[Noah Misch <noah@leadboat.com>]

When "make check TEMP_CONFIG=<(echo break_me=on)" spawns a postmaster that
fails startup, we detect that with "pg_regress: postmaster did not respond
within 60 seconds".  pg_regress has a kill(postmaster_pid, 0) intended to
detect this case faster.  Since kill(ZOMBIE-PID, 0) succeeds[1], that test is
ineffective.  The fix, attached, is to instead test waitpid(), like pg_ctl's
wait_for_postmaster() does.

[1] Search for "zombie" in
http://pubs.opengroup.org/onlinepubs/9699919799/functions/kill.html

Attachments:

pg_regress-dead-postmaster-v1.patch (text/x-diff, 535B) download
diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 63fe689..2c46941 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -2414,7 +2414,7 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
 			 * Fail immediately if postmaster has exited
 			 */
 #ifndef WIN32
-			if (kill(postmaster_pid, 0) != 0)
+			if (waitpid(postmaster_pid, NULL, WNOHANG) == postmaster_pid)
 #else
 			if (WaitForSingleObject(postmaster_pid, 0) == WAIT_OBJECT_0)
 #endif