Holy shit, I *finally* found the solution to the problem I've been having updating our Drupal 8 sites with Composer!!!!
:tada: :champagne: :confetti_ball: :rocket: :disco:
It's not that Composer is somehow corrupted on my computer, it's that our composer.json file is messed up (yeah, the same file drupal.org was recommending back when we started using Composer with D8 :woman-facepalming::skin-tone-3:) and is incompatible with newer versions of Composer. Jason was able to run updates because he must not have updated Composer recently.
Following the instructions at (https://www.drupal.org/project/drupal/issues/3020337), I removed
```
"merge-plugin": {
"include": [
"core/composer.json"
],
"recurse": false,
"replace": false,
"merge-extra": false
},
```
from composer.json in EA on my local. Suddenly, `composer update` was able to run without those insane conflicts!!!
Soooo... @jmickela you were talking about changing how we handle updates in future, and I know you made changes to a couple of sites. Since we're still managing our modules with Composer, we need to add fixing our composer.json to the list of things to do as we switch sites over to updating via Pantheon.
I'd be happy to do that part -- can we talk about it tomorrow?