From d724fe4838db898a323102e4f2981af90c9ea132 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Mon, 4 May 2009 22:27:05 -0700 Subject: [PATCH] model-checker: Revise advice on checking for duplicates. Until now the documentation on the model checker has advised checking for a duplicate state before checking for consistency, but in fact this can cause bugs to be missed if only some paths to a given state yield incorrect results. So revise the advice to check for consistency before checking for a duplicate state. --- src/libpspp/model-checker.h | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/src/libpspp/model-checker.h b/src/libpspp/model-checker.h index 1e756119..205c3fac 100644 --- a/src/libpspp/model-checker.h +++ b/src/libpspp/model-checker.h @@ -150,14 +150,12 @@ mc_name_operation (mc, "do operation %s", ...); clone = clone_foo (state); do_operation (clone); - if (!mc_discard_dup_state (mc, hash_foo (clone))) - { - if (!state_is_consistent (clone)) - mc_error (mc, "inconsistent state"); - mc_add_state (mc, clone); - } - else + if (!state_is_consistent (clone)) + mc_error (mc, "inconsistent state"); + if (mc_discard_dup_state (mc, hash_foo (clone))) destroy_foo (clone); + else + mc_add_state (mc, clone); } } @@ -204,10 +202,10 @@ the metadata. mc_discard_dup_state may be called before or after - checking for consistency, but calling it first avoids - wasting time checking duplicate states for - consistency, which again can be a significant - performance boost. + checking for consistency. Calling it after checking + may make checking a given number of unique states + take longer, but it also ensures that all paths to a + given state produce correct results. - The mc_error function reports errors. It may be called as many times as desired to report each kind -- 2.30.2