1.0.10 -> 1.1 regression: EnvCommandError: 'No module named setuptools' on Python 3.7

This may because it’s installing a nested package. Python 3.8 doesn’t have this issue but 3.7 does. I don’t have a reduced test case yet. I’m hoping the traceback is helpful and someone knows what’s going on from it. Python 3.7 and 3.8 are fine with Poetry 1.0.10, everything else being identical. Python 3.8 with Poetry 1.1.2 is fine as well, just not Python 3.7 with Poetry 1.1.2.

 EnvCommandError
  Command ['/usr/local/bin/python', '-m', 'pip', 'install', '--no-deps', '-U', '/builds/[redacted]'] errored with the following return code 2, and output: 
  Looking in indexes: https://[redacted]
  Processing ./packages/[redacted]
    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'
  ERROR: Exception:
  Traceback (most recent call last):
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/cli/base_command.py", line 216, in _main
      status = self.run(options, args)
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/cli/req_command.py", line 182, in wrapper
      return func(self, options, args)
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/commands/install.py", line 325, in run
      reqs, check_supported_wheels=not options.target_dir
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/resolution/legacy/resolver.py", line 183, in resolve
      discovered_reqs.extend(self._resolve_one(requirement_set, req))
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/resolution/legacy/resolver.py", line 388, in _resolve_one
      abstract_dist = self._get_abstract_dist_for(req_to_install)
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/resolution/legacy/resolver.py", line 340, in _get_abstract_dist_for
      abstract_dist = self.preparer.prepare_linked_requirement(req)
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/operations/prepare.py", line 483, in prepare_linked_requirement
      req, self.req_tracker, self.finder, self.build_isolation,
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/operations/prepare.py", line 91, in _get_prepared_distribution
      abstract_dist.prepare_distribution_metadata(finder, build_isolation)
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/distributions/sdist.py", line 38, in prepare_distribution_metadata
      self._setup_isolation(finder)
    File "/usr/local/lib/python3.7/site-packages/pip/_internal/distributions/sdist.py", line 96, in _setup_isolation
      reqs = backend.get_requires_for_build_wheel()
    File "/usr/local/lib/python3.7/site-packages/pip/_vendor/pep517/wrappers.py", line 161, in get_requires_for_build_wheel
      'config_settings': config_settings
    File "/usr/local/lib/python3.7/site-packages/pip/_vendor/pep517/wrappers.py", line 265, in _call_hook
      raise BackendUnavailable(data.get('traceback', ''))
  pip._vendor.pep517.wrappers.BackendUnavailable: Traceback (most recent call last):
    File "/usr/local/lib/python3.7/site-packages/pip/_vendor/pep517/_in_process.py", line 86, in _build_backend
      obj = import_module(mod_path)
    File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
    File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
    File "<frozen importlib._bootstrap>", line 983, in _find_and_load
    File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
    File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/tmp/pip-build-env-l4t_85ci/overlay/lib/python3.7/site-packages/poetry/masonry/api.py", line 1, in <module>
      from poetry.core.masonry.api import build_sdist
    File "/tmp/pip-build-env-l4t_85ci/overlay/lib/python3.7/site-packages/poetry/core/masonry/__init__.py", line 10, in <module>
      from .builder import Builder
    File "/tmp/pip-build-env-l4t_85ci/overlay/lib/python3.7/site-packages/poetry/core/masonry/builder.py", line 6, in <module>
      from .builders.sdist import SdistBuilder
    File "/tmp/pip-build-env-l4t_85ci/overlay/lib/python3.7/site-packages/poetry/core/masonry/builders/__init__.py", line 2, in <module>
      from .wheel import WheelBuilder
    File "/tmp/pip-build-env-l4t_85ci/overlay/lib/python3.7/site-packages/poetry/core/masonry/builders/wheel.py", line 18, in <module>
      from packaging.tags import sys_tags
    File "/tmp/pip-build-env-l4t_85ci/overlay/lib/python3.7/site-packages/poetry/core/_vendor/packaging/tags.py", line 7, in <module>
      import distutils.util
    File "/usr/local/lib/python3.7/site-packages/_distutils_hack/__init__.py", line 83, in create_module
      return importlib.import_module('._distutils', 'setuptools')
    File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
  ModuleNotFoundError: No module named 'setuptools'

[kbakk]

In https://github.com/python-poetry/poetry/issues/1135#issuecomment-719902456 @NeilGirdhar pointed out that one would need to change pyproject.toml to include setuptools:

[build-system]
-requires = ["poetry_core>=1.0"]
+requires = ["setuptools", "poetry_core>=1.0"]
build-backend = "poetry.core.masonry.api"

With this added in my above example (reproduce-3153.zip) it now builds:

poetry run pip install -e .
Obtaining file:///Users/kristofferb/Code/temp/gist-reproduce-3153
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Installing collected packages: reproduce-issue
  Attempting uninstall: reproduce-issue
    Found existing installation: reproduce-issue 0.1.0
    Uninstalling reproduce-issue-0.1.0:
      Successfully uninstalled reproduce-issue-0.1.0
  Running setup.py develop for reproduce-issue
Successfully installed reproduce-issue

And indeed, as others have mentioned in https://github.com/python-poetry/poetry/issues/34, this is not a poetry issue. But it seems like many would like poetry to have a workaround.

[jtzero]

same issue, wrapt depends on it, manually removing setuptools from the poetry.lock worked for me

diff --git a/poetry.lock b/poetry.lock
index c8f8357..f858bfe 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -868,18 +868,6 @@ botocore = ">=1.12.36,<2.0a.0"
 [package.extras]
 crt = ["botocore[crt] (>=1.20.29,<2.0a.0)"]

-[[package]]
-name = "setuptools"
-version = "57.4.0"
-description = "Easily download, build, install, upgrade, and uninstall Python packages"
-category = "main"
-optional = false
-python-versions = ">=3.6"
-
-[package.extras]
-docs = ["sphinx", "jaraco.packaging (>=8.2)", "rst.linker (>=1.9)", "jaraco.tidelift (>=1.4)", "pygments-github-lexers (==0.0.5)", "sphinx-inline-tabs", "sphinxcontrib-towncrier", "furo"]
-testing = ["pytest (>=4.6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-cov", "pytest-enabler (>=1.0.1)", "mock", "flake8-2020", "virtualenv (>=13.0.0)", "pytest-virtualenv (>=1.2.7)", "wheel", "paver", "pip (>=19.1)", "jaraco.envs", "pytest-xdist", "sphinx", "jaraco.path (>=3.2.0)", "pytest-black (>=0.3.7)", "pytest-mypy"]
-
 [[package]]
 name = "six"
 version = "1.16.0"
@@ -1555,10 +1543,6 @@ s3transfer = [
     {file = "s3transfer-0.5.0-py3-none-any.whl", hash = "sha256:9c1dc369814391a6bda20ebbf4b70a0f34630592c9aa520856bf384916af2803"},
     {file = "s3transfer-0.5.0.tar.gz", hash = "sha256:50ed823e1dc5868ad40c8dc92072f757aa0e653a192845c94a3b676f4a62da4c"},
 ]
-setuptools = [
-    {file = "setuptools-57.4.0-py3-none-any.whl", hash = "sha256:a49230977aa6cfb9d933614d2f7b79036e9945c4cdd7583163f4e920b83418d6"},
-    {file = "setuptools-57.4.0.tar.gz", hash = "sha256:6bac238ffdf24e8806c61440e755192470352850f3419a52f26ffe0a1a64f465"},
-]
 six = [
     {file = "six-1.16.0-py2.py3-none-any.whl", hash = "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"},
     {file = "six-1.16.0.tar.gz", hash = "sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926"},

> rm -rf "$(poetry env info --path)"
> poetry install
...
Installing wrapt (1.12.1)