Create a patch for a Magento 2 Composer installation from a GitHub commit

Sometimes it takes a while for the Magento Engineering Team to include a bug fix made on GitHub in a Magento 2 Composer release. In the meantime, you can create a patch from GitHub and use the cweagans/composer-patches plugin to apply it to your Composer-based Magento 2 installation.

Warning: Always perform comprehensive testing before deploying any unreleased patch.

Create a patch

There are many ways to create patch files. The example below focuses on creating a patch from a known commit.

To create a patch file, follow these steps:

1. Create a patches/composer directory in your local project.
2. Identify the GitHub commit or pull request to use for the patch. This example uses the 2d31571 commit, linked to Magento 2 GitHub issue #6474.
3. Append the .patch or the .diff extensions to the commit URL. Use .diff for smaller file size. For example:
   https://github.com/magento/magento2/commit/2d31571f1bacd11aa2ec795180abf682e0e9aede.diff
   
   
4. Save the page as a file in the patches/composer directory. For example, github-issue-6474.diff.
5. Edit the file and remove app/code/<VENDOR>/<PACKAGE> from all paths so that they are relative to the vendor/<VENDOR>/<PACKAGE> directory.

The following example shows the previously mentioned diff file after removing all instances of app/code/Magento/Payment:

diff --git a/view/frontend/web/js/view/payment/iframe.js b/view/frontend/web/js/view/payment/iframe.js
index c8a6fef58d31..7d01c195791e 100644
--- a/view/frontend/web/js/view/payment/iframe.js
+++ b/view/frontend/web/js/view/payment/iframe.js
@@ -154,6 +154,7 @@ define(
              */
             clearTimeout: function () {
                 clearTimeout(this.timeoutId);
+                this.fail();

                 return this;
             },

Text editors that automatically remove trailing whitespace or add new lines can break the patch. Use a simple text editor to make these changes.

Apply a patch

To apply a patch, follow these steps:

1. Open your command line application and navigate to your project directory.
2. Add the cweagans/composer-patches plugin to the composer.json file.
   

   composer require cweagans/composer-patches

3. Edit the composer.json file and add the following section to specify:
   • Module: "magento/module-payment"
   • Title: "MAGETWO-56934: Checkout page freezes when ordering with Authorize.net with invalid credit card"
   • Path to patch: "patches/composer/github-issue-6474.diff"
   For example:

   "extra": {
       "composer-exit-on-patch-failure": true,
       "patches": {
           "magento/module-payment": {
               "MAGETWO-56934: Checkout page freezes when ordering with Authorize.net with invalid credit card": "patches/composer/github-issue-6474.diff"
           }
       }
   }
   

   If a patch affects multiple modules, you must create multiple patch files targeting multiple modules.
   
   
4. Apply the patch. Use the -v option only if you want to see debugging information.
   

   composer -v install

5. Update the composer.lock file. The lock file tracks which patches have been applied to each Composer package in an object.
   

   composer update --lock