feat: check requires-poetry before any validation

src/poetry/factory.py

@@ -23,6 +23,7 @@
 from poetry.plugins.plugin import Plugin
 from poetry.plugins.plugin_manager import PluginManager
 from poetry.poetry import Poetry
+from poetry.pyproject.toml import PyProjectTOML
 from poetry.toml.file import TOMLFile
 
 
@@ -46,6 +47,20 @@ class Factory(BaseFactory):
     Factory class to create various elements needed by Poetry.
     """
 
+    def _ensure_valid_poetry_version(self, cwd: Path | None) -> None:
+        poetry_file = self.locate(cwd)
+        pyproject = PyProjectTOML(path=poetry_file)
+        poetry_config = pyproject.data.get("tool", {}).get("poetry", {})
+
+        if version_str := poetry_config.get("requires-poetry"):
+            version_constraint = parse_constraint(version_str)
+            version = Version.parse(__version__)
+            if not version_constraint.allows(version):
+                raise PoetryError(
+                    f"This project requires Poetry {version_constraint},"
+                    f" but you are using Poetry {version}"
+                )
+
     def create_poetry(
         self,
         cwd: Path | None = None,
@@ -57,16 +72,9 @@ def create_poetry(
         if io is None:
             io = NullIO()
 
-        base_poetry = super().create_poetry(cwd=cwd, with_groups=with_groups)
+        self._ensure_valid_poetry_version(cwd)
 
-        if version_str := base_poetry.local_config.get("requires-poetry"):
-            version_constraint = parse_constraint(version_str)
-            version = Version.parse(__version__)
-            if not version_constraint.allows(version):
-                raise PoetryError(
-                    f"This project requires Poetry {version_constraint},"
-                    f" but you are using Poetry {version}"
-                )
+        base_poetry = super().create_poetry(cwd=cwd, with_groups=with_groups)
 
         poetry_file = base_poetry.pyproject_path
         locker = Locker(poetry_file.parent / "poetry.lock", base_poetry.pyproject.data)

tests/fixtures/self_version_not_ok_invalid_config/pyproject.toml

@@ -0,0 +1,7 @@
+[tool.poetry]
+package-mode = false
+requires-poetry = "<1.2"
+invalid_option = 42
+
+[tool.poetry.dependencies]
+python = "^3.8"

tests/test_factory.py

@@ -256,6 +256,17 @@ def test_create_poetry_version_not_ok(fixture_dir: FixtureDirGetter) -> None:
     )
 
 
+def test_create_poetry_check_version_before_validation(
+    fixture_dir: FixtureDirGetter,
+) -> None:
+    with pytest.raises(PoetryError) as e:
+        Factory().create_poetry(fixture_dir("self_version_not_ok_invalid_config"))
+    assert (
+        str(e.value)
+        == f"This project requires Poetry <1.2, but you are using Poetry {__version__}"
+    )
+
+
 @pytest.mark.parametrize(
     "project",
     ("with_primary_source_implicit", "with_primary_source_explicit"),