How to check in CI if any Composer dependency can be upgraded, using a committed file as a way to ignore upgrades blocked by external factors.

composer-outdated.sh

#!/usr/bin/env bash

rm outdated-status.txt
touch outdated-status.txt

for package in `composer outdated | awk '{ print $1":"$4 }'`; 
do
    echo "New version: $package" > outdated-status.txt
    composer why-not $package > outdated-status.txt
    echo "----------"  > outdated-status.txt
done

if [ -z $(git status --porcelain) ];
then
    echo "Nothing changed"
    exit 0;
else
    echo "SOMETHING CHANGED, PLEASE UPDATE DEPS!"
    git diff
    exit 1
fi

I've fixed a thing: the file must be erased first, and appendend only after.