[2.7] bpo-30754: Document textwrap.dedent blank line behavior. (GH-14469) (GH-14475)

* Added documentation for textwrap.dedent behavior.
(cherry picked from commit eb97b9211e7c99841d6cae8c63893b3525d5a401)

Co-authored-by: tmblweed <tmblweed@users.noreply.github.com>
https://bugs.python.org/issue30754

diff --git a/Doc/library/textwrap.rst b/Doc/library/textwrap.rst
index a50600e464dce1662be3db70316fe77880a664bf..6b0decb5a67f80d8c1221f48a593e9fc3e493665 100644 (file)
--- a/Doc/library/textwrap.rst
+++ b/Doc/library/textwrap.rst
@@ -66,6 +66,9 @@ indentation from strings that have unwanted whitespace to the left of the text.
    of this module incorrectly expanded tabs before searching for common leading
    whitespace.)
 
+   Lines containing only whitespace are ignored in the input and normalized to a
+   single newline character in the output.
+
    For example::
 
       def test():

diff --git a/Lib/textwrap.py b/Lib/textwrap.py
index 5c2e4fa5237c9def8c249f8de4d7e5b5e85d9ea5..8d91ffa081767335329cedf90bfc79b3a0022d3d 100644 (file)
--- a/Lib/textwrap.py
+++ b/Lib/textwrap.py
@@ -383,6 +383,8 @@ def dedent(text):
     considered to have no common leading whitespace.  (This behaviour is
     new in Python 2.5; older versions of this module incorrectly
     expanded tabs before searching for common leading whitespace.)
+
+    Entirely blank lines are normalized to a newline character.
     """
     # Look for the longest leading string of spaces and tabs common to
     # all lines.