Memory Leak when calling current_zone()

[satishbhat-umd]

=================================================================
==32643==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 72 byte(s) in 1 object(s) allocated from:
#0 0x568e50 in calloc (/build/sbhat/Laser/BT.BelvedereExchange/Tests/BT.BelvedereExchange.Tests+0x568e50)
#1 0x7fffe1767163 (/lib64/libnsspem.so+0x15163)

Direct leak of 72 byte(s) in 1 object(s) allocated from:
#0 0x568e50 in calloc (/build/sbhat/Laser/BT.BelvedereExchange/Tests/BT.BelvedereExchange.Tests+0x568e50)
#1 0x7fffe8ef4773 (/lib64/libnss3.so+0x75773)

Getting the following output when compiling using -fsanitize=address when the date::current_zone() fn is called

[HowardHinnant]

What OS/platform?

[satishbhat-umd]

CentOS 7.3

NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

[HowardHinnant]

Is it reproduceable in a small test such as:

#include "date/tz.h"

int
main()
{
    auto tz = date::current_zone();
}

And what build settings are you using (e.g. USE_OS_TZDB)?

[HowardHinnant]

Does it reproduce with this program?

#include "date/tz.h"

int
main()
{
    auto tz = date::locate_zone("Europe/Berlin");
}

[satishbhat-umd]

Reproduces in both cases and USE_OS_TZDB was not set when compiling the library (i.e. it will use a curl request to fetch the tzdb)

[HowardHinnant]

I'm not currently able to reproduce this on my platform. Can you use this tool to locate the source line in tz.cpp where the leaked memory is allocated?

[satishbhat-umd]

It appears to be allocated in the curl_init function. I see the curl_deleter struct is passed to the destructor of the CURL object, but it seems to only call curl_easy_cleanup(...) in operator(). If I add a call to ::curl_global_cleanup() after that and recompile the library, I am able to call current_zone() without any memory leaks.

[HowardHinnant]

Really nice detective work. I would not have found this.

Would you like for me to just fix it, or would you like to submit a P/R?

[satishbhat-umd]

Created a P/R here - #652

[HowardHinnant]

Fixed by #652