[Tarantool-patches] [PATCH] Fix wrong make_scoped_guard usage
Aleksandr Lyapunov
alyapunov at tarantool.org
Wed Jul 8 15:07:07 MSK 2020
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
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