• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: macOS Catalina 10.15.6
• Poetry version: 1.1.3
• Link of a Gist with the contents of your pyproject.toml file:

Issue

When I run poetry add scrapy, it raise an error:

[RecursionError]
maximum recursion depth exceeded while calling a Python object

However, when I run poetry shell first to enter the virtual env，and then run poetry add scrapy, then everying works fine.