Upgrade the project to Symfony 4.0 then to Symfony 4.2

[Yann-BUTSCHER-EIRL]

Context

The differences between Symfony 3.4 and Symfony 4.0 are minor. The deprecated methods in 3.4 just desapear in 4.0 but otherwise the features are the same.

Then we should probably upgrade to 4.2 which is the next LTS version.

The faster we upgrade the project, the lesser code will need to be updated.

Todo

• Upgrade to Symfony 4.0 using this guide : https://symfonycasts.com/screencast/symfony4-upgrade
• Upgrade to Symfony 4.1 using this guide : https://github.com/symfony/symfony/blob/4.1/UPGRADE-4.1.md
• Upgrade to Symfony 4.2 using this guide : https://github.com/symfony/symfony/blob/4.2/UPGRADE-4.2.md
• Other things listed in the comments

[Yann-BUTSCHER-EIRL]

There is no more deprecation warnings when running the project so we could be able to transition to 4.0 easily

[LucileDT]

Saw another interesting thing: we can show Symfony deprecation in unit tests, could you look at the official documentation?

[Yann-BUTSCHER-EIRL]

We already show them but there is no deprecation anymore.

After some testing I realized that we can't upgrade to 4.0 since Mink only support Symfony 2 and 3.
See this : minkphp/Mink#757

From this we have two obvious solutions :

• Upgrade anyway and use something else than Mink for testing
• Keeping the project in Symfony 3.4 for now

We might also try this : https://blog.rafalmuszynski.pl/how-to-configure-behat-with-symfony-4/
But I'm not sure if this will work

[Yann-BUTSCHER-EIRL]

The server has been upgraded in a new branch but there is thing we still need to do :

• Update the documentation (Exported to Update the project documentation #114)
  • Install procedure
  • How to launch the server
  • How to run the tests
• Update sources to use the new flashbag
• Launch Chrome or Chromium automatically when executing tests (exported to Simplify test lauching procedure #113)
• Launch the server in test env automatically when executing tests (exported to Simplify test lauching procedure #113)
• Find a more userfriendly way to run the server

[LucileDT]

I merged the branch on develop

[LucileDT]

I think we should separate the todo list in several issues, this one is too big

[Yann-BUTSCHER-EIRL]

Closing this issue since all the remaining work has been exported to separated issues.