empty string mapping key preservation

Would convert to explicit key (? '')

2 files changed, 6 insertions, 1 deletions

diff --git a/README.rst b/README.rst
index 4bbe9c0..58403df 100644
--- a/README.rst
+++ b/README.rst
@@ -54,6 +54,10 @@ ChangeLog
 
 .. should insert NEXT: at the beginning of line for next key (with empty line)
 
+NEXT:
+  - fix empty string mapping key roundtripping with preservation of quotes as `? ''`
+    (reported via email by Tomer Aharoni).
+
 0.16.5 (2019-08-18):
   - allow for ``YAML(typ=['unsafe', 'pytypes'])``
 
diff --git a/emitter.py b/emitter.py
index 73fbe05..41dc3e8 100644
--- a/emitter.py
+++ b/emitter.py
@@ -769,7 +769,8 @@ class Emitter(object):
             or (isinstance(self.event, MappingStartEvent) and self.event.flow_style is True)
             or (
                 isinstance(self.event, ScalarEvent)
-                and not self.analysis.empty
+                # if there is an explicit style for an empty string, it is a simple key
+                and not (self.analysis.empty and self.style and self.style not in '\'"')
                 and not self.analysis.multiline
             )
             or self.check_empty_sequence()