Installing package when depending on parent dir fails when it contains dep to private repo

• I am on the latest Poetry version:
  Tried with both 0.12.16 and 1.0.0a4.
• I have searched the issues of this repo and believe that this is not a duplicate.
  Looks similar to #1026, but not exactly the same.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: macOS Mojave 10.14.5 (18F132) (Darwin nbmbp.local 18.6.0 Darwin Kernel Version 18.6.0: Thu Apr 25 23:16:27 PDT 2019; root:xnu-4903.261.4~2/RELEASE_X86_64 x86_64)
• Poetry version: Tried with both 0.12.16 and 1.0.0a4.
• Link of a Gist with the contents of your pyproject.toml file: https://gist.github.com/nbigaouette-eai/c32900225271601ab4ef25bfa7903093

Issue

I want to add a subdirectory to an existing (private) project (f.e. private-package-from-parent-dir), define a new package there (f.e. subprojectname) and depend on the main private project using path = .. to direct poetry where to find it.

Unfortunately, poetry seems to be confused as to where to find the different dependencies.

The parent project (private-package-from-parent-dir) depends on both packages from pypi.org and a private one (private-package-published-on-privaterepo). The private one has dependencies only to public pypi packages.

Creating the lock in the subproject succeeds, but installing the dependencies fails:

> cd subprojectname
> poetry install -vvv
[...]
[EnvCommandError]
Command ['/Users/nbigaouette/private-package-from-parent-dir.git/subprojectname/.venv/bin/python', '-m', 'pip', 'install', '--no-deps', '-U', '-e', '/Users/nbigaouette/private-package-from-parent-dir.git'] errored with
the following output:
Obtaining file:///Users/nbigaouette/private-package-from-parent-dir.git
  Installing build dependencies: started
  Installing build dependencies: finished with status 'done'
  Getting requirements to build wheel: started
  Getting requirements to build wheel: finished with status 'done'
  Installing backend dependencies: started
  Installing backend dependencies: finished with status 'error'
  ERROR: Complete output from command /Users/nbigaouette/private-package-from-parent-dir.git/subprojectname/.venv/bin/python /Users/nbigaouette/private-package-from-parent-dir.git/subprojectname/.venv/lib/python3.7/site-packages/pip install --ignore-installed --no-user --prefix /private/var/folders/3z/mjcq38mx3610kl4gnt9zw3gw0000gn/T/pip-build-env-zsn9ntu0/normal --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'private-package-published-on-privaterepo>=0.4.0,<0.5.0' 'structlog>=19.1,<20.0':
  ERROR: Collecting private-package-published-on-privaterepo<0.5.0,>=0.4.0
    ERROR: Could not find a version that satisfies the requirement private-package-published-on-privaterepo<0.5.0,>=0.4.0 (from versions: none)
  ERROR: No matching distribution found for private-package-published-on-privaterepo<0.5.0,>=0.4.0
  ----------------------------------------
ERROR: Command "/Users/nbigaouette/private-package-from-parent-dir.git/subprojectname/.venv/bin/python /Users/nbigaouette/private-package-from-parent-dir.git/subprojectname/.venv/lib/python3.7/site-packages/pip install --ignore-installed --no-user --prefix /private/var/folders/3z/mjcq38mx3610kl4gnt9zw3gw0000gn/T/pip-build-env-zsn9ntu0/normal --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'private-package-published-on-privaterepo>=0.4.0,<0.5.0' 'structlog>=19.1,<20.0'" failed with error code 1 in None

As shown above, poetry is trying to install both private-package-published-on-privaterepo and structlog by using pypi.org, which are dependencies of the main project private-package-from-parent-dir. Surprisingly, both of these packages are already installed:

> poetry run python -c 'import structlog; print(structlog.__version__)'
19.1.0
> poetry run python -c 'import private_package_published_on_privaterepo; print(private_package_published_on_privaterepo.__version__)'
0.1.0

I did try to "incrementally" install the dependencies, for example by manually poetry add the structlog and private-package-published-on-privaterepo packages (which should be indirect dependencies) as to let poetry simply install the package from the parent directory but whatever I do it will always want to install the parent package's dependencies. See the gist for both parent project's and subproject's pyproject.toml files.

Poetry should have simply installed the private-package-from-parent-dir package from the parent directory (since I've used private-package-from-parent-dir = {path = ".."}), pull private-package-published-on-privaterepo from my private repo and pull structlog from pypi.org.

Start by comparing the parent and subproject pyproject.toml files from the linked gist, then reproduce the failure with poetry install -vvv from the subproject. Trace how the parent path dependency and its private repository dependency are resolved; done means installation uses the configured private source for the private package and PyPI for public dependencies.