Removed adding a space into empty docstrings.

CHANGES.md

@@ -4,6 +4,7 @@
 
 ### _Black_
 
+- A space is no longer inserted into empty docstrings (#2249)
 - Respect `.gitignore` files in all levels, not only `root/.gitignore` file (apply
   `.gitignore` rules like `git` does) (#2225)
 - Restored compatibility with Click 8.0 on Python 3.6 when LANG=C used (#2227)

src/black/linegen.py

@@ -236,6 +236,7 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
             # characters but only if they are the same as the first.
             quote_len = 1 if docstring[1] != quote_char else 3
             docstring = docstring[quote_len:-quote_len]
+            docstring_started_empty = not docstring
 
             if is_multiline_string(leaf):
                 indent = " " * 4 * self.current_line.depth
@@ -255,8 +256,7 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
                         # Odd number of tailing backslashes, add some padding to
                         # avoid escaping the closing string quote.
                         docstring += " "
-            else:
-                # Add some padding if the docstring is empty.
+            elif not docstring_started_empty:
                 docstring = " "
 
             # We could enforce triple quotes at this point.

tests/data/docstring.py

@@ -102,7 +102,7 @@ def and_this():
   "hey yah"'''
 
 
-def empty():
+def multiline_whitespace():
     '''
 
 
@@ -111,11 +111,11 @@ def empty():
     '''
 
 
-def oneline_empty():
+def oneline_whitespace():
     '''      '''
 
 
-def oneline_nothing():
+def empty():
     """"""
 
 
@@ -293,16 +293,16 @@ def and_this():
     "hey yah"'''
 
 
-def empty():
+def multiline_whitespace():
     """ """
 
 
-def oneline_empty():
+def oneline_whitespace():
     """ """
 
 
-def oneline_nothing():
-    """ """
+def empty():
+    """"""
 
 
 def single_quotes():
@@ -374,4 +374,4 @@ def my_god_its_full_of_stars_1():
 
 # the space below is actually a \u2001, removed in output
 def my_god_its_full_of_stars_2():
-    "I'm sorry Dave"
+    "I'm sorry Dave"