Submitting a Patch

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Read the updated version of this page for Symfony 6.2 (the current stable version).

Submitting a Patch

Patches are the best way to provide a bug fix or to propose enhancements to Symfony.

Step 1: Setup your Environment

Install the Software Stack

Before working on Symfony, setup a friendly environment with the following software:

  • Git;
  • PHP version 5.5.9 or above.

Configure Git

Set up your user information with your real name and a working email address:

$ git config --global "Your Name"
$ git config --global


If you are new to Git, you are highly recommended to read the excellent and free ProGit book.


If your IDE creates configuration files inside the project's directory, you can use global .gitignore file (for all projects) or .git/info/exclude file (per project) to ignore them. See GitHub's documentation.


Windows users: when installing Git, the installer will ask what to do with line endings, and suggests replacing all LF with CRLF. This is the wrong setting if you wish to contribute to Symfony! Selecting the as-is method is your best choice, as Git will convert your line feeds to the ones in the repository. If you have already installed Git, you can check the value of this setting by typing:

$ git config core.autocrlf

This will return either "false", "input" or "true"; "true" and "false" being the wrong values. Change it to "input" by typing:

$ git config --global core.autocrlf input

Replace --global by --local if you want to set it only for the active repository

Get the Symfony Source Code

Get the Symfony source code:

  • Create a GitHub account and sign in;
  • Fork the Symfony repository (click on the "Fork" button);
  • After the "forking action" has completed, clone your fork locally (this will create a symfony directory):
$ git clone
  • Add the upstream repository as a remote:
$ cd symfony
$ git remote add upstream git://

Check that the current Tests Pass

Now that Symfony is installed, check that all unit tests pass for your environment as explained in the dedicated document.

Step 2: Work on your Patch

The License

Before you start, you must know that all the patches you are going to submit must be released under the MIT license, unless explicitly specified in your commits.

Choose the right Branch

Before working on a patch, you must determine on which branch you need to work:

  • 2.8, if you are fixing a bug for an existing feature or want to make a change that falls into the list of acceptable changes in patch versions (you may have to choose a higher branch if the feature you are fixing was introduced in a later version);
  • master, if you are adding a new feature.


All bug fixes merged into maintenance branches are also merged into more recent branches on a regular basis. For instance, if you submit a patch for the 2.8 branch, the patch will also be applied by the core team on the master branch.

Create a Topic Branch

Each time you want to work on a patch for a bug or on an enhancement, create a topic branch:

$ git checkout -b BRANCH_NAME master

Or, if you want to provide a bugfix for the 2.8 branch, first track the remote 2.8 branch locally:

$ git checkout -t origin/2.8

Then create a new branch off the 2.8 branch to work on the bugfix:

$ git checkout -b BRANCH_NAME 2.8


Use a descriptive name for your branch (ticket_XXX where XXX is the ticket number is a good convention for bug fixes).

The above checkout commands automatically switch the code to the newly created branch (check the branch you are working on with git branch).

Use your Branch in an Existing Project

If you want to test your code in an existing project that uses symfony/symfony or Symfony components, you can use the link utility provided in the Git repository you cloned previously. This tool scans the vendor/ directory of your project, finds Symfony packages it uses, and replaces them by symbolic links to the ones in the Git repository.

$ php link /path/to/your/project

Before running the link command, be sure that the dependencies of the project you want to debug are installed by running composer install inside it.

Work on your Patch

Work on the code as much as you want and commit as much as you want; but keep in mind the following:

  • Read about the Symfony conventions and follow the coding standards (use git diff --check to check for trailing spaces -- also read the tip below);
  • Add unit tests to prove that the bug is fixed or that the new feature actually works;
  • Try hard to not break backward compatibility (if you must do so, try to provide a compatibility layer to support the old way) -- patches that break backward compatibility have less chance to be merged;
  • Do atomic and logically separate commits (use the power of git rebase to have a clean and logical history);
  • Never fix coding standards in some existing code as it makes the code review more difficult;
  • Write good commit messages (see the tip below).


When submitting pull requests, fabbot checks your code for common typos and verifies that you are using the PHP coding standards as defined in PSR-1 and PSR-2.

A status is posted below the pull request description with a summary of any problems it detects or any Travis CI build failures.


A good commit message is composed of a summary (the first line), optionally followed by a blank line and a more detailed description. The summary should start with the Component you are working on in square brackets ([DependencyInjection], [FrameworkBundle], ...). Use a verb (fixed ..., added ..., ...) to start the summary and don't add a period at the end.

Prepare your Patch for Submission

When your patch is not about a bug fix (when you add a new feature or change an existing one for instance), it must also include the following:

  • An explanation of the changes in the relevant CHANGELOG file(s) (the [BC BREAK] or the [DEPRECATION] prefix must be used when relevant);
  • An explanation on how to upgrade an existing application in the relevant UPGRADE file(s) if the changes break backward compatibility or if you deprecate something that will ultimately break backward compatibility.

Step 3: Submit your Patch

Whenever you feel that your patch is ready for submission, follow the following steps.

Rebase your Patch

Before submitting your patch, update your branch (needed if it takes you a while to finish your changes):

$ git checkout master
$ git fetch upstream
$ git merge upstream/master
$ git checkout BRANCH_NAME
$ git rebase master


Replace master with the branch you selected previously (e.g. 2.8) if you are working on a bugfix

When doing the rebase command, you might have to fix merge conflicts. git status will show you the unmerged files. Resolve all the conflicts, then continue the rebase:

$ git add ... # add resolved files
$ git rebase --continue

Check that all tests still pass and push your branch remotely:

$ git push --force origin BRANCH_NAME

Make a Pull Request

You can now make a pull request on the symfony/symfony GitHub repository.


Take care to point your pull request towards symfony:2.8 if you want the core team to pull a bugfix based on the 2.8 branch.

To ease the core team work, always include the modified components in your pull request message, like in:

[Yaml] fixed something
[Form] [Validator] [FrameworkBundle] added something

The default pull request description contains a table which you must fill in with the appropriate answers. This ensures that contributions may be reviewed without needless feedback loops and that your contributions can be included into Symfony as quickly as possible.

Some answers to the questions trigger some more requirements:

  • If you answer yes to "Bug fix?", check if the bug is already listed in the Symfony issues and reference it/them in "Fixed tickets";
  • If you answer yes to "New feature?", you must submit a pull request to the documentation and reference it under the "Doc PR" section;
  • If you answer yes to "BC breaks?", the patch must contain updates to the relevant CHANGELOG and UPGRADE files;
  • If you answer yes to "Deprecations?", the patch must contain updates to the relevant CHANGELOG and UPGRADE files;
  • If you answer no to "Tests pass", you must add an item to a todo-list with the actions that must be done to fix the tests;
  • If the "license" is not MIT, just don't submit the pull request as it won't be accepted anyway.

If some of the previous requirements are not met, create a todo-list and add relevant items:

- [ ] fix the tests as they have not been updated yet
- [ ] submit changes to the documentation
- [ ] document the BC breaks

If the code is not finished yet because you don't have time to finish it or because you want early feedback on your work, add an item to todo-list:

- [ ] finish the code
- [ ] gather feedback for my changes

As long as you have items in the todo-list, please prefix the pull request title with "[WIP]".

In the pull request description, give as much details as possible about your changes (don't hesitate to give code examples to illustrate your points). If your pull request is about adding a new feature or modifying an existing one, explain the rationale for the changes. The pull request description helps the code review and it serves as a reference when the code is merged (the pull request description and all its associated comments are part of the merge commit message).

In addition to this "code" pull request, you must also send a pull request to the documentation repository to update the documentation when appropriate.

Rework your Patch

Based on the feedback on the pull request, you might need to rework your patch. Before re-submitting the patch, rebase with upstream/master or upstream/2.8, don't merge; and force the push to the origin:

$ git rebase -f upstream/master
$ git push --force origin BRANCH_NAME


When doing a push --force, always specify the branch name explicitly to avoid messing other branches in the repo (--force tells Git that you really want to mess with things so do it carefully).

Moderators earlier asked you to "squash" your commits. This means you will convert many commits to one commit. This is no longer necessary today, because Symfony project uses a proprietary tool which automatically squashes all commits before merging.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.