Add note about checking sys.path for determining publicity

PyCQA · Aug 10, 2020 · 2f6ab9e · 2f6ab9e
1 parent dde693f
commit 2f6ab9e
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diff --git a/docs/snippets/publicity.rst b/docs/snippets/publicity.rst
@@ -27,6 +27,12 @@ a class called ``_Foo`` is considered private. A method ``bar`` in ``_Foo`` is
 also considered private since its parent is a private class, even though its
 name does not begin with a single underscore.
 
+Note, a construct's parent is recursively checked upward until we reach a directory
+in ``sys.path`` to avoid considering the complete filepath of a module.
+For example, consider the module ``/_foo/bar/baz.py``.
+If ``PYTHONPATH`` is set to ``/``, then ``baz.py`` is *private*.
+If ``PYTHONPATH`` is set to ``/_foo/``, then ``baz.py`` is *public*.
+
 Modules are parsed to look if ``__all__`` is defined. If so, only those top
 level constructs are considered public. The parser looks for ``__all__``
 defined as a literal list or tuple. As the parser doesn't execute the module,