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

serhiy-storchaka · web-flow · commit b7e2d67f7c03 · 2018-02-13T08:27:33.000+02:00
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
@@ -4256,7 +4256,7 @@ unicode_decode_call_errorhandler_writer(
     }
     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 @@ _PyUnicode_DecodeUnicodeEscape(const char *s,
                 &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 @@ PyUnicode_DecodeRawUnicodeEscape(const char *s,
                 &writer)) {
             goto onError;
         }
-        if (_PyUnicodeWriter_Prepare(&writer, writer.min_length, 127) < 0) {
-            goto onError;
-        }
+        assert(end - s <= writer.size - writer.pos);
 
 #undef WRITE_CHAR
     }

Original file line number	Diff line number	Diff line change
`@@ -4256,7 +4256,7 @@ unicode_decode_call_errorhandler_writer(`
`4256`	`4256`	`}`
`4257`	`4257`	`if (need_to_grow) {`
`4258`	`4258`	`writer->overallocate = 1;`
`4259`		`- if (_PyUnicodeWriter_Prepare(writer, writer->min_length,`
	`4259`	`+ if (_PyUnicodeWriter_Prepare(writer, writer->min_length - writer->pos,`
`4260`	`4260`	`PyUnicode_MAX_CHAR_VALUE(repunicode)) == -1)`
`4261`	`4261`	`goto onError;`
`4262`	`4262`	`}`
`@@ -6085,9 +6085,7 @@ _PyUnicode_DecodeUnicodeEscape(const char *s,`
`6085`	`6085`	`&writer)) {`
`6086`	`6086`	`goto onError;`
`6087`	`6087`	`}`
`6088`		`- if (_PyUnicodeWriter_Prepare(&writer, writer.min_length, 127) < 0) {`
`6089`		`- goto onError;`
`6090`		`- }`
	`6088`	`+ assert(end - s <= writer.size - writer.pos);`
`6091`	`6089`
`6092`	`6090`	`#undef WRITE_ASCII_CHAR`
`6093`	`6091`	`#undef WRITE_CHAR`
`@@ -6364,9 +6362,7 @@ PyUnicode_DecodeRawUnicodeEscape(const char *s,`
`6364`	`6362`	`&writer)) {`
`6365`	`6363`	`goto onError;`
`6366`	`6364`	`}`
`6367`		`- if (_PyUnicodeWriter_Prepare(&writer, writer.min_length, 127) < 0) {`
`6368`		`- goto onError;`
`6369`		`- }`
	`6365`	`+ assert(end - s <= writer.size - writer.pos);`
`6370`	`6366`
`6371`	`6367`	`#undef WRITE_CHAR`
`6372`	`6368`	`}`