Further portability hacking in pg_upgrade's test script.

I blew the dust off a Bourne shell (file date 1996, yea verily) and
tried to run test.sh with it.  It mostly worked, but I found that the
temp-directory creation code introduced by commit be76a6d39 was not
compatible, for a couple of reasons: this shell thinks "set -e" should
force an exit if a command within backticks fails, and it also thinks code
within braces should be executed by a sub-shell, meaning that variable
settings don't propagate back up to the parent shell.  In view of Victor
Wagner's report that Solaris is still using pre-POSIX shells, seems like
we oughta make this case work.  It's not like the code is any less
idiomatic this way; the prior coding technique appeared nowhere else.

(There is a remaining bash-ism here, which is that $RANDOM doesn't do
what the code hopes in non-bash shells.  But the use of $$ elsewhere in
that path should be enough to ensure uniqueness and some amount of
randomness, so I think it's okay as-is.)

Back-patch to all supported branches, as the previous commit was.

Discussion: https://postgr.es/m/20180720153820.69e9ae6c@fafnir.local.vm

diff --git a/src/bin/pg_upgrade/test.sh b/src/bin/pg_upgrade/test.sh
index 31a8581b14678ea86ab7c6cc3fd18a5515ce6b5b..af428a9df802671597118c70e4fda8866fa238c6 100644 (file)
--- a/src/bin/pg_upgrade/test.sh
+++ b/src/bin/pg_upgrade/test.sh
@@ -42,20 +42,18 @@ case $testhost in
                # script; the outcome mimics pg_regress.c:make_temp_sockdir().
                PGHOST=$PG_REGRESS_SOCK_DIR
                if [ "x$PGHOST" = x ]; then
-                       {
-                               dir=`(umask 077 &&
-                                         mktemp -d /tmp/pg_upgrade_check-XXXXXX) 2>/dev/null` &&
-                               [ -d "$dir" ]
-                       } ||
-                       {
+                       set +e
+                       dir=`(umask 077 &&
+                                 mktemp -d /tmp/pg_upgrade_check-XXXXXX) 2>/dev/null`
+                       if [ ! -d "$dir" ]; then
                                dir=/tmp/pg_upgrade_check-$$-$RANDOM
                                (umask 077 && mkdir "$dir")
-                       } ||
-                       {
-                               echo "could not create socket temporary directory in \"/tmp\""
-                               exit 1
-                       }
-
+                               if [ ! -d "$dir" ]; then
+                                       echo "could not create socket temporary directory in \"/tmp\""
+                                       exit 1
+                               fi
+                       fi
+                       set -e
                        PGHOST=$dir
                        trap 'rm -rf "$PGHOST"' 0
                        trap 'exit 3' 1 2 13 15