Support "standard" square bracket syntax for package extras

• I have searched the issues of this repo and believe that this is not a duplicate.

Issue

It would be great if poetry would support the “standard” square bracket syntax to specify package extras (i.e. somepackage[someextra]).

I’m aware of the -E option but it’s a departure from what other tools are doing and also it’s not immediately clear how to specify multiple different extras for multiple packages.

[JulianFerry]

For anyone stumbling on this with the same issue as me:

• poetry add apache-beam[gcp] errors with zsh: no matches found: apache-beam[gcp]
• Writing poetry add "apache-beam[gcp]" fixed this

[clintonroy]

If you try:

poetry add testcontainers[postgresql]

You’ll get:

testcontainers = {extras = ["postgresql"], version = "^2.6.0"}