[translation:ERROR] UnionError:

Offending annotations:
  SomeInstance(can_be_None=False, classdef=pypy.objspace.std.unicodeobject.W_UnicodeObject)
  SomeUnicodeString(no_nul=True)

In <FunctionGraph of (pypy.module._io.interp_win32consoleio:33)read_console_w at 0x2a74d110>:
<return block>
Processing block:
 block@781[buf_0...] is a <class 'rpython.flowspace.flowcontext.SpamBlock'>
 in (pypy.module._io.interp_win32consoleio:33)read_console_w
 containing the following operations:
       v951 = simple_call((function charp2str), buf_0)
 --end--
[translation] start debugger...
> c:\pypy\pypy\rpython\annotator\binaryop.py(93)union()
-> raise UnionError(obj1, obj2)


def read_console_w(space, handle, maxlen):
    err = 0
    sig = 0
    buf = lltype.malloc(rffi.CWCHARP.TO, maxlen, flavor='raw')
    readlen = 0
    try:
        if not buf:
            # Should return some kind of
            # null here but this results in a union error.
            return space.newutf8("",0)

        off = 0
        while off < maxlen:
            with lltype.scoped_alloc(rwin32.LPDWORD.TO, 1) as n:
                n[0] = rffi.cast(rffi.UINT, -1)
                len = min(rffi.cast(rffi.INT, maxlen - off),rffi.cast(rffi.INT, BUFSIZ))
                rwin32.SetLastError_saved(0)
                res = rwin32.ReadConsoleW(handle, buf[off], len, n, rffi.NULL)

                err = rwin32.GetLastError_saved()

                if not res:
                    break

                if n[0] == -1 and err == rwin32.ERROR_OPERATION_ABORTED:
                    break

                if n[0] == 0:
                    if err != rwin32.ERROR_OPERATION_ABORTED:
                        break
                    err = 0
                    hInterruptEvent = sigintevent()
                    if rwin32.WaitForSingleObjectEx(hInterruptEvent, 100, False) == rwin32.WAIT_OBJECT_0:
                        rwin32.ResetEvent(hInterruptEvent)
                        space.getexecutioncontext().checksignals()

                readlen += n[0]

                # We didn't manage to read the whole buffer
                # don't try again as it will just block
                if n[0] < len:
                    break

                # We read a new line
                if buf[readlen -1] == u'\n':
                    break

                with lltype.scoped_alloc(rwin32.LPWORD.TO, 1) as char_type:
                    if (off + BUFSIZ) >= maxlen and \
                        rwin32.GetStringTypeW(rwin32.CT_CTYPE3, buf[readlen[0] - 1], 1, char_type) and \
                        char_type == rwin32.C3_HIGHSURROGATE:
                        maxlen += 1
                        newbuf = lltype.malloc(rffi.CWCHARP.TO, maxlen, flavor='raw')
                        lltype.free(buf, flavor='raw')
                        buf = newbuf
                        off += n[0]
                        continue
                    off += BUFSIZ
        if err:
            lltype.free(buf, flavor='raw')
            return space.newutf8("",0)

        if readlen > 0 and buf == u'\x1a':
            lltype.free(buf, flavor='raw')
            buf = lltype.malloc(rffi.CWCHARP.TO, 1, flavor='raw')
            buf[0] = '\0'
            readlen = 0
        return rffi.wcharp2unicode(buf)
    except:
        lltype.free(buf, flavor='raw')
        return space.newutf8("",0)