Fix build with separated poetry/poetry-core build systems

default.nix

@@ -108,7 +108,11 @@ lib.makeScope pkgs.newScope (self: {
                   mkPoetryDep = self.callPackage ./mk-poetry-dep.nix {
                     inherit pkgs lib python poetryLib evalPep508;
                   };
+
+                  # Use poetry-core from the poetry build (pep517/518 build-system)
+                  poetry-core = if __isBootstrap then null else poetryPkg.passthru.python.pkgs.poetry-core;
                   poetry = if __isBootstrap then null else poetryPkg;
+
                   # The canonical name is setuptools-scm
                   setuptools-scm = super.setuptools_scm;
 

overrides.nix

@@ -594,6 +594,22 @@ self: super:
     }
   );
 
+  poetry-core = super.poetry-core.overridePythonAttrs(old: {
+    # "Vendor" dependencies (for build-system support)
+    postPatch = ''
+      echo "import sys" >> poetry/__init__.py
+      for path in ''${PYTHONPATH//:/ }; do echo $path; done | uniq | while read path; do
+        echo "sys.path.insert(0, \"$path\")" >> poetry/__init__.py
+      done
+    '';
+
+    # Propagating dependencies leads to issues downstream
+    # We've already patched poetry to prefer "vendored" dependencies
+    postFixup = ''
+      rm $out/nix-support/propagated-build-inputs
+    '';
+  });
+
   # disable the removal of pyproject.toml, required because of setuptools_scm
   portend = super.portend.overridePythonAttrs (
     old: {

pkgs/poetry/default.nix

@@ -21,6 +21,11 @@ poetry2nix.mkPoetryApplication {
   '';
 
   postInstall = ''
+    # Figure out the location of poetry.core
+    # As poetry.core is using the same root import name as the poetry package and the python module system wont look for the root
+    # in the separate second location we need to link poetry.core to poetry
+    ln -s $(python -c 'import poetry.core; import os.path; print(os.path.dirname(poetry.core.__file__))') $out/${python.sitePackages}/poetry/core
+
     mkdir -p "$out/share/bash-completion/completions"
     "$out/bin/poetry" completions bash > "$out/share/bash-completion/completions/poetry"
     mkdir -p "$out/share/zsh/vendor-completions"