Diff Match Patch.
I'm not sure if the two subversion projects implement merging, but I imagine it's a server command. The diff won't be and I'd recommend the Google one for that.
I may be way off the mark if you just want to automate tortoise.
Chris S
2010-01-11 19:20:33
+2
A:
I would suggest using one of the .NET libraries that support an established merge algorithm, such as suggested in this question: http://stackoverflow.com/questions/138331/any-decent-text-diff-merge-engine-for-net
No idea about quality, I also stumbled across this: http://razor.occams.info/code/diff/
Godeke
2010-01-11 19:23:43
No success with anything mentioned on that question, and the link you included has a blatant message on it indicating that the code is buggy.
Josh Stodola
2010-01-26 04:20:48
If you know your data sets, it may be simpler to hand tune something yourself. (In another comment you say that they are "mostly inserts", for example). I did run across a guy who build a diff utility and encapsulated the diff itself in a library: http://www.menees.com/index.html
Godeke
2010-01-27 23:47:50
A:
Merging two files where there is no conflict, without human intervention, is probably not a good idea, unless you can easily tell what the change actually is, such as having the before-version of both files (like Subversion does.)
For instance, given the following two files, what is the correct course of action? (The # column is the line number, gaps means lines are missing)
--- File #1 ------------------------ --- File #2 ------------------------
1 This is the first line 1 This is the first line
2 This is the second line 2 This is the second line
3 This is the third line
4 This is the fourth line 3 This is the fourth line
4 This is the fifth line
5 This is the sixth line 5 This is the sixth line
So, what is the correct result here?
Lasse V. Karlsen
2010-01-11 19:26:40
Sorry, I should have mentioned that I do have "before versions" just like Subversions, that's why I figured I could tap into the algorithm because it is a perfect fit.
Josh Stodola
2010-01-11 19:55:19
In the example you provided, there would be a conflict on lines 3, 4, and 5, correct? So this file would not get merged, but flagged for human intervention.
Josh Stodola
2010-01-26 18:16:34
Also, I want to mention that 95% of the time, the modifications are going to be inserted lines, so conflicts should be rare.
Josh Stodola
2010-01-26 18:18:55