postgresql/src
Tom Lane 7e09b504d0 Make printf("%s", NULL) print "(null)" instead of crashing.
We previously took a hard-line attitude that callers should never print
a null string pointer, and doing so is worthy of an assertion failure
or crash.  However, we've long since flushed out any easy-to-find bugs
of that nature.  What remains is a lot of code that perhaps could fail
that way in hard-to-reach corner cases.  For example, in something as
simple as
    ereport(ERROR,
            (errcode(ERRCODE_UNDEFINED_OBJECT),
             errmsg("constraint \"%s\" for table \"%s\" does not exist",
                    conname, get_rel_name(relid))));
one must wonder whether it's completely guaranteed that get_rel_name
cannot return NULL in this context.  If such a situation did occur,
the existing policy converts what might be a pretty minor bug into
a server crash condition.  This is not good for robustness.

Hence, let's follow the lead of glibc and print "(null)" instead
of failing.  We should, of course, still consider it a bug if that
behavior is reachable in ordinary use; but crashing seems less
desirable than not crashing.

This fix works across-the-board in v12 and up, where we always use
src/port/snprintf.c.  Before that, on most platforms we're at the mercy
of the local libc, but it appears that Solaris 10 is the only supported
platform where we'd still get a crash.  Most other platforms such as
*BSD, macOS, and Solaris 11 have adopted glibc's behavior at some
point.  (AIX and HPUX just print "" not "(null)", but that's close
enough.)  I've not checked what Windows' native printf would do, but
it doesn't matter because we've long used snprintf.c on that platform.

In v12 and up, also const-ify related code so that we're not casting
away const on the constant string.  This is just neatnik-ism, since
next to no compilers will warn about that.

Discussion: https://postgr.es/m/17098-b960f3616c861f83@postgresql.org
2021-07-24 13:41:17 -04:00
..
backend Robustify tuplesort's free_sort_tuple function 2021-07-13 13:32:10 +12:00
bin Work around portability issue with newer versions of mktime(). 2021-06-13 14:32:42 -04:00
common Replace use of sys_siglist[] with strsignal(). 2020-07-15 22:05:13 -04:00
fe_utils Fix incautious handling of possibly-miscoded strings in client code. 2021-06-07 14:15:25 -04:00
include Update configure's probe for libldap to work with OpenLDAP 2.5. 2021-07-09 12:38:55 -04:00
interfaces Don't use abort(3) in libpq's fe-print.c. 2021-06-28 14:17:42 -04:00
makefiles Select CFLAGS_SL at configure time, not in platform-specific Makefiles. 2019-10-21 12:32:36 -04:00
pl Fix corner-case uninitialized-variable issues in plpgsql. 2021-07-20 13:01:48 -04:00
port Make printf("%s", NULL) print "(null)" instead of crashing. 2021-07-24 13:41:17 -04:00
template Further tweaking of PG_SYSROOT heuristics for macOS. 2021-01-20 12:07:52 -05:00
test Fix numeric_mul() overflow due to too many digits after decimal point. 2021-07-10 12:51:22 +01:00
timezone Update time zone data files to tzdata release 2021a. 2021-01-24 16:29:48 -05:00
tools fix syntax error 2021-05-28 09:36:10 -04:00
tutorial tutorial: land height is "elevation", not "altitude" 2021-03-10 20:25:18 -05:00
.gitignore Convert cvsignore to gitignore, and add .gitignore for build targets. 2010-09-22 12:57:04 +02:00
bcc32.mak Autoconfiscate selection of 64-bit int type for 64-bit large object API. 2012-10-07 21:52:43 -04:00
DEVELOPERS Replace a couple of references to files that no longer exist in the source 2009-05-04 08:08:47 +00:00
Makefile Install TAP test infrastructure so it's available for extension testing. 2016-09-23 15:50:00 -04:00
Makefile.global.in Fix prove_installcheck to use correct paths when used with PGXS 2021-07-01 09:01:36 -04:00
Makefile.shlib Ensure static libraries have correct mod time even if ranlib messes it up. 2018-11-29 15:53:44 -05:00
nls-global.mk nls-global.mk: search build dir for source files, too 2016-06-07 18:55:18 -04:00
win32.mak Autoconfiscate selection of 64-bit int type for 64-bit large object API. 2012-10-07 21:52:43 -04:00