Merlin Moncure <[email protected]> writes:
> On Wed, Dec 16, 2015 at 1:29 PM, Tom Lane <[email protected]> wrote:
>> So I now think that print.c shouldn't be involved at all, and the right
>> thing to do is just have gets_interactive() invoke the resize function
>> immediately before calling readline(). That will still leave a window
>> for SIGWINCH to be missed, but it's a pretty tiny one.
> right -- agreed.
I tried that and found out that the first call dumps core because readline
hasn't been initialized yet. To fix that, we need an explicit call to
rl_initialize() instead of depending on readline() to do it for us.
So I arrive at the attached modified patch.
>> And somebody oughta report this as a libreadline bug ...
> See https://bugs.python.org/issue23735 for background. Apparently
> this is expected behavior (and we are far from the only ones
> complaining about it):
> "And so we reach where we are. If a SIGWINCH arrives while readline is
> not active, and the application using callback mode does not catch it and
> tell readline about the updated screen dimensions (rl_set_screen_size()
> exists for this purpose), readline will not know about the new size."
Meh. At the very least, this is a serious documentation failure on their
part, because their docs about interrupt handling look exactly the same
as before, to wit saying exactly the opposite of this.
regards, tom lane
diff --git a/configure b/configure
index 8c61390..5772d0e 100755
*** a/configure
--- b/configure
*************** if test x"$pgac_cv_var_rl_completion_app
*** 13232,13238 ****
$as_echo "#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1" >>confdefs.h
fi
! for ac_func in rl_completion_matches rl_filename_completion_function
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
--- 13232,13238 ----
$as_echo "#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1" >>confdefs.h
fi
! for ac_func in rl_completion_matches rl_filename_completion_function rl_reset_screen_size
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/configure.in b/configure.in
index b5868b0..44f832f 100644
*** a/configure.in
--- b/configure.in
*************** LIBS="$LIBS_including_readline"
*** 1635,1641 ****
if test "$with_readline" = yes; then
PGAC_VAR_RL_COMPLETION_APPEND_CHARACTER
! AC_CHECK_FUNCS([rl_completion_matches rl_filename_completion_function])
AC_CHECK_FUNCS([append_history history_truncate_file])
fi
--- 1635,1641 ----
if test "$with_readline" = yes; then
PGAC_VAR_RL_COMPLETION_APPEND_CHARACTER
! AC_CHECK_FUNCS([rl_completion_matches rl_filename_completion_function rl_reset_screen_size])
AC_CHECK_FUNCS([append_history history_truncate_file])
fi
diff --git a/src/bin/psql/input.c b/src/bin/psql/input.c
index e377104..c0c5524 100644
*** a/src/bin/psql/input.c
--- b/src/bin/psql/input.c
*************** gets_interactive(const char *prompt)
*** 65,70 ****
--- 65,81 ----
{
char *result;
+ /*
+ * Some versions of readline don't notice SIGWINCH signals that arrive
+ * when not actively reading input. The simplest fix is to always
+ * re-read the terminal size. This leaves a window for SIGWINCH to be
+ * missed between here and where readline() enables libreadline's
+ * signal handler, but that's probably short enough to be ignored.
+ */
+ #ifdef HAVE_RL_RESET_SCREEN_SIZE
+ rl_reset_screen_size();
+ #endif
+
/* Enable SIGINT to longjmp to sigint_interrupt_jmp */
sigint_interrupt_enabled = true;
*************** initializeInput(int flags)
*** 330,335 ****
--- 341,347 ----
char home[MAXPGPATH];
useReadline = true;
+ rl_initialize();
initialize_readline();
useHistory = true;
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index a20e0cd..16a272e 100644
*** a/src/include/pg_config.h.in
--- b/src/include/pg_config.h.in
***************
*** 428,433 ****
--- 428,436 ----
/* Define to 1 if you have the `rl_filename_completion_function' function. */
#undef HAVE_RL_FILENAME_COMPLETION_FUNCTION
+ /* Define to 1 if you have the `rl_reset_screen_size' function. */
+ #undef HAVE_RL_RESET_SCREEN_SIZE
+
/* Define to 1 if you have the <security/pam_appl.h> header file. */
#undef HAVE_SECURITY_PAM_APPL_H
--
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