A three-way merge is a merge between a base version of a file and two diverged versions. Three-way merges are the corner-stone of automatic merges in modern version control systems.
More information:
- Wikipedia: Merge (revision control).
Questions tagged [three-way-merge]
30 questions
205
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Why is a 3-way merge advantageous over a 2-way merge?
Wikipedia says a 3-way merge is less error-prone than a 2-way merge, and often times doesn't need user intervention. Why is this the case?
An example where a 3-way merge succeeds and a 2-way merge fails would be helpful.
Johannes Bittner
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Subversion: How to merge only specific revisions into trunk when multiple consecutive changes are made in a branch?
I have been using TortoiseSVN, svn, and subclipse and I think I understand the basics, but there's one thing that's been bugging me for a while: Merging introduces unwanted code. Here's the steps.
trunk/test.txt@r2. A test file was created with 'A'…
Eugene Yokota
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2 answers
Why are Mercurial backouts in one branch affecting other branches?
This is a difficult situation to explain, so bear with me. I have a Mercurial repository with 2 main branches, default and dev.
Work is usually done in a named branch off of dev (a feature branch). There may be many feature branches at any one time.…
James Allardice
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Controlling manual alignment in 'Beyond Compare's 3-way merge
When doing a 3-way merge in 'Beyond Compare', we can get the following misalignment due to code similarity (The X's are the deleted code segments, and only two files are shown):
/* XXXXXXXXXXXXXXXXX
somefunc() …
Basel Shishani
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10
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5 answers
How can I use Beyond Compare 3 as the diff3-cmd for svn?
I saw this posting which explained how to get BC3 working as the diff tool for Subversion... but what about using Beyond Compare 3 to do 3-way merge/compares?
paxos1977
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2 answers
non-graphical 3-way merge tool
I currently use RCS' merge command to do 3-way merges, but one thing has always annoyed me about it. If I use the -A option, the same change made in both files shows up as a conflict:
<<<<<<< file1
file1 line 1
||||||| orig
orig line 1
=======
file2…
David
7
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3 answers
3-way merge in JavaScript or PHP
Does anyone know of an Open Source three-way merge implementation in JavaScript or PHP? I want to merge plain text files without the need to rely on any server side binaries.
I found a few solutions for creating diffs, but no merge implementations.
Andreas Gohr
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6
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3 answers
How do I specify a merge-base to use in a 'hg merge'
I'm trying to do a complicated merge in a complicated hg repository. I'm not happy with the "newest shared ancestor" that Mercurial chooses to use as the "base" to perform the merge.
I'd like to specify a specific commit of my own choice to use as…
Lucas Meijer
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5
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5 answers
Tool for 3-Way Binary (Hex) File Comparison?
I have a set of binary configuration files with three versions each -- an original, and two differently-modified versions of each file. I need to be able to see the differences between the two versions as well as the original, all at the same…
Brian Lacy
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4 answers
Three-way-merge - different philosophies?
I've been a user of UltraCompare Pro since it first came out, and I think it's a very full-featured compare and merge tool. However, since I have been looking more closely into DVCS, I found that it handles three-way merges differently than (most?)…
Tim Pietzcker
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5 answers
Best practice tools and techniques for merging a derived code snapshot with updated upstream code?
The situation is as follows: it is necessary to merge in changes from an upstream code base (from V1, to V2), into a third code base S1 that is derived/branched from V1, to produce a new code base S2.
We have access to version control for logs and…
grrussel
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3
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Why does a merge need you to consider the common ancestor?
I'm learning Git, and am finding the tutorial on this site very useful. On that page, concerning merging, it includes:
+---------- (D) ---------------+
/ | \
(A) -- (B) -- (C) -------------- (E) --…
user146043
3
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2 answers
Three way dictionary deep merge in python
I would like to merge two dictionaries A and B, knowing a common previous state C of both dictionaries. I need the merge to occur in subdictionaries too. In the case of real conflict, I need an exception to be raised.
1 - In the following example,…
azmeuk
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Resolving Merge Conflict in IDE Whilst Retaining 3-Way Merge Info
(I am using SourceTree as my Git tool, Beyond Compare to resolve merge conflicts, and Eclipse as my Java IDE.)
The conflict is complex enough that I cannot solve it in the merge tool, and will have to resolve it manually (across multiple…
Mark Chimes
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Implementing a three-way diff/merge
I'm trying to implement a three-way diff/merge algorithm (in python) between, say, the base version X and two different derivative versions A and B, and I'm having trouble figuring out how to handle some changes.
I have a line-by-line diff from X to…
brianmearns
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