[Python-checkins] bpo-40686: Fix compiler warnings on _zoneinfo.c (GH-23614) (GH-23804)

[vstinner]

https://github.com/python/cpython/commit/7492b55ea0ca993c353b6373341b92e40faa9c4d
commit: 7492b55ea0ca993c353b6373341b92e40faa9c4d
branch: 3.9
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: vstinner <vstinner at python.org>
date: 2020-12-16T17:33:05+01:00
summary:

bpo-40686: Fix compiler warnings on _zoneinfo.c (GH-23614) (GH-23804)

"uint8_t day" is unsigned and so "day < 0" test is always true.
Remove the test to fix the following warnings on Windows:

modules\_zoneinfo.c(1224): warning C4068: unknown pragma
modules\_zoneinfo.c(1225): warning C4068: unknown pragma
modules\_zoneinfo.c(1227): warning C4068: unknown pragma
(cherry picked from commit aefb69b23f056c61e82ad228d950f348de090c70)

Co-authored-by: Victor Stinner <vstinner at python.org>

Co-authored-by: Victor Stinner <vstinner at python.org>

files:
M Modules/_zoneinfo.c

diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
index 2cee65fac6dd0..fafb6b01df371 100644
--- a/Modules/_zoneinfo.c
+++ b/Modules/_zoneinfo.c
@@ -171,7 +171,7 @@ static void
 update_strong_cache(const PyTypeObject *const type, PyObject *key,
                     PyObject *zone);
 static PyObject *
-zone_from_strong_cache(const PyTypeObject *const type, PyObject *key);
+zone_from_strong_cache(const PyTypeObject *const type, PyObject *const key);
 
 static PyObject *
 zoneinfo_new_instance(PyTypeObject *type, PyObject *key)
@@ -1219,15 +1219,9 @@ calendarrule_new(uint8_t month, uint8_t week, uint8_t day, int8_t hour,
         return -1;
     }
 
-    // day is an unsigned integer, so day < 0 should always return false, but
-    // if day's type changes to a signed integer *without* changing this value,
-    // it may create a bug. Considering that the compiler should be able to
-    // optimize out the first comparison if day is an unsigned integer anyway,
-    // we will leave this comparison in place and disable the compiler warning.
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wtype-limits"
-    if (day < 0 || day > 6) {
-#pragma GCC diagnostic pop
+    // If the 'day' parameter type is changed to a signed type,
+    // "day < 0" check must be added.
+    if (/* day < 0 || */ day > 6) {
         PyErr_Format(PyExc_ValueError, "Day must be in [0, 6]");
         return -1;
     }