postgresql/src
Tom Lane 3779ac62d7 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 Make ALTER TRIGGER RENAME consistent for partitioned tables 2021-07-22 18:33:47 -04:00
bin Add missing header declarations for pg_basebackup and pg_{dump,restore} 2021-07-24 19:05:14 +09:00
common Simplify error handing of jsonapi.c for the frontend 2021-07-02 09:35:12 +09:00
fe_utils Unify parsing logic for command-line integer options 2021-07-24 18:35:03 +09:00
include Fix failure of some headers to compile "standalone". 2021-07-24 11:34:33 -04:00
interfaces Install properly fe-auth-sasl.h 2021-07-14 10:37:26 +09:00
makefiles Add NO_INSTALL option to pgxs 2021-05-27 13:58:29 +02:00
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 12:07:23 -05:00
test Make new test immune to collation 2021-07-23 11:52:48 -04:00
timezone Update time zone data files to tzdata release 2021a. 2021-01-24 16:29:47 -05:00
tools Ensure HAVE_DECL_XXX macros in MSVC builds match those in Unix. 2021-07-15 11:00:43 -04:00
tutorial doc: Prefer explicit JOIN syntax over old implicit syntax in tutorial 2021-04-08 10:51:26 +02:00
.gitignore
DEVELOPERS
Makefile Remove the option to build thread_test.c outside configure. 2020-10-21 12:08:48 -04:00
Makefile.global.in Fix prove_installcheck to use correct paths when used with PGXS 2021-07-01 09:02:46 -04:00
Makefile.shlib Add PostgreSQL home page to --help output 2020-02-28 13:12:21 +01:00
nls-global.mk Add errhint_plural() function and make use of it 2021-03-31 09:16:25 +02:00