How to interactively (visually) resolve conflicts in SourceTree / git

Question

I'm using (Windows) SourceTree for my git project. I can do it in either command prompt or Linux terminal.

But, I'm wondering whether there is a nice way to interactively and visually resolve conflicts. For example, if pull detects conflicts, popping up a GUI-based conflict tool (e.g., P4Merge). Is it possible?

I am always doing manual conflict resolving, which is just painful.

This is, for example, a git pull message, from SourceTree.

git -c diff.mnemonicprefix=false -c core.quotepath=false pull --no-commit origin master
From W:\repo\
 * branch            master     -> FETCH_HEAD   

Updating 33c07bf..41e0249

error: Your local changes to the following files would be overwritten by merge:
    foo.cpp
    goo.cpp
    goo.hpp
Please, commit your changes or stash them before you can merge.
Aborting    

Completed with errors, see above.

Answer 1

From SourceTree, click on Tools->Options. Then on the "General" tab, make sure to check the box to allow SourceTree to modify your Git config files.

Then switch to the "Diff" tab. On the lower half, use the drop down to select the external program you want to use to do the diffs and merging. I've installed KDiff3 and like it well enough. When you're done, click OK.

Now when there is a merge, you can go under Actions->Resolve Conflicts->Launch External Merge Tool.