PR mi/18833 gdb.execute ("set param value", to_string=True) will crash gdb if using MI

gdb/ChangeLog:

	* cli/cli-logging.c (pop_output_files): Don't restore redirection
	if MI-like.
	* mi/mi-out.c: #include "vec.h".
	(ui_filep): New type.
	(DEV_VEC_P (ui_filep)): New type.
	(struct ui_out_data) <buffer, original_buffer>: Delete.
	(struct ui_out_data) <streams>: New member.
	(mi_ui_out_impl): Add data_destroy field.
	(mi_field_string, mi_field_fmt): Update.
	(mi_flush, mi_redirect, field_separator): Update.
	(mi_open, mi_close): Update.
	(mi_out_buffered, mi_out_rewind, mi_out_put): Update.
	(mi_out_data_ctor, mi_out_data_dtor): New functions.
	(mi_out_new): Call mi_out_data_ctor.

testsuite/gdb/ChangeLog:

	* lib/gdb.exp (skip_python_tests_prompt): Renamed from
	skip_python_tests.  New arg prompt_regexp.
	(skip_python_tests): New function.
	* lib/mi-support.exp (mi_skip_python_tests): New function.
	* gdb.python/py-mi-objfile-gdb.py: New file.
	* gdb.python/py-mi-objfile.c: New file.
	* gdb.python/py-mi-objfile.exp: New file.

1 files changed, 27 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.python/py-mi-objfile-gdb.py b/gdb/testsuite/gdb.python/py-mi-objfile-gdb.py
new file mode 100644
index 0000000..6e41773
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-mi-objfile-gdb.py
@@ -0,0 +1,27 @@
+# Copyright (C) 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite.
+
+import gdb
+
+# PR 18833
+# We want to have two levels of redirection while MI is current_uiout.
+# This will create one for to_string=True and then another for the
+# parameter change notification.
+gdb.execute("set width 101", to_string=True)
+# And finally a command that will use the original MI stream, which in a
+# buggy gdb will use just-freed data.
+gdb.execute("list")