{"id":18138,"date":"2025-06-30T13:25:14","date_gmt":"2025-06-30T17:25:14","guid":{"rendered":"https:\/\/blogs.mathworks.com\/simulink\/?p=18138"},"modified":"2025-06-30T13:25:14","modified_gmt":"2025-06-30T17:25:14","slug":"merging-simulink-models-automatically-in-git","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2025\/06\/30\/merging-simulink-models-automatically-in-git\/","title":{"rendered":"Merging Simulink Models Automatically in Git"},"content":{"rendered":"
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This post is targeted at users developing Simulink models under <\/span>Git<\/span><\/a> source control, but who are not necessarily using the <\/span>MATLAB source control integration<\/span><\/a>.<\/span><\/div>
I personally work in MATLAB and Simulink all day, so the <\/span>MATLAB source control integration<\/span><\/a> usually does the job for me. However, I realize that many Simulink users deal with projects including multiple software and artifacts, and prefer to use Git command-line or a dedicated Git client to manage all that. Examples I see regularly are <\/span>GitHub Desktop<\/span><\/a>, <\/span>GitKraken<\/span><\/a> and <\/span>Sourcetree<\/span><\/a>.<\/span><\/div>
If that's your case, keep reading. This post goes step-by-step through the instructions provided in this documentation page: <\/span>Automatically Merge Models Locally and in CI Pipeline - MATLAB & Simulink<\/span><\/a><\/div>

The Problem<\/span><\/h2>
Let's use a very simple example. I have a folder with a Simulink model<\/span><\/div>
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I initialize the folder for Git, add and commit the model:<\/span><\/div>
git init<\/span><\/span><\/div>
git add simpleMdl.slx<\/span><\/span><\/div>
git commit -a -m \"Initial commit\"<\/span><\/span><\/div><\/div>
I then create a separate branch where I make a modification in Subsystem A and commit the changes.<\/span><\/div>
git checkout -b devA<\/span><\/span><\/div><\/div>
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git commit -a -m \"Added Gain block in A\"<\/span><\/span><\/div><\/div>
At the same time, a second user create another branch and makes modifications to subsystem B<\/span><\/div>
git checkout Master<\/span><\/span><\/div>
git checkout -b devB<\/span><\/span><\/div><\/div>
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git commit -a -m \"Added Bias block in B\"<\/span><\/span><\/div><\/div>
In the meantime, unrelated changes have been committed to the Master branch, so I have a situation like this:<\/span><\/div>
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Now I want to merge branches devA and devB into the master branch<\/span><\/div>
git checkout Master<\/span><\/span><\/div>
git merge devA<\/span><\/span><\/div>
git merge devB<\/span><\/span><\/div><\/div>
At this point, I will get an error that looks like this:<\/span><\/div>
warning: Cannot merge binary files: simpleMdl.slx (HEAD vs. devB)<\/span><\/span><\/div>
Auto-merging simpleMdl.slx<\/span><\/span><\/div>
CONFLICT (content): Merge conflict in simpleMdl.slx<\/span><\/span><\/div>
Automatic merge failed; fix conflicts and then commit the result.<\/span><\/span><\/div><\/div>
As the warning says, since Simulink models are binary files, by default Git cannot merge automatically.<\/span><\/div>
Let's see how to fix that!<\/span><\/div>

Configure the global .gitconfig<\/span><\/h2>
For many releases now, MathWorks ships with Simulink diff and merge tools that can be registered in Git. Those need to be registered in your <\/span>global <\/span>.gitconfig<\/span><\/a> file.<\/span><\/div>
To make it easy, you can simply type this line in MATLAB:<\/span><\/div>
comparisons.ExternalSCMLink.setupGitConfig();<\/span><\/span><\/div>
merge.mlAutoMerge.driver is stored in \"C:\\Users\\grouleau\\.gitconfig\":\r\n \"L:\/MATLAB\/R2025a\/bin\/win64\/mlAutoMerge.bat\" %O %A %B %A.\r\nmergetool.mlMerge.cmd is stored in \"C:\\Users\\grouleau\\.gitconfig\":\r\n \"L:\/MATLAB\/R2025a\/bin\/win64\/mlMerge.bat\" $BASE $LOCAL $REMOTE $MERGED.\r\ndifftool.mlDiff.cmd is stored in \"C:\\Users\\grouleau\\.gitconfig\":\r\n \"L:\/MATLAB\/R2025a\/bin\/win64\/mlDiff.bat\" $LOCAL $REMOTE.<\/div><\/div><\/div><\/div><\/div>
This will automatically add the required lines to your global <\/span>.gitconfig<\/span> file.<\/span><\/div>

Configure your repository<\/span><\/h2>
The next step is to add a <\/span>.gitattributes<\/span><\/a> file to your repository to tell Git that SLX Simulink models are binary files and can be merged using the previously registered tools.<\/span><\/div>
*.slx binary merge=mlAutoMerge<\/span><\/span><\/div>
*.mdl binary merge=mlAutoMerge<\/span><\/span><\/div><\/div>
Note that when using the <\/span>MATLAB source control integration<\/span><\/a>, this <\/span>.gitattributes<\/span> file is automatically generated and added to your repository. If you prefer managing your source control business outside of MATLAB, you need to do it yourself.<\/span><\/div>

Let's Merge!<\/span><\/h2>
With that setup, Git will now be able to automatically merge Simulink models. Here is a screenshot where I use Git Bash to do the merge that had previously failed:<\/span><\/div>
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I can look at the model to confirm that all the changes have been merged properly.<\/span><\/div>
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What if there is a conflict or we cannot auto-merge?<\/span><\/h2>
If you took the time to read <\/span>Automatically Merge Models Locally and in CI Pipeline - MATLAB & Simulink<\/span><\/a>, you hopefully noticed this note:<\/span><\/div>
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For example, let's say I have a library where a different block has been added at the top level in two branches:<\/span><\/div>
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The auto-merge will fail when trying to merge branch B after having merged branch A.<\/span><\/div>
$ git merge devB<\/span><\/span><\/div>
Auto-merging simpleMdl.slx<\/span><\/span><\/div>
CONFLICT (content): Merge conflict in simpleMdl.slx<\/span><\/span><\/div>
Automatic merge failed; fix conflicts and then commit the result.<\/span><\/span><\/div><\/div>
In that case, you will need to launch MATLAB. In R2025a, you can use the new Source Control panel and select View Conflicts:<\/span><\/div>
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This will launch the <\/span>Three-Way Merge tool<\/span><\/a>. In this simple case, the tool will be able to automatically do the merge, so all you have to do is click <\/span>Apply & Close<\/span>.<\/span><\/div>
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The changes have been merged and are now ready to commit.<\/span><\/div>
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Now it's your turn<\/span><\/h2>
Are you having success merging Simulink models? Let us know in the comments below.<\/span><\/div>
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