Fixed installation.

Updated build and installation according to Poetry 1.0.1
See this for details:
python-poetry/poetry#2740

build.py

@@ -1,12 +1,14 @@
-# from distutils.command.build_ext import build_ext
-# from distutils.core import Extension
-from distutils.errors import CCompilerError, DistutilsExecError, DistutilsPlatformError
+import os
+import shutil
+
 from pybind11.setup_helpers import Pybind11Extension, build_ext
+from distutils.errors import CCompilerError, DistutilsExecError, DistutilsPlatformError
+from distutils.core import Distribution
 
 
 ext_modules = [
     Pybind11Extension(
-        "_combo", sources=["src/Graph.cpp", "src/Combo.cpp", "src/Binder.cpp"]
+        "pycombo._combo", sources=["src/Graph.cpp", "src/Combo.cpp", "src/Binder.cpp"]
     )
 ]
 
@@ -20,7 +22,7 @@ def run(self):
         try:
             build_ext.run(self)
         except (DistutilsPlatformError, FileNotFoundError):
-            raise BuildFailed("File not found. Could not compile C extension.")
+            raise BuildFailed("File not found. Could not compile C++ extension.")
 
     def build_extension(self, ext):
         try:
@@ -31,13 +33,32 @@ def build_extension(self, ext):
             DistutilsPlatformError,
             ValueError,
         ) as e:
-            raise BuildFailed(f"Could not compile C extension: {e}")
+            raise BuildFailed(f"Could not compile C++ extension: {e}")
 
 
 def build(setup_kwargs):
     """
     This function is mandatory in order to build the extensions.
     """
-    setup_kwargs.update(
-        {"ext_modules": ext_modules, "cmdclass": {"build_ext": ExtBuilder}}
-    )
+    distribution = Distribution({"name": "pycombo", "ext_modules": ext_modules})
+
+    cmd = ExtBuilder(distribution)
+    cmd.ensure_finalized()
+    cmd.run()
+
+    # Copy built extensions back to the project
+    for output in cmd.get_outputs():
+        relative_extension = os.path.relpath(output, cmd.build_lib)
+        if not os.path.exists(output):
+            continue
+
+        shutil.copyfile(output, relative_extension)
+        mode = os.stat(relative_extension).st_mode
+        mode |= (mode & 0o444) >> 2
+        os.chmod(relative_extension, mode)
+
+    return setup_kwargs
+
+
+if __name__ == "__main__":
+    build({})

pycombo/pyCombo.py

@@ -4,7 +4,7 @@
 
 import logging
 from typing import Optional, Tuple
-import _combo as comboCPP
+import pycombo._combo as comboCPP
 
 __author__ = "Philipp Kats"
 __copyright__ = "Philipp Kats"
@@ -27,7 +27,7 @@ def _check_repr(graph):
 def get_combo_partition(
     graph,
     weight_prop: Optional[str] = 'weight',
-    max_communities: int = -1,
+     max_communities: int = -1,
     modularity_resolution: int = 1,
     num_split_attempts: int = 0,
     fixed_split_step: int = 0,

pyproject.toml

@@ -4,7 +4,18 @@ version = "0.0.2"
 description = "Python wrapper around Combo network partitioning algorythm (C++)"
 authors = ["Philipp <casyfill@gmail.com>"]
 license = "MIT"
-build = 'build.py'
+
+include = [
+    # C++ sources must be included in the sdist distributions
+    {path = "src", format = "sdist"},
+    # C++ extension must be included in the wheel distributions
+    {path = "pycombo/*.so", format = "wheel"},
+    {path = "pycombo/*.pyd", format = "wheel"},
+]
+
+[tool.poetry.build]
+script = "build.py"
+generate-setup-file = false
 
 [tool.poetry.dependencies]
 python = "^3.7"
@@ -22,10 +33,8 @@ black = "^20.8b1"
 pre-commit = "^2.9.3"
 
 [build-system]
-requires = ["poetry>=0.12", "wheel", "setuptools","pybind11==2.6.0"]
-build-backend = "poetry.masonry.api"
-# requires = ["setuptools", "wheel", "pybind11==2.6.0"]
-# build-backend = "setuptools.build_meta"
+requires = ["poetry-core>=1.0.1", "pybind11==2.6.0"]
+build-backend = "poetry.core.masonry.api"
 
 [tool.pytest]
 testpaths = "tests"