non-package-mode:

- metadata like `name` and `version` is not required
- the root package is never installed (same as `--no-root`)
- building and publishing is not possible

src/poetry/console/commands/build.py

@@ -23,6 +23,10 @@ class BuildCommand(EnvCommand):
     def handle(self) -> int:
         from poetry.core.masonry.builder import Builder
 
+        if not self.poetry.is_package_mode:
+            self.line_error("Building a package is not possible in non-package mode.")
+            return 1
+
         with build_environment(poetry=self.poetry, env=self.env, io=self.io) as env:
             fmt = self.option("format") or "all"
             package = self.poetry.package

src/poetry/console/commands/install.py

@@ -152,7 +152,7 @@ def handle(self) -> int:
         if return_code != 0:
             return return_code
 
-        if self.option("no-root"):
+        if self.option("no-root") or not self.poetry.is_package_mode:
             return 0
 
         log_install = (
@@ -186,7 +186,10 @@ def handle(self) -> int:
             self.line_error(
                 f"The current project could not be installed: <error>{e}</error>\n"
                 "If you do not want to install the current project"
-                " use <c1>--no-root</c1>",
+                " use <c1>--no-root</c1>.\n"
+                "If you want to use Poetry only for dependency management"
+                " and not for packaging, you may also try the non-package mode.\n"
+                "In a future version of Poetry this warning will become an error!",
                 style="warning",
             )
             return 0

src/poetry/console/commands/publish.py

@@ -49,6 +49,10 @@ class PublishCommand(Command):
     def handle(self) -> int:
         from poetry.publishing.publisher import Publisher
 
+        if not self.poetry.is_package_mode:
+            self.line_error("Publishing a package is not possible in non-package mode.")
+            return 1
+
         publisher = Publisher(self.poetry, self.io)
 
         # Building package first, if told

src/poetry/factory.py

@@ -370,9 +370,9 @@ def validate(
 
         dependencies = {canonicalize_name(d) for d in dependencies}
 
-        if canonicalize_name(config["name"]) in dependencies:
+        if (name := config.get("name")) and canonicalize_name(name) in dependencies:
             results["errors"].append(
-                f"Project name ({config['name']}) is same as one of its dependencies"
+                f"Project name ({name}) is same as one of its dependencies"
             )
 
         return results

tests/console/commands/test_build.py

@@ -16,6 +16,22 @@
     from tests.types import FixtureDirGetter
 
 
+def test_build_not_possible_in_non_package_mode(
+    fixture_dir: FixtureDirGetter,
+    command_tester_factory: CommandTesterFactory,
+) -> None:
+    source_dir = fixture_dir("non_package_mode")
+
+    poetry = Factory().create_poetry(source_dir)
+    tester = command_tester_factory("build", poetry)
+
+    assert tester.execute() == 1
+    assert (
+        tester.io.fetch_error()
+        == "Building a package is not possible in non-package mode.\n"
+    )
+
+
 def test_build_with_multiple_readme_files(
     fixture_dir: FixtureDirGetter,
     tmp_path: Path,

tests/console/commands/test_check.py

@@ -5,6 +5,7 @@
 import pytest
 
 from poetry.packages import Locker
+from poetry.toml import TOMLFile
 
 
 if TYPE_CHECKING:
@@ -67,8 +68,6 @@ def test_check_valid(tester: CommandTester) -> None:
 def test_check_invalid(
     mocker: MockerFixture, tester: CommandTester, fixture_dir: FixtureDirGetter
 ) -> None:
-    from poetry.toml import TOMLFile
-
     mocker.patch(
         "poetry.poetry.Poetry.file",
         return_value=TOMLFile(fixture_dir("invalid_pyproject") / "pyproject.toml"),
@@ -108,8 +107,27 @@ def test_check_private(
     mocker: MockerFixture, tester: CommandTester, fixture_dir: FixtureDirGetter
 ) -> None:
     mocker.patch(
-        "poetry.factory.Factory.locate",
-        return_value=fixture_dir("private_pyproject") / "pyproject.toml",
+        "poetry.poetry.Poetry.file",
+        return_value=TOMLFile(fixture_dir("private_pyproject") / "pyproject.toml"),
+        new_callable=mocker.PropertyMock,
+    )
+
+    tester.execute()
+
+    expected = """\
+All set!
+"""
+
+    assert tester.io.fetch_output() == expected
+
+
+def test_check_non_package_mode(
+    mocker: MockerFixture, tester: CommandTester, fixture_dir: FixtureDirGetter
+) -> None:
+    mocker.patch(
+        "poetry.poetry.Poetry.file",
+        return_value=TOMLFile(fixture_dir("non_package_mode") / "pyproject.toml"),
+        new_callable=mocker.PropertyMock,
     )
 
     tester.execute()
@@ -136,8 +154,6 @@ def test_check_lock_missing(
     expected: str,
     expected_status: int,
 ) -> None:
-    from poetry.toml import TOMLFile
-
     mocker.patch(
         "poetry.poetry.Poetry.file",
         return_value=TOMLFile(fixture_dir("private_pyproject") / "pyproject.toml"),

tests/console/commands/test_install.py

@@ -416,7 +416,7 @@ def test_install_logs_output_decorated(
     assert tester.io.fetch_output() == expected
 
 
-@pytest.mark.parametrize("with_root", [True])
+@pytest.mark.parametrize("with_root", [True, False])
 @pytest.mark.parametrize("error", ["module", "readme", ""])
 def test_install_warning_corrupt_root(
     command_tester_factory: CommandTesterFactory,
@@ -488,3 +488,20 @@ def test_install_missing_directory_dependency_with_no_directory(
     else:
         with pytest.raises(ValueError, match="does not exist"):
             tester.execute(options)
+
+
+def test_non_package_mode_does_not_try_to_install_root(
+    command_tester_factory: CommandTesterFactory,
+    project_factory: ProjectFactory,
+) -> None:
+    content = """\
+[tool.poetry]
+mode = "non-package"
+"""
+    poetry = project_factory(name="non-package-mode", pyproject_content=content)
+
+    tester = command_tester_factory("install", poetry=poetry)
+    tester.execute()
+
+    assert tester.status_code == 0
+    assert tester.io.fetch_error() == ""

tests/console/commands/test_publish.py

@@ -7,6 +7,7 @@
 import pytest
 import requests
 
+from poetry.factory import Factory
 from poetry.publishing.uploader import UploadError
 
 
@@ -17,6 +18,24 @@
     from pytest_mock import MockerFixture
 
     from tests.helpers import PoetryTestApplication
+    from tests.types import CommandTesterFactory
+    from tests.types import FixtureDirGetter
+
+
+def test_publish_not_possible_in_non_package_mode(
+    fixture_dir: FixtureDirGetter,
+    command_tester_factory: CommandTesterFactory,
+) -> None:
+    source_dir = fixture_dir("non_package_mode")
+
+    poetry = Factory().create_poetry(source_dir)
+    tester = command_tester_factory("publish", poetry)
+
+    assert tester.execute() == 1
+    assert (
+        tester.io.fetch_error()
+        == "Publishing a package is not possible in non-package mode.\n"
+    )
 
 
 def test_publish_returns_non_zero_code_for_upload_errors(

tests/fixtures/non_package_mode/pyproject.toml

@@ -0,0 +1,7 @@
+[tool.poetry]
+mode = "non-package"
+
+[tool.poetry.dependencies]
+python = "^3.8"
+cleo = "^0.6"
+pendulum = { git = "https://github.com/sdispater/pendulum.git", branch = "2.0" }

tests/test_factory.py

@@ -224,6 +224,12 @@ def test_create_poetry_with_multi_constraints_dependency(
     assert len(package.requires) == 2
 
 
+def test_create_poetry_non_package_mode(fixture_dir: FixtureDirGetter) -> None:
+    poetry = Factory().create_poetry(fixture_dir("non_package_mode"))
+
+    assert not poetry.is_package_mode
+
+
 def test_poetry_with_default_source_legacy(
     fixture_dir: FixtureDirGetter, with_simple_keyring: None
 ) -> None: