Tweak the handling of $GDBHISTSIZE edge cases [PR gdb/16999]

When GDB reads a nonsensical value for the GDBHISTSIZE environment
variable, i.e. one that is non-numeric or negative, GDB then sets its
history size to 0.  This behavior is annoying and also inconsistent
with the behavior of bash.

This patch makes the behavior of invalid GDBHISTSIZE consistent with how
bash handles HISTSIZE.  When we encounter a null or out-of-range
GDBHISTSIZE (outside of [0, INT_MAX]) we now set the history size to
unlimited instead of 0.  When we encounter a non-numeric GDBHISTSIZE we
do nothing.

gdb/ChangeLog:

	PR gdb/16999
	* NEWS: Mention new GDBHISTSIZE behavior.
	* top.c (init_history): For null or out-of-range GDBHISTSIZE,
	set history size to unlimited.  Ignore non-numeric GDBHISTSIZE.

gdb/doc/ChangeLog:

	PR gdb/16999
	* gdb.texinfo (Command History): Mention new GDBHISTSIZE
	behavior.

gdb/testsuite/ChangeLog:

	PR gdb/16999
	* gdb.base/gdbhistsize-history.exp: New test.
This commit is contained in:
Patrick Palka 2015-05-12 06:50:26 -04:00
parent b58c513b79
commit bc460514b9
7 changed files with 118 additions and 17 deletions

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@ -1,3 +1,10 @@
2015-06-17 Patrick Palka <patrick@parcs.ath.cx>
PR gdb/16999
* NEWS: Mention new GDBHISTSIZE behavior.
* top.c (init_history): For null or out-of-range GDBHISTSIZE,
set history size to unlimited. Ignore non-numeric GDBHISTSIZE.
2015-06-17 Patrick Palka <patrick@parcs.ath.cx>
* NEWS: Mention that GDBHISTSIZE is read instead of HISTSIZE.

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@ -64,7 +64,9 @@
* The HISTSIZE environment variable is no longer read when determining
the size of GDB's command history. GDB now instead reads the dedicated
GDBHISTSIZE environment variable.
GDBHISTSIZE environment variable. Setting GDBHISTSIZE to "-1" or to "" now
disables truncation of command history. Non-numeric values of GDBHISTSIZE
are ignored.
* Guile Scripting

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@ -1,3 +1,9 @@
2015-06-17 Patrick Palka <patrick@parcs.ath.cx>
PR gdb/16999
* gdb.texinfo (Command History): Mention new GDBHISTSIZE
behavior.
2015-06-17 Patrick Palka <patrick@parcs.ath.cx>
* gdb.texinfo (Command History): Replace occurrences of HISTSIZE

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@ -22639,10 +22639,11 @@ Stop recording command history in a file.
@item set history size @var{size}
@itemx set history size unlimited
Set the number of commands which @value{GDBN} keeps in its history list.
This defaults to the value of the environment variable
@code{GDBHISTSIZE}, or to 256 if this variable is not set. If @var{size}
is @code{unlimited}, the number of commands @value{GDBN} keeps in the
history list is unlimited.
This defaults to the value of the environment variable @env{GDBHISTSIZE}, or
to 256 if this variable is not set. Non-numeric values of @env{GDBHISTSIZE}
are ignored. If @var{size} is @code{unlimited} or if @env{GDBHISTSIZE} is a
negative number, the number of commands @value{GDBN} keeps in the history list
is unlimited.
@end table
History expansion assigns special meaning to the character @kbd{!}.

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@ -1,3 +1,8 @@
2015-06-17 Patrick Palka <patrick@parcs.ath.cx>
PR gdb/16999
* gdb.base/gdbhistsize-history.exp: New test.
2015-06-17 Patrick Palka <patrick@parcs.ath.cx>
* gdb.base/gdbinit-history.exp: Replace occurrences of HISTSIZE

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@ -0,0 +1,70 @@
# Copyright 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.
# Test the setting of "history size" via the GDBHISTSIZE environment variable
# Check that the history size is properly set to SIZE when the environment
# variable ENV_VAR is set to GDBHISTSIZE.
proc test_histsize_history_setting { histsize size { env_var "GDBHISTSIZE" } } {
global env
set have_old_gdbhistsize 0
if [info exists env($env_var)] {
set have_old_gdbhistsize 1
set old_gdbhistsize $env($env_var)
}
set env($env_var) $histsize
with_test_prefix "histsize=$histsize" {
gdb_exit
gdb_start
gdb_test "show history size" "The size of the command history is $size."
if { $size == "0" } {
gdb_test_no_output "show commands"
} elseif { $size != "1" } {
gdb_test "show commands" \
" . show history size\r\n . show commands"
}
if { $have_old_gdbhistsize } {
set env($env_var) $old_gdbhistsize
} else {
unset env($env_var)
}
}
}
test_histsize_history_setting "" "unlimited"
test_histsize_history_setting "0" "0"
test_histsize_history_setting "20" "20"
test_histsize_history_setting " 20 " "20"
test_histsize_history_setting "-5" "unlimited"
# Test defaulting to 256 upon encountering a non-numeric GDBHISTSIZE.
test_histsize_history_setting "not_an_integer" "256"
test_histsize_history_setting "10zab" "256"
test_histsize_history_setting "-5ab" "256"
# A huge number (hopefully larger than INT_MAX)
test_histsize_history_setting "99999999999999999999999999999999999" "unlimited"
# We no longer read HISTSIZE
test_histsize_history_setting "50" "256" "HISTSIZE"

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@ -1684,21 +1684,31 @@ init_history (void)
tmpenv = getenv ("GDBHISTSIZE");
if (tmpenv)
{
int var;
long var;
char *endptr;
var = atoi (tmpenv);
if (var < 0)
{
/* Prefer ending up with no history rather than overflowing
readline's history interface, which uses signed 'int'
everywhere. */
var = 0;
}
tmpenv = skip_spaces (tmpenv);
var = strtol (tmpenv, &endptr, 10);
endptr = skip_spaces (endptr);
history_size_setshow_var = var;
/* If GDBHISTSIZE is non-numeric then ignore it. If GDBHISTSIZE is the
empty string, a negative number or a huge positive number (larger than
INT_MAX) then set the history size to unlimited. Otherwise set our
history size to the number we have read. This behavior is consistent
with how bash handles HISTSIZE. */
if (*endptr != '\0')
;
else if (*tmpenv == '\0'
|| var < 0
|| var > INT_MAX)
history_size_setshow_var = -1;
else
history_size_setshow_var = var;
}
/* If the init file hasn't set a size yet, pick the default. */
else if (history_size_setshow_var == -2)
/* If neither the init file nor GDBHISTSIZE has set a size yet, pick the
default. */
if (history_size_setshow_var == -2)
history_size_setshow_var = 256;
set_readline_history_size (history_size_setshow_var);