feat(cli): default new command to src layout

Resolves: #9390

Author: abn

docs/cli.md

@@ -589,8 +589,8 @@ poetry lock
 
 ## new
 
-This command will help you kickstart your new Python project by creating
-a directory structure suitable for most projects.
+This command will help you kickstart your new Python project by creating a new Poetry project. By default, a `src`
+layout is chosen.
 
 ```bash
 poetry new my-package
@@ -602,8 +602,9 @@ will create a folder as follows:
 my-package
 ├── pyproject.toml
 ├── README.md
-├── my_package
-│   └── __init__.py
+├── src
+│   └── my_package
+│       └── __init__.py
 └── tests
     └── __init__.py
 ```
@@ -615,10 +616,10 @@ the `--name` option:
 poetry new my-folder --name my-package
 ```
 
-If you want to use a src folder, you can use the `--src` option:
+If you want to use a `flat` project layout, you can use the `--flat` option:
 
 ```bash
-poetry new --src my-package
+poetry new --flat my-package
 ```
 
 That will create a folder structure as follows:
@@ -627,18 +628,22 @@ That will create a folder structure as follows:
 my-package
 ├── pyproject.toml
 ├── README.md
-├── src
-│   └── my_package
-│       └── __init__.py
+├── my_package
+│   └── __init__.py
 └── tests
     └── __init__.py
 ```
 
+{{% note %}}
+For an overview of the differences between `flat` and `src` layouts, please see
+[here](https://packaging.python.org/en/latest/discussions/src-layout-vs-flat-layout/).
+{{% /note %}}
+
 The `--name` option is smart enough to detect namespace packages and create
 the required structure for you.
 
 ```bash
-poetry new --src --name my.package my-package
+poetry new --name my.package my-package
 ```
 
 will create the following structure:
@@ -659,7 +664,7 @@ my-package
 
 * `--interactive (-i)`: Allow interactive specification of project configuration.
 * `--name`: Set the resulting package name.
-* `--src`: Use the src layout for the project.
+* `--flat`: Use the flat layout for the project.
 * `--readme`: Specify the readme file extension. Default is `md`. If you intend to publish to PyPI
   keep the [recommendations for a PyPI-friendly README](https://packaging.python.org/en/latest/guides/making-a-pypi-friendly-readme/)
   in mind.

src/poetry/console/commands/new.py

@@ -29,7 +29,13 @@ class NewCommand(InitCommand):
             flag=True,
         ),
         option("name", None, "Set the resulting package name.", flag=False),
-        option("src", None, "Use the src layout for the project."),
+        option(
+            "src",
+            None,
+            "Use the src layout for the project. "
+            "<warning>Deprecated</>: This is the default option now.",
+        ),
+        option("flat", None, "Use the flat layout for the project."),
         option(
             "readme",
             None,
@@ -72,9 +78,14 @@ def handle(self) -> int:
                 f"Destination <fg=yellow>{path}</> exists and is not empty"
             )
 
+        if self.option("src"):
+            self.line_error(
+                "The <c1>--src</> option is now the default and will be removed in a future version."
+            )
+
         return self._init_pyproject(
             project_path=path,
             allow_interactive=self.option("interactive"),
-            layout_name="src" if self.option("src") else "standard",
+            layout_name="standard" if self.option("flat") else "src",
             readme_format=self.option("readme") or "md",
         )

tests/console/commands/conftest.py

@@ -34,3 +34,24 @@ def init_basic_toml() -> str:
 readme = "README.md"
 requires-python = ">=3.6"
 """
+
+
+@pytest.fixture()
+def new_basic_toml() -> str:
+    return """\
+[project]
+name = "my-package"
+version = "1.2.3"
+description = "This is a description"
+authors = [
+    {name = "Your Name",email = "[email protected]"}
+]
+license = {text = "MIT"}
+readme = "README.md"
+requires-python = ">=3.6"
+dependencies = [
+]
+
+[tool.poetry]
+packages = [{include = "my_package", from = "src"}]
+"""

tests/console/commands/test_new.py

@@ -32,7 +32,7 @@ def verify_project_directory(
     path: Path,
     package_name: str,
     package_path: str | Path,
-    include_from: str | None = None,
+    is_flat: bool = False,
 ) -> Poetry:
     package_path = Path(package_path)
     assert path.is_dir()
@@ -49,13 +49,13 @@ def verify_project_directory(
     poetry = Factory().create_poetry(cwd=path)
     assert poetry.package.name == package_name
 
-    if include_from:
+    if is_flat:
+        package_include = {"include": package_path.parts[0]}
+    else:
         package_include = {
-            "include": package_path.relative_to(include_from).parts[0],
-            "from": include_from,
+            "include": package_path.relative_to("src").parts[0],
+            "from": "src",
         }
-    else:
-        package_include = {"include": package_path.parts[0]}
 
     name = poetry.package.name
     packages = poetry.local_config.get("packages")
@@ -72,81 +72,87 @@ def verify_project_directory(
 @pytest.mark.parametrize(
     "options,directory,package_name,package_path,include_from",
     [
-        ([], "package", "package", "package", None),
-        (["--src"], "package", "package", "src/package", "src"),
+        (["--flat"], "package", "package", "package", None),
+        ([], "package", "package", "src/package", "src"),
         (
-            ["--name namespace.package"],
+            ["--flat", "--name namespace.package"],
             "namespace-package",
             "namespace-package",
             "namespace/package",
             None,
         ),
         (
-            ["--src", "--name namespace.package"],
+            ["--name namespace.package"],
             "namespace-package",
             "namespace-package",
             "src/namespace/package",
             "src",
         ),
         (
-            ["--name namespace.package_a"],
+            ["--flat", "--name namespace.package_a"],
             "namespace-package_a",
             "namespace-package-a",
             "namespace/package_a",
             None,
         ),
         (
-            ["--src", "--name namespace.package_a"],
+            ["--name namespace.package_a"],
             "namespace-package_a",
             "namespace-package-a",
             "src/namespace/package_a",
             "src",
         ),
         (
-            ["--name namespace_package"],
+            ["--flat", "--name namespace_package"],
             "namespace-package",
             "namespace-package",
             "namespace_package",
             None,
         ),
         (
-            ["--name namespace_package", "--src"],
+            ["--name namespace_package"],
             "namespace-package",
             "namespace-package",
             "src/namespace_package",
             "src",
         ),
         (
-            ["--name namespace.package"],
+            ["--flat", "--name namespace.package"],
             "package",
             "namespace-package",
             "namespace/package",
             None,
         ),
         (
-            ["--name namespace.package", "--src"],
+            ["--name namespace.package"],
             "package",
             "namespace-package",
             "src/namespace/package",
             "src",
         ),
         (
-            ["--name namespace.package"],
+            ["--name namespace.package", "--flat"],
             "package",
             "namespace-package",
             "namespace/package",
             None,
         ),
         (
-            ["--name namespace.package", "--src"],
+            ["--name namespace.package"],
             "package",
             "namespace-package",
             "src/namespace/package",
             "src",
         ),
-        ([], "namespace_package", "namespace-package", "namespace_package", None),
         (
-            ["--src", "--name namespace_package"],
+            ["--flat"],
+            "namespace_package",
+            "namespace-package",
+            "namespace_package",
+            None,
+        ),
+        (
+            ["--name namespace_package"],
             "namespace_package",
             "namespace-package",
             "src/namespace_package",
@@ -166,7 +172,7 @@ def test_command_new(
     path = tmp_path / directory
     options.append(str(path))
     tester.execute(" ".join(options))
-    verify_project_directory(path, package_name, package_path, include_from)
+    verify_project_directory(path, package_name, package_path, "--flat" in options)
 
 
 @pytest.mark.parametrize(("fmt",), [(None,), ("md",), ("rst",), ("adoc",), ("creole",)])
@@ -182,7 +188,7 @@ def test_command_new_with_readme(
 
     tester.execute(" ".join(options))
 
-    poetry = verify_project_directory(path, package, package, None)
+    poetry = verify_project_directory(path, package, Path("src") / package)
     project_section = poetry.pyproject.data["project"]
     assert isinstance(project_section, dict)
     assert project_section["readme"] == f"README.{fmt or 'md'}"
@@ -237,9 +243,9 @@ def mock_check_output(cmd: str, *_: Any, **__: Any) -> str:
 
 
 def test_basic_interactive_new(
-    tester: CommandTester, tmp_path: Path, init_basic_inputs: str, init_basic_toml: str
+    tester: CommandTester, tmp_path: Path, init_basic_inputs: str, new_basic_toml: str
 ) -> None:
     path = tmp_path / "somepackage"
     tester.execute(f"--interactive {path.as_posix()}", inputs=init_basic_inputs)
-    verify_project_directory(path, "my-package", "my_package", None)
-    assert init_basic_toml in tester.io.fetch_output()
+    verify_project_directory(path, "my-package", "src/my_package")
+    assert new_basic_toml in tester.io.fetch_output()