poetry update AttributeError: 'EmptyConstraint' object has no attribute 'allows'

[mdengler]

• 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).
  Gist of output is: https://gist.github.com/mdengler/7be12f9c481567c7872bc2ea712464b6

• OS version and name: Fedora 34

$ cat /etc/fedora-release 
Fedora release 34 (Thirty Four)

• Poetry version: Poetry version 1.1.6

$ poetry --version
Poetry version 1.1.6

• Link of a Gist with the contents of your pyproject.toml file: Unpublished software, so if there is a need for this file, I can provide privately.

Issue

I have received this error message:

$ poetry update 
Updating dependencies                                                                                                                                         
Resolving dependencies... (34.4s)                                                                                                                             
                                                                                                                                                              
Writing lock file                                                                                                                                             
                                                                                                                                                              
  AttributeError                                                                                                                                              
                                                                                                                                                              
  'EmptyConstraint' object has no attribute 'allows'                                                                                                          
                                                                                                                                                              
  at ~/.local/lib/python3.9/site-packages/poetry/core/version/markers.py:291 in validate                                                                      
      287│                                                                                                                                                    
      288│         if self._name not in environment:                                                                                                          
      289│             return True                                                                                                                            
      290│                                                                                                                                                    
    → 291│         return self._constraint.allows(self._parser(environment[self._name]))                                                                      
      292│                                                                                                                                                    
      293│     def without_extras(self):  # type: () -> MarkerTypes                                                                                           
      294│         return self.exclude("extra")                                                                                                               
      295│                                                  

I made this change as a workaround:

$ diff -uw ~/.local/lib/python3.9/site-packages/poetry/core/version/markers.py{~,}
--- /home/martin/.local/lib/python3.9/site-packages/poetry/core/version/markers.py~     2021-04-21 11:44:56.085692322 -0400
+++ /home/martin/.local/lib/python3.9/site-packages/poetry/core/version/markers.py      2021-08-19 11:38:17.934769254 -0400
@@ -288,6 +288,9 @@
         if self._name not in environment:
             return True
 
+        if not hasattr(self._constraint, "allows"):
+            return True
+
         return self._constraint.allows(self._parser(environment[self._name]))
 
     def without_extras(self):  # type: () -> MarkerTypes
$ diff -uw ~/.local/lib/python3.9/site-packages/poetry/core/version/markers.py{~,}
--- /home/martin/.local/lib/python3.9/site-packages/poetry/core/version/markers.py~     2021-04-21 11:44:56.085692322 -0400
+++ /home/martin/.local/lib/python3.9/site-packages/poetry/core/version/markers.py      2021-08-19 11:38:17.934769254 -0400
@@ -288,6 +288,9 @@
         if self._name not in environment:
             return True
 
+        if not hasattr(self._constraint, "allows"):
+            return True
+
         return self._constraint.allows(self._parser(environment[self._name]))
 
     def without_extras(self):  # type: () -> MarkerTypes

I gathered some extra debugging information that points to greenlet and sqlalchemy as being involved in the issue: https://gist.github.com/mdengler/7be12f9c481567c7872bc2ea712464b6

[elbakramer]

Upgrading poetry to 1.1.8 may solve the issue.
Check #4402 for for more information.

[mdengler]

Thanks -- looks like this is a dupe, then.

[mrtolkien]

I have the same issue with the current preview build, poetry 1.2.0a2

Will there be another preview build that fixes it?

[bipinkc19]

I have the same issue with the current preview build, poetry 1.2.0a2

Will there be another preview build that fixes it?

Been getting the same problem.

[alanorth]

I'm doing poetry update with poetry 1.1.8 on a project that indirectly includes sqlalchemy and I get this error too:

$ poetry update                                                                                                  
Updating dependencies                                                                                                                                          
Resolving dependencies... (1.3s)                                                                                                                               
                                                                                                                                                               
  AttributeError                                                                                                                                               
                                                                                                                                                               
  'EmptyConstraint' object has no attribute 'allows'                                                                                                           
                                                                                                                                                               
  at /usr/lib/python3.9/site-packages/poetry/core/version/markers.py:291 in validate                                                                           
      287│                                                                                                                                                     
      288│         if self._name not in environment:                                                                                                           
      289│             return True                                                                                                                             
      290│                                                                                                                                                     
    → 291│         return self._constraint.allows(self._parser(environment[self._name]))                                                                       
      292│                                                                                                                                                     
      293│     def without_extras(self):  # type: () -> MarkerTypes                                                                                            
      294│         return self.exclude("extra")                                                                                                                
      295│   

Link to pyproject.toml.

[tcaiazza]

I get the same error as others, 'EmptyConstraint' object has no attribute 'allows' and through some trail and error it looks like the issue is with sqlalchemy version 1.4.23. If I pin it to 1.4.22 everything works as expected.

Note: i'm using poetry 1.2.0a1

[mahenzon]

Yeah, happens with sqlalchemy

[[package]]
name = "sqlalchemy"
version = "1.4.23"
description = "Database Abstraction Library"
category = "main"
optional = false
python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*,>=2.7"

[package.dependencies]
greenlet = {version = "!=0.4.17", markers = "python_version >= \"3\" and platform_machine in \"x86_64 X86_64 aarch64 AARCH64 ppc64le PPC64LE amd64 AMD64 win32 WIN32\""}

platform_machine in "x86_64 X86_64 aarch64 AARCH64 ppc64le PPC64LE amd64 AMD64 win32 WIN32" seems to be unexpected for poetry

[alanorth]

@errsolve7 this is not solved with Poetry 1.1.8 or current master, as several commenters and I have noted.

[sodality-ramsey]

[Already Solved] AttributeError ‘EmptyConstraint’ object has no attribute ‘allows’

Please do not follow this link, this user is attempting a phishing scam. Comment is reported.

As an aside, updating to Poetry 1.1.8 fixed the AttributeError: 'EmptyConstraint' object has no attribute 'allows' error for me.

[mahenzon]

Yeah, fixed for me too in 1.1.8, was getting it with 1.1.7

[pengfei99]

Also fixed for me too in 1.1.8, was getting it with 1.1.6

[fulopkovacs]

I get the same error as others, 'EmptyConstraint' object has no attribute 'allows' and through some trail and error it looks like the issue is with sqlalchemy version 1.4.23. If I pin it to 1.4.22 everything works as expected.

Note: i'm using poetry 1.2.0a1

Pinning sqlalchemy to 1.4.22 solved this problem for me too (I'm using poetry 1.1.0). What's weird is that this problem does not occur in our CI where we use images based on python:3.6.x-slim and python:3.8.x. I have Python 3.9 installed on my computer (Manjaro Linux) and all the previous commenters whose logs I've seen so far are using Python 3.9 too. Maybe it's an issue with Python 3.9? Just a thought, though, I haven't actually tested it.

[github-actions]

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