Problem/Motivation
A standard composer build now complains Skipped installation of bin bin/composer for package composer/composer: file not found in package and results in a dangling link (vendor/bin/composer pointing to nonexistent vendor/composer/composer/bin/composer - even the composer/bin doesn't exist.
This seems to have been introduced in #3057094: Add Composer vendor/ hardening plugin to core
It's discussed in #3057094-131: Add Composer vendor/ hardening plugin to core and demonstrated in, for example, #3057094-90: Add Composer vendor/ hardening plugin to core
You can repro like this:
$ git checkout 8.8.x
$ rm -rf vendor/
$ composer install
You'll then eventually see:
Skipped installation of bin bin/composer for package composer/composer: file not found in package
This error is a little bit of a lie because it does create the symlink even though the file doesn't exist.