[pypy-commit] pypy py3.6: Fix bpo-25862

[rlamy]

Author: Ronan Lamy <ronan.lamy at gmail.com>
Branch: py3.6
Changeset: r97104:8b8aaf492f23
Date: 2019-08-08 15:59 +0100
http://bitbucket.org/pypy/pypy/changeset/8b8aaf492f23/

Log:	Fix bpo-25862

diff --git a/pypy/module/_io/interp_textio.py b/pypy/module/_io/interp_textio.py
--- a/pypy/module/_io/interp_textio.py
+++ b/pypy/module/_io/interp_textio.py
@@ -746,6 +746,7 @@
         check_decoded(space, w_decoded)
         w_result = space.newtext(self.decoded.get_chars(-1))
         w_final = space.add(w_result, w_decoded)
+        self.decoded.reset()
         self.snapshot = None
         return w_final
 
@@ -892,6 +893,7 @@
         if needflush:
             space.call_method(self.w_buffer, "flush")
 
+        self.decoded.reset()
         self.snapshot = None
 
         if self.w_decoder:
diff --git a/pypy/module/_io/test/test_textio.py b/pypy/module/_io/test/test_textio.py
--- a/pypy/module/_io/test/test_textio.py
+++ b/pypy/module/_io/test/test_textio.py
@@ -458,6 +458,18 @@
         t.__init__(_io.BytesIO())
         assert t.read(0) == u''
 
+    def test_issue25862(self):
+        # CPython issue #25862
+        # Assertion failures occurred in tell() after read() and write().
+        from _io import TextIOWrapper, BytesIO
+        t = TextIOWrapper(BytesIO(b'test'), encoding='ascii')
+        t.read(1)
+        t.read()
+        t.tell()
+        t = TextIOWrapper(BytesIO(b'test'), encoding='ascii')
+        t.read(1)
+        t.write('x')
+        t.tell()
 
 class AppTestIncrementalNewlineDecoder:
     def test_newline_decoder(self):