The HISTSIZE environment variable is generally expected to be read by
shells, not by applications. Some distros for example globally export
HISTSIZE in /etc/profile -- with the intention that it only affects
shells -- and by doing so it renders useless GDB's own mechanism for
setting the history size via .gdbinit. Also, annoyances may arise when
HISTSIZE is not interpreted the same way by the shell and by GDB, e.g.
PR gdb/16999. That can always be fixed on a shell-by-shell basis but it
may be impossible to be consistent with the behavior of all shells at
once. Finally it just makes sense to not confound shell environment
variables with application environment variables.
gdb/ChangeLog:
* NEWS: Mention that GDBHISTSIZE is read instead of HISTSIZE.
* top.c (init_history): Read from GDBHISTSIZE instead of
HISTSIZE.
(init_main): Refer to GDBHISTSIZE instead of HISTSIZE.
gdb/doc/ChangeLog:
* gdb.texinfo (Command History): Replace occurrences of HISTSIZE
with GDBHISTSIZE.
gdb/testsuite/ChangeLog:
* gdb.base/gdbinit-history.exp: Replace occurrences of HISTSIZE
with GDBHISTSIZE.
* gdb.base/readline.exp: Likewise.
We still do not handle "set history size unlimited" correctly. In
particular, after writing to the history file, we truncate the history
even if it is unlimited.
This patch makes sure that we do not call history_truncate_file() if the
history is not stifled (i.e. if it's unlimited). This bug causes the
history file to be truncated to zero on exit when one has "set history
size unlimited" in their gdbinit file. Although this code exists in GDB
7.8, the bug is masked by a pre-existing bug that's been only fixed in
GDB 7.9 (PR gdb/17820).
gdb/ChangeLog:
* top.c (gdb_safe_append_history): Do not call
history_truncate_file if the history is not stifled.
gdb/testsuite/ChangeLog:
* gdb.base/gdbinit-history.exp: Add test case to check that
an unlimited history file does not get truncated on exit.
Use with_test_prefix to avoid duplicating test names when calling
the procedure test_gdbinit_history_setting multiple times.
gdb/testsuite/ChangeLog:
* gdb.base/gdbinit-history.exp (test_gdbinit_history_setting):
Use with_test_prefix.
Some buildslaves are showing that this test is failing. E.g.,:
https://sourceware.org/ml/gdb-testers/2015-q2/msg04164.html
The issue is that HISTSIZE is set to 1000 in the environment that runs
the tests (that's the default in Fedora, set in /etc/profile).
We can trivially reproduce it with:
$ HISTSIZE=1000 make check RUNTESTFLAGS="gdbinit-history.exp"
(...)
Running /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.base/gdbinit-history.exp ...
FAIL: gdb.base/gdbinit-history.exp: show history size
FAIL: gdb.base/gdbinit-history.exp: show history size
FAIL: gdb.base/gdbinit-history.exp: show commands
gdb.log shows:
...
(gdb) set height 0
(gdb) set width 0
(gdb) show history size
The size of the command history is 1000.
(gdb) FAIL: gdb.base/gdbinit-history.exp: show history size
gdb/testsuite/ChangeLog:
2015-05-19 Pedro Alves <palves@redhat.com>
* gdb.base/gdbinit-history.exp (test_gdbinit_history_setting):
Save the whole env array instead of just HOME. Unset HISTSIZE in
the environment while testing. Restore whole environment
afterwards.
This patch is a comprehensive fix for PR 17820 which reports that
using "set history size unlimited" inside one's gdbinit file doesn't
really work.
There are three small changes in this patch. The most important change
this patch makes is to decode the argument of the "size" subcommand
using add_setshow_zuinteger_unlimited_cmd() instead of using
add_setshow_uinteger_cmd(). The new decoder takes an int * and maps
unlimited to -1 whereas the old decoder takes an unsigned int * and maps
unlimited to UINT_MAX. Using the new decoder simplifies our handling of
unlimited and makes it easier to interface with readline which itself
expects a signed-int history size.
The second change is the factoring of the [stifle|unstifle]_history logic
into a common function which is now used by both init_history() and
set_history_size_command(). This is technically the change that fixes
the PR itself.
Thirdly, this patch initializes history_size_setshow_var to -2 to mean
that the variable has not been set yet. Now init_history() tests for -2
instead of 0 to determine whether to give the variable a default value.
This means that having "set history size 0" in one's gdbinit file will
actually keep the history size at 0 and not reset it to 256.
gdb/ChangeLog:
PR gdb/17820
* top.c (history_size_setshow_var): Change type to signed.
Initialize to -2. Update documentation.
(set_readline_history_size): Define.
(set_history_size_command): Use it. Remove logic for handling
out-of-range sizes.
(init_history): Use set_readline_history_size(). Test for a
value of -2 instead of 0 when determining whether to set a
default history size.
(init_main): Decode the argument of the "size" command as a
zuinteger_unlimited.
gdb/testsuite/ChangeLog:
PR gdb/17820
* gdb.base/gdbinit-history.exp: New test.
* gdb.base/gdbinit-history/unlimited/.gdbinit: New file.
* gdb.base/gdbinit-history/zero/.gdbinit: New file.
