How to solve Magento 2 upgrade errors

Magento 2 is the leading Open Source Software for e-commerce, with a vibrant community and proper product documentation.

The development team releases bug fixes and new features in a regular cadence, given support to security threats, market trends, amongst others.

Environment

The environment is deployed in AWS, using an immutable infrastructure. It allows us to deploy several development/testing environments where we can develop the scripts to automate the upgrade process for our CI/CD pipeline. Also, it is our workbench for testing UI changes, new plugins, amongst others.

Upgrading

However, trying to upgrade to the latest version (at the moment of writing this post is 2.2.3), using the official documentation, we receive the following error:

Magento 2 upgrade command - failed to open stream error

This is annoying. So far, we had reliable platform upgrades. Using my developer hat, we followed the error. A file was missing in the magento 2 installation path\setup\ folder.

Doing a quick search with the ls command, we had the folder structure:

Magento 2 root folder - after the ls command

The code never lies. The setup/ folder doesn’t exist. It intrigued us, getting us to investigate why the folder wasn’t there. We verified:

• The official GitHub repo. The setup/ folder exists, and it has content
• Download the official Magento 2 Full Release, inspecting the contents. Again, the setup/ folder exists, and it has content
• Deploy a new AWS development environment with the current infrastructure, inspecting the folder structure. The setup/ folder exists in the current installation

Magento 2 root folder - current installation

Given the information from our investigation, it seemed to point out to the PHP Composer, which doesn’t deploy the setup/ folder during the upgrade process. To prove it, we tried to upgrade the environment again, using the same commands:

Magento 2 composer - update command

And we were able to reproduce the initial error. At least it is reproducible and supports our theory. :)

The (temporary) solution

Since the PHP Composer package should contain (apart from the metadata file) the same files as  the downloadable Magento 2 installation package, we’ve tried to:

• Follow the upgrade steps from the official guide until step 6 (Update the database schema and data)
• Download the Magento 2 installation package
• Extract the setup/ folder to the Magento 2 installation folder
• Resume the Magento 2 upgrade process

And voilá, it finished the Magento 2 upgrade to the version 2.2.3. Happy days, we can do our testing on the new version of the shop, before promoting it to production.

This error had been reported to the Magento development team, however, they can’t reproduce it. Nevertheless, we can use this workaround to upgrade our (your) shop.