Is __init__.py not required for packages in Python 3.3 ?

Python 3.3 and later versions introduce the concept of namespace packages. This feature allows you to create a package without an __init__.py file.

Namespace Packages vs. Regular Packages

• Namespace packages: Do not have an __init__.py file, allowing for multiple modules to contribute to the same package across different directories.
• Regular packages: Have an __init__.py file, making them self-contained and isolating their modules to a single directory hierarchy.

When to Use Namespace Packages

The primary use case for namespace packages is when you have multiple libraries residing in different locations and want them to contribute a subpackage to the parent package.

For example:

google_pubsub/ <- Package 1

google/                 <- Namespace package (no __init__.py)
    cloud/              <- Namespace package (no __init__.py)
        pubsub/         <- Regular package (with __init__.py)
            __init__.py <- Required to make the package a regular package
            foo.py

google_storage/ <- Package 2

google/                 <- Namespace package (no __init__.py)
    cloud/              <- Namespace package (no __init__.py)
        storage/        <- Regular package (with __init__.py)
            __init__.py <- Required to make the package a regular package
            bar.py

In this example, both google_pubsub and google_storage share the same google/cloud namespace. This allows you to import modules from either library without providing the full path.

Regular Packages

For most use cases, creating regular packages with __init__.py files is still the recommended approach. This provides self-containment and prevents potential namespace conflicts.

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