add note to configuration.rst that inline comments are not supported

1 files changed, 21 insertions, 1 deletions

diff --git a/docs/source/user/configuration.rst b/docs/source/user/configuration.rst
index 108dd98..4c53877 100644
--- a/docs/source/user/configuration.rst
+++ b/docs/source/user/configuration.rst
@@ -141,7 +141,7 @@ In our case, if we wanted to, we could also do
         dist
     max-complexity = 10
 
-This would allow us to add comments for why we're excluding items, e.g.,
+This allows us to add comments for why we're excluding items, e.g.
 
 .. code-block:: ini
 
@@ -164,6 +164,26 @@ This would allow us to add comments for why we're excluding items, e.g.,
 
 .. note::
 
+    Following the recommended settings for `Python's ``configparser`` <https://docs.python.org/3/library/configparser.html#customizing-parser-behaviour>`__, |Flake8| does not support inline comments for any of the keys. So while this is fine:
+
+    .. code-block:: ini
+
+        [flake8]
+        per-file-ignores =
+            # imported but unused
+            __init__.py: F401
+
+    this is not:
+
+    .. code-block:: ini
+
+        [flake8]
+        per-file-ignores =
+            __init__.py: F401 # imported but unused
+
+
+.. note::
+
     If you're using Python 2, you will notice that we download the
     :mod:`configparser` backport from PyPI. That backport enables us to
     support this behaviour on all supported versions of Python.