Some POSIX time zones are not handled correctly #7690
Description
Basic Infos
- This issue complies with the issue POLICY doc.
- I have read the documentation at readthedocs and the issue is not addressed there.
- I have tested that the issue is present in current master branch (aka latest git).
- I have searched the issue tracker for a similar issue.
- If there is a stack dump, I have decoded it.
- I have filled out all fields below.
Platform
- Hardware: [ESP-12]
- Core Version: [2.7.4]
- Development Env: [Arduino IDE]
- Operating System: [Windows]
Settings in IDE
- Module: [Generic ESP8266 Module]
- Flash Mode: [dio]
- Flash Size: [4MB]
- lwip Variant: [v2 Lower Memory]
- Reset Method: [nodemcu]
- Flash Frequency: [40Mhz]
- CPU Frequency: [80Mhz]
- Upload Using: [SERIAL]
- Upload Speed: [115200]
Problem Description
It looks as if some POSIX time zone strings may be being interpreted incorrectly when configured using:
configTime(const char* tz, const char* server1, const char* server2, const char* server3)or
setTZ(const char* tz)The following examples have been taken from TZ.h:
The following are some of the values which demonstrate the issue:
#define TZ_America_Sao_PauloPSTR("<-03>3") // Offset by +03:00 instead of -03:00 #define TZ_Africa_CasablancaPSTR("<+01>-1") // Offset by -01:00 instead of +01:00 #define TZ_America_AsuncionPSTR("<-04>4<-03>,M10.1.0/0,M3.4.0/0") // Offset by +4:00 instead of -03:00This pattern appears consistent for all time zones which are defined in this format.
By contrast the following (also taken from TZ.h) do not exhibit this issue:
#define TZ_America_Los_AngelesPSTR("PST8PDT,M3.2.0,M11.1.0") // Offset by -08:00 #define TZ_Europe_RomePSTR("CET-1CEST,M3.5.0,M10.5.0/3") // Offset by +01:00 #define TZ_Europe_KaliningradPSTR("EET-2") // Offset by +02:00All of the examples above were tested today @ ~1604351488 unix timestamp.
MCVE Sketch
#ifndef STASSID #define STASSID "VM723402-2G" #define STAPSK "gmwscxnu" #endif #include <TZ.h> #define MYTZ TZ_America_Sao_Paulo #include <ESP8266WiFi.h> #include <coredecls.h> #include <PolledTimeout.h> #include <time.h> #include <sys/time.h> extern "C" int clock_gettime(clockid_t unused, struct timespec *tp); static time_t now; static esp8266::polledTimeout::periodicMs showTimeNow(5000); String toISOString(tm* time) { char time_string[25]; strftime(time_string, 25, "%FT%T", time); return String(time_string); } void showTime() { now = time(nullptr); Serial.print("gmtime: "); Serial.println(toISOString(gmtime(&now))); Serial.print("localtime: "); Serial.println(toISOString(localtime(&now))); } void time_is_set_scheduled() { showTime(); } void setup() { Serial.begin(115200); Serial.println("Starting..."); settimeofday_cb(time_is_set_scheduled); // Set the timezone configTime(MYTZ, "pool.ntp.org"); // start network WiFi.persistent(false); WiFi.mode(WIFI_STA); WiFi.begin(STASSID, STAPSK); } void loop() { if (showTimeNow) { showTime(); } } Debug Messages
One example, when using TZ_America_Sao_Paulo, local time should be offset -03:00, instead it is offset +03:00:
gmtime: 2020-11-02T20:36:51 localtime: 2020-11-02T23:36:51 gmtime: 2020-11-02T20:36:56 localtime: 2020-11-02T23:36:56 gmtime: 2020-11-02T20:37:01 localtime: 2020-11-02T23:37:01 gmtime: 2020-11-02T20:37:06 localtime: 2020-11-02T23:37:06