_PyUnicode_Writer() now also reuses Unicode singletons:

vstinner · vstinner · commit 2cb16aa3cb31 · 2013-03-06T19:28:37.000+01:00
empty string and latin1 single character
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
@@ -12924,7 +12924,7 @@ _PyUnicodeWriter_Finish(_PyUnicodeWriter *writer)
         writer->buffer = newbuffer;
     }
     assert(_PyUnicode_CheckConsistency(writer->buffer, 1));
-    return writer->buffer;
+    return unicode_result_ready(writer->buffer);
 }
 
 void

Original file line number	Diff line number	Diff line change
`@@ -12924,7 +12924,7 @@ _PyUnicodeWriter_Finish(_PyUnicodeWriter *writer)`
`12924`	`12924`	`writer->buffer = newbuffer;`
`12925`	`12925`	`}`
`12926`	`12926`	`assert(_PyUnicode_CheckConsistency(writer->buffer, 1));`
`12927`		`- return writer->buffer;`
	`12927`	`+ return unicode_result_ready(writer->buffer);`
`12928`	`12928`	`}`
`12929`	`12929`
`12930`	`12930`	`void`