commit b7e2d67f7c035f09c921ca4e7a36529cd502ccf7
author Serhiy Storchaka <storchaka@gmail.com> Tue Feb 13 08:27:33 2018 +0200
committer GitHub <noreply@github.com> Tue Feb 13 08:27:33 2018 +0200
tree 4587c06804f87baacc8edf3be772b0046f4d1ea0
parent 688722cedd6437910ff185ecf94fb3b749ad37f2

bpo-32827: Fix usage of _PyUnicodeWriter_Prepare() in decoding errors handler. (GH-5636)

Objects/unicodeobject.c

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index f5e4ab6..0233438 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -4256,7 +4256,7 @@
     }
     if (need_to_grow) {
         writer->overallocate = 1;
-        if (_PyUnicodeWriter_Prepare(writer, writer->min_length,
+        if (_PyUnicodeWriter_Prepare(writer, writer->min_length - writer->pos,
                             PyUnicode_MAX_CHAR_VALUE(repunicode)) == -1)
             goto onError;
     }
@@ -6085,9 +6085,7 @@
                 &writer)) {
             goto onError;
         }
-        if (_PyUnicodeWriter_Prepare(&writer, writer.min_length, 127) < 0) {
-            goto onError;
-        }
+        assert(end - s <= writer.size - writer.pos);
 
 #undef WRITE_ASCII_CHAR
 #undef WRITE_CHAR
@@ -6364,9 +6362,7 @@
                 &writer)) {
             goto onError;
         }
-        if (_PyUnicodeWriter_Prepare(&writer, writer.min_length, 127) < 0) {
-            goto onError;
-        }
+        assert(end - s <= writer.size - writer.pos);
 
 #undef WRITE_CHAR
     }