Source code management

The main source code management tool for the FreeCAD project is Git, which can be easily installed in most operating systems from a package manager or directly from Git's website. You are advised to become familiar with Git before working with the FreeCAD source code directly. Visit the Git documentation page for the reference manual as well as tutorials to learn to use the system. The present article explains how to use Git with FreeCAD.

While Git is primarily a terminal application, there are many graphical clients for it which facilitate working with branches, applying patches, and submitting pull requests to a master branch. Examples include git-cola, gitg, and GitKraken. Please see Developing FreeCAD with GitKraken for a cursory introduction to this tool.

Source code access
Everybody can access and get a copy of the FreeCAD source code, but only the FreeCAD project managers have write access to it. You can get a copy of the code, study it and modify it as you wish. If you want your changes to be included in the official source code, you need to perform a pull request against the master repository so that your modifications can be reviewed by one of the managers.

If your source code changes are significant, you are advised to explain them in the pull request section of the FreeCAD forum.

Official GitHub repository
The FreeCAD source code is hosted in Github, https://github.com/FreeCAD/FreeCAD

In order to contribute code, you need to have a GitHub account.

Setting your git username
Developers should commit code to their personal repository using their GitHub username. If that is not already set globally, you can set it locally for the current Git repository like this:

Where represents your full name or nickname, used to identify the author of a particular commit, and  indicates your GitHub username.

You can now use some combination of and  to create one or more commits in your local repository.

Remote repositories
Please read What is the difference between origin and upstream on GitHub? (Stackoverflow) to help you understand the difference between and  in the context of Git. This section explains how to set the correct repositories for development. Essentially:
 * is your personal fork of the official FreeCAD repository, that is,
 * is the official FreeCAD repository, that is, https://github.com/FreeCAD/FreeCAD

This distinction is important, as you should push code to your own copy of the repository first, before pushing those changes to the official repository. If you clone from the repository, the  remote repository will point to the official repository. If you accidentally did this, you can use to change the name of this remote to.

Based on the above, there are two ways to setup your Git development environment:
 * 1st Method: Fork on GitHub and clone your fork locally
 * 2nd Method: Clone FreeCAD directly to your local machine

We recommend the 1st method because it's one step faster.

1st Method: Fork on GitHub and clone your fork locally
First you will fork the FreeCAD repository in GitHub, then clone this personal fork to your computer, and finally set the repository.
 * Log in to your GitHub account.
 * Go to the official FreeCAD repository: https://github.com/FreeCAD/FreeCAD
 * In the top right of the page press the "Fork" button. This will create a personal copy of the FreeCAD repository under your GitHub username:
 * On your machine, clone your newly created FreeCAD fork. It will be created inside a directory.


 * Once the download is complete, enter the new source directory and set the repository.


 * Confirm your remote repositories with ; the output should be similar to this


 * Now development can begin. See Git Development Process.

2nd Method: Clone FreeCAD directly to your local machine
First you will fork the FreeCAD repository in GitHub, however, you will clone the original FreeCAD repository to your local machine, and then alter your remotes via the terminal.
 * Log in to your GitHub account.
 * Go to the official FreeCAD repository: https://github.com/FreeCAD/FreeCAD
 * In the top right of the page press the "Fork" button. This will create a personal copy of the FreeCAD repository under your GitHub username:
 * Clone the original FreeCAD repository. It will be created inside a directory.


 * Once the download is complete, enter the new source directory and set the repository.


 * Then set up the repository.


 * Confirm your remote repositories with ; the output should be similar to this


 * Now development can begin. See Git Development Process.

Branching
Best practices recommend creating a new branch whenever you want to work on a new feature. Creating a new branch is done in two steps, first your create the branch, and then you switch to it:

Alternatively, use a single instruction:

To see the branches in your project and the current branch you are using type

Committing
Once you are inside a new branch, edit the source files that you want. When you are ready to commit the changes issue

Unlike SVN, you need to specifically tell which files to commit; use the option to commit changes in all files that were changed. Your text editor will open to allow you to write a commit message.

Writing good commit messages
You should try to work in small chunks. If you cannot summarize your changes in one sentence, then it has probably been too long since you have made a commit.

For big changes, it is important that you have helpful and useful descriptions of your work. FreeCAD has adopted a format mentioned in book Pro Git.

If you are doing a lot of related work in a branch, you should make as many commits as it makes sense (see a forum post). When you want to merge those changes into the master branch, you should issue

to see the individual commit messages. Then you can write a high quality message for the merge message.

When you merge to master use the option and commit with your quality commit message. This will allow you to be very liberal with your commits and help to provide a good level of detail in commit messages without so many distinct descriptions.

Pushing your work to your GitHub repository
After you've correctly committed modifications to your local branch in your computer, you can push this branch to your remote git server, that is,. This opens your branch to the public online, and allows other developers to review and integrate this branch into the official FreeCAD master branch.

Please read Pushing commits to a remote repository for more information.

Check out GitHub requests locally
Checkout GitHub pull requests locally

Resolving merge conflicts

 * How merge conflicts are presented.
 * Resolving a merge conflict using the command line.
 * External merge and diff tools to use when you encounter a Git conflict.

Creating patches from git
Although Git allows you to merge different branches of code quickly, there are times when it may be desirable to create a patch instead of merging or performing a pull request. The following workflow explains how to do this.


 * You should be developing your new code in a secondary branch of your repository, and not in the master branch. So the first step is to make sure you are in the correct branch.


 * Now use against the master branch, and use the  option to redirect the result to standard output; then redirect the standard output to a file, which for convenience is created above the source code directory.


 * Another method is

The number of circumflex carets or the number  indicate the number of commits that should be considered, that is,  or  will create three patches for three commits.

This will create a patch or series of patches with the following naming convention

where is a number from  to, and the commit message forms the majority of the file name, for example,

Applying patches via git
Git can merge patches or diffs. To know more about this process read Applying patches with Git.

If you already have the patch file in your system, just apply it.

You can use to download a patch from a website, and then apply it through.

Add or  at the end of the URL of a GitHub commit, pull request, or compare view so that the website shows you the plain text view of that page.
 * Regular commit page: https://github.com/FreeCAD/FreeCAD/commit/c476589652a0f67b544735740e20ff702e8d0621
 * Diff page: https://github.com/FreeCAD/FreeCAD/commit/c476589652a0f67b544735740e20ff702e8d0621.diff
 * Patch page: https://github.com/FreeCAD/FreeCAD/commit/c476589652a0f67b544735740e20ff702e8d0621.patch

You can point to a particular commit patch in the repository, and pipe it directly to  to apply the patch. curl https://github.com/FreeCAD/FreeCAD/commit/c476589652a0f67b544735740e20ff702e8d0621.patch | git apply -

Reversing a patch in git
When you apply a patch you modify some files. However, these modifications aren't permanent until you commit the changes. Therefore, if you want to revert a patch use the following instructions.

This will revert the changes applied, if you still have access to the original patch file.

Alternatively, this will remove non-committed changes to the branch.

Stashing git commits
Say that you're working on a branch and you find yourself making some modifications to the source that are out of the scope of your current branch; in other words, those changes would be better in another branch instead of the current one. The command can be used to temporarily store those uncommitted local changes.

If in the future you want to use those commits, you can apply the stash.

Or if you decide that you don't like the commits anymore, you may delete the stash.

You can list multiple stashes with

To learn more, read Useful tricks you might not know about Git stash.

FreeCAD revision number
In contrast to subversion, which uses a consecutive number for its revisions, Git produces SHA-1 hash values with every commit. A hash value is a long alphanumeric string that looks like this

Latest revision number
To find the latest revision number of a particular branch use the operation with the  option.

Or browse the repository on GitHub, and read the amount of commits reported in the particular branch.

Revision number of a specific commit hash
Since the hash is an alphanumeric string it is not very useful to decide if a certain commit is older or newer than another hash. To find the revision number of a particular hash, again use the operation; the input can be the full hash, or a partial hash that is unique, usually the first 7 digits are enough.

Revision hash of a specific commit number
If we have the commit number, say, 15000, and we want to find the corresponding hash, we need to calculate the number of commits since this point until the last commit. First, get the latest commit number.

Then subtract the commit that we want.

Then use the operation to show all commits and hashes. The option jumps the difference in commits that we calculated so that we go directly to the hash that we are looking for.

Confirm it's the right commit number.


 * Show the commits starting from a particular commit in GitHub: in the address bar of the browser, change the word to  to show a list.
 * Finding the revision number of the commit
 * Finding the revision number of the commit
 * Finding the corresponding hash value to a particular commit number

Revision number in FreeCAD's interface
The version number that appears in is defined in, which is created at compile time when the  tool is run. Read Extract version number from git source for more information.

See the compile on Unix page for the full information on compiling FreeCAD.

Alternative repositories
The beauty of git is that everybody can clone a project, and start modifying the code. Several frequent collaborators of the FreeCAD project have their own git repository, where they build up their work before it is ready to be included in the official source code, or simply where they experiment new ideas. In certain cases, you might want to clone your FreeCAD code from one of these, instead of the official repos, to benefit from the changes their users did.

Be warned, though, that this is at your own risk, and only the official repository above is fully guaranteed to work and contain clean code.

It is also possible to attach several remote repositories to a same local FreeCAD git code, using the "git remote" command. This is useful to keep in sync with the master code branch, but keep an eye on the work of different developers.