AttributeError: can't set attribute on "poetry install"

I manually solved #4333. Now I’m running into a more puzzling issue

• 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
• Poetry version: 1.2.0a
• Link of a Gist with the contents of your pyproject.toml file:

[tool.poetry]
name = "my_project"
version = "0.1.0"
description = "Poetry plugin to setup automated release"
authors = ["Sunds team <[e-mail]>"]

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

Issue

I’m trying to install the above dummy toml.

poetry install  -vvv

It should be trivial to execute. However, this crash with:

   2  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/mixology/version_solver.py:394 in _choose_package_version
       392│             version = locked
       393│ 
     → 394│         version = self._provider.complete_package(version)
       395│ 
       396│         conflict = False

   1  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/puzzle/provider.py:702 in complete_package
       700│             clean_dependencies.append(dep)
       701│ 
     → 702│         package.requires = clean_dependencies
       703│ 
       704│         return package

  AttributeError

  can't set attribute

  at /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/packages/dependency_package.py:38 in __setattr__
       34│     def __setattr__(self, key: str, value: Any) -> None:
       35│         if key in {"_dependency", "_package"}:
       36│             return super().__setattr__(key, value)
       37│ 
    →  38│         setattr(self._package, key, value)
       39│ 
       40│     def __str__(self) -> str:
       41│         return str(self._package)
       42│ 

Full stacktrace. Click to expand!

Loading configuration file /Users/epot/Library/Application Support/pypoetry/config.toml
Using virtualenv: /Users/epot/Library/Caches/pypoetry/virtualenvs/my-project-e_gpocHn-py3.8
Updating dependencies
Resolving dependencies...
   1: fact: my-project is 0.1.0
   1: derived: my-project
   1: Version solving took 0.012 seconds.
   1: Tried 1 solutions.

  Stack trace:
  16  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/cleo/application.py:330 in run
       328│ 
       329│             try:
     → 330│                 exit_code = self._run(io)
       331│             except Exception as e:
       332│                 if not self._catch_exceptions:

  15  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/console/application.py:167 in _run
       165│         self._load_plugins(io)
       166│ 
     → 167│         return super()._run(io)
       168│ 
       169│     def _configure_io(self, io: IO) -> None:

  14  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/cleo/application.py:425 in _run
       423│                 io.set_input(ArgvInput(argv))
       424│ 
     → 425│         exit_code = self._run_command(command, io)
       426│         self._running_command = None
       427│ 

  13  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/cleo/application.py:467 in _run_command
       465│ 
       466│         if error is not None:
     → 467│             raise error
       468│ 
       469│         return event.exit_code

  12  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/cleo/application.py:451 in _run_command
       449│ 
       450│             if event.command_should_run():
     → 451│                 exit_code = command.run(io)
       452│             else:
       453│                 exit_code = ConsoleCommandEvent.RETURN_CODE_DISABLED

  11  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/cleo/commands/base_command.py:118 in run
       116│         io.input.validate()
       117│ 
     → 118│         status_code = self.execute(io)
       119│ 
       120│         if status_code is None:

  10  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/cleo/commands/command.py:85 in execute
        83│ 
        84│         try:
     →  85│             return self.handle()
        86│         except KeyboardInterrupt:
        87│             return 1

   9  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/console/commands/install.py:75 in handle
        73│         self._installer.verbose(self._io.is_verbose())
        74│ 
     →  75│         return_code = self._installer.run()
        76│ 
        77│         if return_code != 0:

   8  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/installation/installer.py:112 in run
       110│         local_repo = Repository()
       111│ 
     → 112│         return self._do_install(local_repo)
       113│ 
       114│     def dry_run(self, dry_run: bool = True) -> "Installer":

   7  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/installation/installer.py:252 in _do_install
       250│             )
       251│ 
     → 252│             ops = solver.solve(use_latest=self._whitelist)
       253│         else:
       254│             self._io.write_line("Installing dependencies from lock file")

   6  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/puzzle/solver.py:99 in solve
        97│         with self._provider.progress():
        98│             start = time.time()
     →  99│             packages, depths = self._solve(use_latest=use_latest)
       100│             end = time.time()
       101│ 

   5  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/puzzle/solver.py:270 in _solve
       268│ 
       269│         try:
     → 270│             result = resolve_version(
       271│                 self._package, self._provider, locked=locked, use_latest=use_latest
       272│             )

   4  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/mixology/__init__.py:24 in resolve_version
        22│     solver = VersionSolver(root, provider, locked=locked, use_latest=use_latest)
        23│ 
     →  24│     return solver.solve()
        25│ 

   3  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/mixology/version_solver.py:82 in solve
        80│             while next is not None:
        81│                 self._propagate(next)
     →  82│                 next = self._choose_package_version()
        83│ 
        84│             return self._result()

   2  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/mixology/version_solver.py:394 in _choose_package_version
       392│             version = locked
       393│ 
     → 394│         version = self._provider.complete_package(version)
       395│ 
       396│         conflict = False

   1  /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/puzzle/provider.py:702 in complete_package
       700│             clean_dependencies.append(dep)
       701│ 
     → 702│         package.requires = clean_dependencies
       703│ 
       704│         return package

  AttributeError

  can't set attribute

  at /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/poetry/packages/dependency_package.py:38 in __setattr__
       34│     def __setattr__(self, key: str, value: Any) -> None:
       35│         if key in {"_dependency", "_package"}:
       36│             return super().__setattr__(key, value)
       37│ 
    →  38│         setattr(self._package, key, value)
       39│ 
       40│     def __str__(self) -> str:
       41│         return str(self._package)
       42│ 

[tardis10]

Looks like 1.2.0a2 is out now and fixes this issue.

[onerandomusername]

Looks like 1.2.0a2 is out now and fixes this issue.

Weird, it still happens for me.