Add build dependencies to package

Relates-to: #2789

poetry/core/factory.py

@@ -6,11 +6,15 @@
 from typing import Optional
 
 from .json import validate_object
+from .packages import DirectoryDependency
+from .packages import FileDependency
+from .packages import dependency_from_pep_508
 from .packages.dependency import Dependency
 from .packages.project_package import ProjectPackage
 from .poetry import Poetry
 from .spdx import license_by_id
 from .utils._compat import Path
+from .utils.helpers import canonicalize_name
 from .utils.toml_file import TomlFile
 
 
@@ -23,6 +27,8 @@ def create_poetry(self, cwd=None):  # type: (Optional[Path]) -> Poetry
         poetry_file = self.locate(cwd)
 
         local_config = TomlFile(poetry_file.as_posix()).read()
+        build_system = local_config.get("build-system", {})
+
         if "tool" not in local_config or "poetry" not in local_config["tool"]:
             raise RuntimeError(
                 "[tool.poetry] section not found in {}".format(poetry_file.name)
@@ -93,6 +99,36 @@ def create_poetry(self, cwd=None):  # type: (Optional[Path]) -> Poetry
 
                 package.add_dependency(name, constraint, category="dev")
 
+        for requirement in build_system.get("requires", []):
+            dependency = None
+            try:
+                dependency = dependency_from_pep_508(requirement)
+            except ValueError:
+                # PEP 517 requires can be path if not PEP 508
+                path = Path(requirement)
+                try:
+                    if path.is_file():
+                        dependency = FileDependency(
+                            name=canonicalize_name(path.name), path=path
+                        )
+                    elif path.is_dir():
+                        dependency = DirectoryDependency(
+                            name=canonicalize_name(path.name), path=path
+                        )
+                except OSError:
+                    # compatibility Python < 3.8
+                    # https://docs.python.org/3/library/pathlib.html#methods
+                    pass
+
+            if dependency is None:
+                # skip since we could not determine requirement
+                continue
+
+            if dependency.name not in {"poetry", "poetry-core"}:
+                package.add_dependency(
+                    dependency.name, dependency.constraint, category="build"
+                )
+
         extras = local_config.get("extras", {})
         for extra_name, requirements in extras.items():
             package.extras[extra_name] = []

poetry/core/packages/package.py

@@ -77,6 +77,7 @@ def __init__(self, name, version, pretty_version=None):
 
         self.requires = []
         self.dev_requires = []
+        self.build_requires = []
         self.extras = {}
         self.requires_extras = []
 
@@ -164,7 +165,7 @@ def maintainer_email(self):  # type: () -> str
 
     @property
     def all_requires(self):
-        return self.requires + self.dev_requires
+        return self.requires + self.dev_requires + self.build_requires
 
     def _get_author(self):  # type: () -> dict
         if not self._authors:
@@ -404,6 +405,8 @@ def add_dependency(
 
         if category == "dev":
             self.dev_requires.append(dependency)
+        elif category == "build":
+            self.build_requires.append(dependency)
         else:
             self.requires.append(dependency)
 
@@ -447,6 +450,9 @@ def clone(self):  # type: () -> Package
         for dep in self.dev_requires:
             clone.dev_requires.append(dep)
 
+        for dep in self.build_requires:
+            clone.build_requires.append(dep)
+
         return clone
 
     def __hash__(self):

tests/fixtures/project_with_build_system_requires/pyproject.toml

@@ -0,0 +1,22 @@
+[build-system]
+requires = [
+  "poetry-core",
+  "Cython~=0.29.6",
+]
+build-backend = "poetry.core.masonry.api"
+
+[tool.poetry]
+name = "poetry-cython-example"
+version = "0.1.0"
+description = ""
+authors = []
+include = [{ path = "project/**/*.so", format = "wheel" }]
+
+[tool.poetry.build]
+generate-setup-file = false
+script = "build.py"
+
+[tool.poetry.dependencies]
+python = "^3.7"
+
+[tool.poetry.dev-dependencies]

tests/test_factory.py

@@ -199,3 +199,22 @@ def test_create_poetry_fails_on_invalid_configuration():
   - 'description' is a required property
 """
     assert expected == str(e.value)
+
+
+def test_create_poetry_with_build_system_requires():
+    poetry = Factory().create_poetry(
+        fixtures_dir / "project_with_build_system_requires"
+    )
+    package = poetry.package
+
+    assert package.name == "poetry-cython-example"
+    assert package.version.text == "0.1.0"
+
+    assert not package.dev_requires
+    assert not package.requires
+
+    assert len(package.build_requires) == 1
+
+    dependency = package.build_requires[0]
+    assert dependency.category == "build"
+    assert dependency.to_pep_508() == "cython (>=0.29.6,<0.30.0)"