Error when running ``poetry install`` in a new (empty) project.

• 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: Debian buster

• Poetry version: 0.12.10

Issue

I was setting up a project, first I added some dependencies via poetry add (and I didn’t add any actual code). Then I issued poetry install which resulted in stacktrace below.

It turns out I had empty directory named like the package (in poetry.toml below package name is “test” and I had empty directory named test). It looks like it triggered a bug in find_packages. When I added some code to test package bug went away.

Error stacktrace

[IndexError]  
list index out of range    
	                     
Exception trace:
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/cleo/application.py in run() at line 94
   status_code = self.do_run(input_, output_)
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/poetry/console/application.py in do_run() at line 88
   return super(Application, self).do_run(i, o)
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/cleo/application.py in do_run() at line 197
   status_code = command.run(input_, output_)
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/poetry/console/commands/command.py in run() at line 77
   return super(BaseCommand, self).run(i, o)
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/cleo/commands/base_command.py in run() at line 146
   status_code = self.execute(input_, output_)
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/cleo/commands/command.py in execute() at line 107
   return self.handle()
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/poetry/console/commands/install.py in handle() at line 86
   f.write(decode(builder.build_setup()))
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/poetry/masonry/builders/sdist.py in build_setup() at line 125
   pkg_dir, _packages, _package_data = self.find_packages(include)
 /opt/venvs/poetry-0.12.10/lib/python3.7/site-packages/poetry/masonry/builders/sdist.py in find_packages() at line 237
   base = str(include.elements[0].parent)

poetry.toml

[tool.poetry]
name = "test"
version = "0.1.0"
description = ""
authors = ["Jacek Bzdak <[e-mail]>"]

[tool.poetry.dependencies]
python = "^3.7"
six = "^1.11"

[tool.poetry.dev-dependencies]

[build-system]
requires = ["poetry>=0.12"]
build-backend = "poetry.masonry.api"

[seansfkelley]

A use-case for running install in an otherwise empty project is to improve caching behavior of Docker builds: I copy pyproject.toml and poetry.lock, then install, then copy in all the project source. I had to add an extra step to drop an empty file so Poetry wouldn’t explode when I did this:

RUN touch /path/to/project/.empty

Edit: though I guess I could just… not create the empty directory in the first place. That also works…

[Arkelis]

It seems that this error occurs when Poetry tries to install the current project’s package; a workaround is to specify --no-root when installing the depedencies if the project-named directory is empty. We could raise ModuleOrPackageNotFound instead of ValueError as the former is handled by the install command.