How to avoid composer discard changes message

Question

I'm updating symfony verdors via composer. I always do it using:

php composer.phar update

But recent version of composer, before update each package show a message like this:

  - Updating doctrine/data-fixtures dev-master (a95d783 => a28b6bd)
The package has modified files:
M .gitignore
M .gitmodules
M LICENSE
M README.md
M UPGRADE
M composer.json
M lib/Doctrine/Common/DataFixtures/AbstractFixture.php
M lib/Doctrine/Common/DataFixtures/DependentFixtureInterface.php
M lib/Doctrine/Common/DataFixtures/Event/Listener/MongoDBReferenceListener.php
M lib/Doctrine/Common/DataFixtures/Event/Listener/ORMReferenceListener.php

-10 more files modified, choose "v" to view the full list Discard changes [y,n,v,s,?]?

How to avoid this?

Solution 1

Set composer config to discard changes (see: https://github.com/composer/composer/pull/1188):

php composer.phar config --global discard-changes true

Solution 2

both @lemats and @reza-sanaie's answers are incomplete as --no-interaction (-n) composer's option is required to have a real update without any question (see https://github.com/composer/composer/pull/1188#issuecomment-16011533).

So after

php composer.phar config --global discard-changes true

or after modifying composer.json

"config": {
    "discard-changes": true
},  

use

php composer.phar update -n

Solution 3

Alternative to @lemats solution you can modify the composer.json file with:

  "config": {
      "discard-changes": true
  },  

It's worth nothing for this option to kick in you have to be running in --no-interaction mode

php composer.json install --no-interaction

Although I agree with @Seldaek on you shouldn't be modifying these vendor files, but sometimes you are forced to monkey patch it :(

Comments

[Ascherer]

still happens sometimes. I've seen people with servers that chmod on crontab that mess with the perms of all the vendors. or when debugging a vendor lib, it can happen too

[Gabriel Alack]

You could always do a pull request to the vendor repo if it is an important fix

[gidmanma]

This can also happen because of git filemode, especially when the vendor file is something you have symlinked in bin.

[HappyCoder]

And bug testing, sometimes you need to var dump in the vendor files to see what on earth is going on... and you may not always put the changes back 'exactly' as they were... maybe a space is added etc.

[user3399101]

some projects (e.g . Drupal 9.x) modify both checkout files and vendor files, it can't always be avoided.