From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpng2.m.smailru.net (smtpng2.m.smailru.net [94.100.179.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 7AA28445321 for ; Wed, 8 Jul 2020 15:07:08 +0300 (MSK) From: Aleksandr Lyapunov Date: Wed, 8 Jul 2020 15:07:07 +0300 Message-Id: <1594210027-332-2-git-send-email-alyapunov@tarantool.org> In-Reply-To: <1594210027-332-1-git-send-email-alyapunov@tarantool.org> References: <1594210027-332-1-git-send-email-alyapunov@tarantool.org> Subject: [Tarantool-patches] [PATCH] Fix wrong make_scoped_guard usage List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: tarantool-patches@dev.tarantool.org The common pitfall of using a lambda is wrong type of capture - by value instead of by reference. The simple example is: struct sequence_def *new_def = NULL; auto def_guard = make_scoped_guard([=] { free(new_def); }); // initialize new_def The problem is that the lambda captures pointer by value, that is NULL and will remain NULL in the lambda while new_def is successfully initialized in function scope. The patch fixes the problem above and a couple of similar mistakes. --- src/box/alter.cc | 4 ++-- src/main.cc | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/box/alter.cc b/src/box/alter.cc index bb42548..3109fb4 100644 --- a/src/box/alter.cc +++ b/src/box/alter.cc @@ -3560,7 +3560,7 @@ on_replace_dd_func(struct trigger * /* trigger */, void *event) * definition to support upgrade script. */ struct func_def *old_def = NULL, *new_def = NULL; - auto guard = make_scoped_guard([=] { + auto guard = make_scoped_guard([&old_def, &new_def] { free(old_def); free(new_def); }); @@ -4431,7 +4431,7 @@ on_replace_dd_sequence(struct trigger * /* trigger */, void *event) struct tuple *new_tuple = stmt->new_tuple; struct sequence_def *new_def = NULL; - auto def_guard = make_scoped_guard([=] { free(new_def); }); + auto def_guard = make_scoped_guard([&new_def] { free(new_def); }); struct sequence *seq; if (old_tuple == NULL && new_tuple != NULL) { /* INSERT */ diff --git a/src/main.cc b/src/main.cc index 2c96391..e622042 100644 --- a/src/main.cc +++ b/src/main.cc @@ -729,7 +729,7 @@ main(int argc, char **argv) /* Lua interpeter options, e.g. -e and -l */ int optc = 0; const char **optv = NULL; - auto guard = make_scoped_guard([=]{ if (optc) free(optv); }); + auto guard = make_scoped_guard([&optc, &optv]{ if (optc) free(optv); }); static struct option longopts[] = { {"help", no_argument, 0, 'h'}, -- 2.7.4