Proposing a Change
Screencast
Do you prefer video tutorials? Check out the Contributing Back To Symfony screencast series.
A pull request, "PR" for short, is the best way to provide a bug fix or to propose enhancements to Symfony.
Step 1: Check existing Issues and Pull Requests
Before working on a change, check to see if someone else also raised the topic or maybe even started working on a PR by searching on GitHub.
If you are unsure or if you have any questions during this entire process,
please ask your questions on the #contribs
channel on Symfony Slack.
Step 2: Setup your Environment
Install the Software Stack
Before working on Symfony, setup a friendly environment with the following software:
- Git;
- PHP version 7.2.5 or above.
Configure Git
Set up your user information with your real name and a working email address:
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$ git config --global user.name "Your Name"
$ git config --global user.email you@example.com
Tip
If you are new to Git, you are highly recommended to read the excellent and free ProGit book.
Tip
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.
Tip
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:
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$ 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:
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$ 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);
- Uncheck the "Copy the
X.Y
branch only"; - After the "forking action" has completed, clone your fork locally
(this will create a
symfony
directory):
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$ git clone git@github.com:USERNAME/symfony.git
- Add the upstream repository as a remote:
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$ cd symfony
$ git remote add upstream https://github.com/symfony/symfony.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 3: Work on your Pull Request
The License
Before you start, you should be aware that all the code you are going to submit must be released under the MIT license.
Choose the right Branch
Before working on a PR, you must determine on which branch you need to work:
- 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, pick the oldest concerned maintained
branch (you can find them on the Symfony releases page). E.g. if you
found a bug introduced in
v5.1.10
, you need to work on5.4
. 7.1
, if you are adding a new feature.The only exception is when a new major Symfony version (5.0, 6.0, etc.) comes out every two years. Because of the special development process of those versions, you need to use the previous minor version for the features (e.g. use
5.4
instead of6.0
, use6.4
instead of7.0
, etc.)
Note
All bug fixes merged into maintenance branches are also merged into more
recent branches on a regular basis. For instance, if you submit a PR
for the 5.4
branch, the PR will also be applied by the core team on
all the 6.x
branches that are still maintained.
Create a Topic Branch
Each time you want to work on a PR for a bug or on an enhancement, create a topic branch:
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$ git checkout -b BRANCH_NAME 5.x
Or, if you want to provide a bug fix for the 5.4
branch, first track the remote
5.4
branch locally:
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$ git checkout --track origin/5.4
Then create a new branch off the 5.4
branch to work on the bug fix:
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$ git checkout -b BRANCH_NAME 5.4
Tip
Use a descriptive name for your branch (fix_XXX
where XXX
is the
issue 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.
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$ 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.
Tip
If symlinks to your local Symfony fork cannot be resolved inside your project due to
your dev environment (for instance when using Vagrant where only the current project
directory is mounted), you can alternatively use the --copy
option.
When finishing testing your Symfony code into your project, you can use
the --rollback
option to make your project back to its original dependencies.
Work on your Pull Request
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) -- PRs 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: Start by a short subject line (the first line), followed by a blank line and a more detailed description.
The subject line should start with the Component, Bridge or Bundle you are working on in square brackets (
[DependencyInjection]
,[FrameworkBundle]
, ...).Then, capitalize the sentence, do not end with a period, and use an imperative verb to start.
Here is a full example of a subject line:
[MagicBundle] Add `MagicConfig` that allows configuring things
.
Prepare your Pull Request for Submission
When your PR 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 4: Submit your Pull Request
Whenever you feel that your PR is ready for submission, follow the following steps.
Rebase your Pull Request
Before submitting your PR, update your branch (needed if it takes you a while to finish your changes):
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$ git checkout 6.x
$ git fetch upstream
$ git merge upstream/6.x
$ git checkout BRANCH_NAME
$ git rebase 6.x
Tip
Replace 6.x
with the branch you selected previously (e.g. 5.4
)
if you are working on a bug fix.
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:
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$ git add ... # add resolved files
$ git rebase --continue
Check that all tests still pass and push your branch remotely:
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$ git push --force origin BRANCH_NAME
Make a Pull Request
You can now make a pull request on the symfony/symfony
GitHub repository.
Tip
Take care to point your pull request towards symfony:5.4
if you want
the core team to pull a bug fix based on the 5.4
branch.
To ease the core team work, always include the modified components in your pull request message, like in:
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[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 "Issues";
- 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 PR must contain updates to the
relevant
CHANGELOG
andUPGRADE
files; - If you answer yes to "Deprecations?", the PR must contain updates to the
relevant
CHANGELOG
andUPGRADE
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:
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- [ ] 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:
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- [ ] 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 detail 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.
Step 5: Receiving Feedback
We ask all contributors to follow some best practices to ensure a constructive feedback process.
If you think someone fails to keep this advice in mind and you want another
perspective, please join the #contribs
channel on Symfony Slack. If you
receive feedback you find abusive please contact the
CARE team.
The core team is responsible for deciding which PR gets merged, so their feedback is the most relevant. So do not feel pressured to refactor your code immediately when someone provides feedback.
Automated Feedback
There are many automated scripts that will provide feedback on a pull request.
fabbot
fabbot will review code style, check for common typos and make sure the git history looks good. If there are any issues, fabbot will often suggest what changes that should be done. Most of the time you get a command to run to automatically fix the changes.
It is rare, but fabbot could be wrong. One should verify if the suggested changes make sense and that they are related to the pull request.
Psalm
Psalm will make a comment on a pull request if it discovers any potential
type errors. The Psalm errors are not always correct, but each should be reviewed
and discussed. A pull request should not update the Psalm baseline nor add @psalm-
annotations.
After the Psalm phar is installed, the analysis can be run locally with:
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$ psalm.phar src/Symfony/Component/Workflow
Automated Tests
A series of automated tests will run when submitting the pull request. These test the code under different conditions, to be sure nothing important is broken. Test failures can be unrelated to your changes. If you think this is the case, you can check if the target branch has the same errors and leave a comment on your PR.
Otherwise, the test failure might be caused by your changes. The following test scenarios run on each change:
PHPUnit / Tests
-
This job runs on Ubuntu using multiple PHP versions (each in their own job). These jobs run the testsuite just like you would do locally.
A failure in these jobs often indicates a bug in the code.
PHPUnit / Tests (high-deps)
-
This job checks each package (bridge, bundle or component) in
src/
individually by callingcomposer update
andphpunit
from inside each package.A failure in this job often indicates a missing package in the
composer.json
of the failing package (e.g.src/Symfony/Bundle/FrameworkBundle/composer.json
).This job also runs relevant packages using a "flipped" test (indicated by a
^
suffix in the package name). These tests checkout the previous major release (e.g.5.4
for a pull requests on6.3
) and run the tests with your branch as dependency.A failure in these flipped tests indicate a backwards compatibility break in your changes.
PHPUnit / Tests (low-deps)
-
This job also checks each package individually, but then uses
composer update --prefer-lowest
before running the tests.A failure in this job often indicates a wrong version range or a missing package in the
composer.json
of the failing package. continuous-integration/appveyor/pr
-
This job runs on Windows using the x86 architecture and the lowest supported PHP version. All tests first run without extra PHP extensions. Then, all skipped tests are run using all required PHP extensions.
A failure in this job often indicate that your changes do not support Windows, x86 or PHP with minimal extensions.
Integration / Tests
-
Integration tests require other services (e.g. Redis or RabbitMQ) to run. This job only runs the tests in the
integration
PHPUnit group.A failure in this job indicates a bug in the communication with these services.
PHPUnit / Tests (experimental)
- This job always passes (even with failing tests) and is used by the core team to prepare for the upcoming PHP versions.
Rework your Pull Request
Based on the feedback on the pull request, you might need to rework your
PR. Before re-submitting the PR, rebase with upstream/6.x
or
upstream/5.4
, don't merge; and force the push to the origin:
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$ git rebase -f upstream/6.x
$ git push --force origin BRANCH_NAME
Note
When doing a push --force
, always specify the branch name explicitly
to avoid messing other branches in the repository (--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.