Poetry cannot find and install package with 0.???a (alpha/beta designation) in its version

• 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: Oracle Linux Server 7.5

• Poetry version: 0.12.11

• Link of a Gist with the contents of your pyproject.toml file: Proprietary!

Issue

When trying to add “bit-vector” package, I get this error:

$ poetry add bit-vector
                                                        
[ValueError]                                
Could not find a matching version of package bit-vector  

add [-D|--dev] [--git GIT] [--path PATH] [-E|--extras EXTRAS] [--optional] [--python PYTHON] [--platform PLATFORM] [--allow-prereleases] [--dry-run] [--] <name> (<name>)...

poetry search bit-vector shows:

bit-vector (0.42a0)
 A BitVector class for Python

Editing the .toml file and adding ‘bit-vector = “0.26a0”’ works, but poetry show --outdated does not show new “0.42a0” version nor, poetry update updates to this version.

[pawamoy]

Just a note: poetry could print a message like If the package you try to install is in alpha/beta, try with the --allow-prereleases flag when the command fails. Currently, people experiencing this issue must come here on the issue tracker and search for this problem to get the solution, which is not efficient. Sometimes they will even open duplicate issues 😅 A simple message could help reduce this.

$ poetry add sty

[ValueError]                         
Could not find a matching version of package sty
If the package you want to install is in alpha/beta, try with the --allow-prereleases flag  

add [-D|--dev] [--git GIT] [--path PATH] [-E|--extras EXTRAS] [--optional] [--python PYTHON] [--platform PLATFORM] [--allow-prereleases] [--dry-run] [--] <name> (<name>)...

[woile]

Have you tried adding the --allow-prereleases flag?