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Pedro Alves d3d4baedb6 PR python/17372 - Python hangs when displaying help()
This is more of a readline/terminal issue than a Python one.

PR17372 is a regression in 7.8 caused by the fix for PR17072:

 commit 0017922d02
 Author: Pedro Alves <palves@redhat.com>
 Date:   Mon Jul 14 19:55:32 2014 +0100

    Background execution + pagination aborts readline/gdb

    gdb_readline_wrapper_line removes the handler after a line is
    processed.  Usually, we'll end up re-displaying the prompt, and that
    reinstalls the handler.  But if the output is coming out of handling
    a stop event, we don't re-display the prompt, and nothing restores the
    handler.  So the next input wakes up the event loop and calls into
    readline, which aborts.
...
    gdb/
    2014-07-14  Pedro Alves  <palves@redhat.com>

        PR gdb/17072
        * top.c (gdb_readline_wrapper_line): Tweak comment.
        (gdb_readline_wrapper_cleanup): If readline is enabled, reinstall
        the input handler callback.

The problem is that installing the input handler callback also preps
the terminal, putting it in raw mode and with echo disabled, which is
bad if we're going to call a command that assumes cooked/canonical
mode, and echo enabled, like in the case of the PR, Python's
interactive shell.  Another example I came up with that doesn't depend
on Python is starting a subshell with "(gdb) shell /bin/sh" from a
multi-line command.  Tests covering both these examples are added.

The fix is to revert the original fix for PR gdb/17072, and instead
restore the callback handler after processing an asynchronous target
event.

Furthermore, calling rl_callback_handler_install when we already have
some input in readline's line buffer discards that input, which is
obviously a bad thing to do while the user is typing.  No specific
test is added for that, because I first tried calling it even if the
callback handler was still installed and that resulted in hundreds of
failures in the testsuite.

gdb/
2014-10-29  Pedro Alves  <palves@redhat.com>

	PR python/17372
	* event-top.c (change_line_handler): Call
	gdb_rl_callback_handler_remove instead of
	rl_callback_handler_remove.
	(callback_handler_installed): New global.
	(gdb_rl_callback_handler_remove, gdb_rl_callback_handler_install)
	(gdb_rl_callback_handler_reinstall): New functions.
	(display_gdb_prompt): Call gdb_rl_callback_handler_remove and
	gdb_rl_callback_handler_install instead of
	rl_callback_handler_remove and rl_callback_handler_install.
	(gdb_disable_readline): Call gdb_rl_callback_handler_remove
	instead of rl_callback_handler_remove.
	* event-top.h (gdb_rl_callback_handler_remove)
	(gdb_rl_callback_handler_install)
	(gdb_rl_callback_handler_reinstall): New declarations.
	* infrun.c (reinstall_readline_callback_handler_cleanup): New
	cleanup function.
	(fetch_inferior_event): Install it.
	* top.c (gdb_readline_wrapper_line) Call
	gdb_rl_callback_handler_remove instead of
	rl_callback_handler_remove.
	(gdb_readline_wrapper_cleanup): Don't call
	rl_callback_handler_install.

gdb/testsuite/
2014-10-29  Pedro Alves  <palves@redhat.com>

	PR python/17372
	* gdb.python/python.exp: Test a multi-line command that spawns
	interactive Python.
	* gdb.base/multi-line-starts-subshell.exp: New file.
2014-10-29 17:29:26 +00:00
bfd Thix fixes an obvious coding error that led to a GDB crash on AIX or HPUX. 2014-10-29 17:17:32 +00:00
binutils Updated/new translations provided by the Translations Project. 2014-10-29 16:34:04 +00:00
config
cpu
elfcpp
etc
gas Updated/new translations provided by the Translations Project. 2014-10-29 16:34:04 +00:00
gdb PR python/17372 - Python hangs when displaying help() 2014-10-29 17:29:26 +00:00
gold [GOLD] Add gcc-4.9 libgomp symbols requiring --plt-thread-safe for power7 2014-10-22 08:10:47 +10:30
gprof Updated/new translations provided by the Translations Project. 2014-10-29 16:34:04 +00:00
include Refactoring/cleanup of nios2 opcodes and assembler code. 2014-10-23 09:54:15 -07:00
intl
ld Updated/new translations provided by the Translations Project. 2014-10-29 16:34:04 +00:00
libdecnumber
libiberty Use strtod instead of strtold in libiberty/d-demangle.c 2014-10-16 14:52:17 -07:00
opcodes Updated/new translations provided by the Translations Project. 2014-10-29 16:34:04 +00:00
readline
sim
texinfo
.cvsignore
.gitattributes
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ChangeLog src-release.sh: configure using --target. 2014-10-15 09:50:53 +02:00
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config.rpath
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COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
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depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
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Makefile.in
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src-release.sh src-release.sh: configure using --target. 2014-10-15 09:50:53 +02:00
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		   README for GNU development tools

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	setenv CC gcc
	./configure
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