Don't import modules into packages

Importing modules in package's __init__.py has the unintended effect of
indirectly importing everything the module imports too. This has a few
problems:

* Impacts performance, as many, probably unused, dependencies need to be
  imported
* Makes it impossible to use optional dependencies, as all dependencies
  will be imported anyway

Also not importing modules makes it easier to understand what is a
module and what is a symbol/object living in the package.

Because of this change, now `default` needs to be explicitly imported
in `noxfile.py`.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

cookiecutter/{{cookiecutter.github_repo_name}}/noxfile.py

@@ -4,5 +4,6 @@
 """Configuration file for nox."""
 
 from frequenz.repo.config import nox
+from frequenz.repo.config.nox import default
 
-nox.configure(nox.default.{{cookiecutter.type}}_config)
+nox.configure(default.{{cookiecutter.type}}_config)

noxfile.py

@@ -4,12 +4,13 @@
 """Configuration file for nox."""
 
 from frequenz.repo.config import nox
+from frequenz.repo.config.nox import default
 
-config = nox.default.lib_config.copy()
+config = default.lib_config.copy()
 config.extra_paths.extend(
     [
         "cookiecutter/hooks",
         "cookiecutter/local_extensions.py",
     ]
 )
-nox.configure(nox.default.lib_config)
+nox.configure(default.lib_config)

src/frequenz/repo/config/__init__.py

@@ -31,8 +31,9 @@
 
 ```python
 from frequenz.repo.config import nox
+from frequenz.repo.config.nox import default
 
-nox.configure(nox.default.lib_config)
+nox.configure(default.lib_config)
 ```
 
 Again, make sure to pick the correct default configuration based on the type of your
@@ -44,8 +45,9 @@
 
 ```python
 from frequenz.repo.config import nox
+from frequenz.repo.config.nox import default
 
-config = nox.default.lib_config.copy()
+config = default.lib_config.copy()
 config.opts.black.append("--diff")
 nox.configure(config)
 ```
@@ -330,12 +332,8 @@
 defaults.
 """
 
-from . import mkdocs, nox, setuptools
 from ._core import RepositoryType
 
 __all__ = [
     "RepositoryType",
-    "mkdocs",
-    "nox",
-    "setuptools",
 ]

src/frequenz/repo/config/nox/__init__.py

@@ -10,21 +10,23 @@
 in the [`default`][] module. For example:
 
 ```python
-from frequenz.repo import config
+from frequenz.repo.config import nox
+from frequenz.repo.config.nox import default
 
-config.nox.configure(config.nox.default.lib_config)
+nox.configure(default.lib_config)
 ```
 
 If you need to modify the configuration, you can copy one of the default
 configurations by using the
 [`copy()`][frequenz.repo.config.nox.config.Config.copy] method:
 
 ```python
-from frequenz.repo import config
+from frequenz.repo.config import nox
+from frequenz.repo.config.nox import default
 
-conf = config.nox.default.lib_config.copy()
+conf = default.lib_config.copy()
 conf.opts.black.append("--diff")
-config.nox.configure(conf)
+nox.configure(conf)
 ```
 
 If you need further customization or to define new sessions, you can use the
@@ -41,13 +43,8 @@
 - [`util`][]: General purpose utility functions.
 """
 
-from . import config, default, session, util
 from .config import configure
 
 __all__ = [
-    "config",
     "configure",
-    "default",
-    "session",
-    "util",
 ]

src/frequenz/repo/config/setuptools/__init__.py

@@ -2,9 +2,3 @@
 # Copyright © 2023 Frequenz Energy-as-a-Service GmbH
 
 """Setuptools utilities."""
-
-from . import grpc_tools
-
-__all__ = [
-    "grpc_tools",
-]