How do I apply patch in vendor directory using composer?

Question

Background:

• Drupal 8
• Managing dependencies with compose

I want to apply one patch to vendor/behat/web_api_extension project.

I tried with this in composer.json but it doesn't works or no error.

"extra": {
    "enable-patching": true,
    "patches": {
        "drupal/better_formats": {
           "Settings have no affect on the field if it is in a Paragraph bundle - https://www.drupal.org/node/2754029": "https://www.drupal.org/files/issues/better_formats_paragraphs-2754029-15.patch"
        },
        "vendor/behat/web-api-extension": {
            "behat web api definition conflicts with mink extensions": "patches/behat_web_api/alter-definitions-text.patch"
        }
    }
}

Answer 1

You will need cweagans vendor to make composer able to parse the extra->patches lines.

This line is wrong I think: "vendor/behat/web-api-extension" You always need the package name (without version) and not the relative path. In your case it should be "behat/behat"

Answer 2

You need to have cweagans/composer-patches as a requirement on your project, so you need to:

composer require cweagans/composer-patches

Then in your composer.json you need to add your patches under extra:patches, which you already had:

...
"extra": {
    "enable-patching": true,
    "patches": {
        "drupal/better_formats": {
           "Settings have no affect on the field if it is in a Paragraph bundle - https://www.drupal.org/node/2754029": "https://www.drupal.org/files/issues/better_formats_paragraphs-2754029-15.patch"
        },
        "vendor/behat/web-api-extension": {
            "behat web api definition conflicts with mink extensions": "patches/behat_web_api/alter-definitions-text.patch"
        }
    }
}
...