bpo-30155: Add macros to get tzinfo from datetime instances

Add PyDateTime_DATE_GET_TZINFO() and PyDateTime_TIME_GET_TZINFO() macros.
python · pganssle · Sep 23, 2020 · Jul 27, 2020 · Jul 28, 2020 · Sep 23, 2020
commit e018229fb7216e303ddcfbafa44b515791ace555
diff --git a/Doc/c-api/datetime.rst b/Doc/c-api/datetime.rst
@@ -185,6 +185,11 @@ must not be ``NULL``, and the type is not checked:

   Return the microsecond, as an int from 0 through 999999.

+.. c:function:: PyObject* PyDateTime_DATE_GET_TZINFO(PyDateTime_DateTime *o)
+
+   Return the tzinfo (which may be ``None``).
+
+   .. versionadded:: 3.10

 Macros to extract fields from time objects.  The argument must be an instance of
 :c:data:`PyDateTime_Time`, including subclasses. The argument must not be ``NULL``,
@@ -209,6 +214,12 @@ and the type is not checked:

   Return the microsecond, as an int from 0 through 999999.

+.. c:function:: PyObject* PyDateTime_TIME_GET_TZINFO(PyDateTime_Time *o)
+
+   Return the tzinfo (which may be ``None``).
+
+   .. versionadded:: 3.10
+

 Macros to extract fields from time delta objects.  The argument must be an
 instance of :c:data:`PyDateTime_Delta`, including subclasses. The argument must

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
@@ -231,6 +231,12 @@ New Features
  Python executable.
  (Contributed by Victor Stinner in :issue:`23427`.)

+* The :c:func:`PyDateTime_DATE_GET_TZINFO` and
+  :c:func:`PyDateTime_TIME_GET_TZINFO` macros have been added for accessing
+  the ``tzinfo`` attributes of :class:`datetime.datetime` and
+  :class:`datetime.time` objects.
+  (Contributed by Zackery Spytz in :issue:`30155`.)
+
 Porting to Python 3.10
 ----------------------


diff --git a/Include/datetime.h b/Include/datetime.h
@@ -115,6 +115,10 @@ typedef struct


 /* Apply for date and datetime instances. */
+
+// o is a pointer to a time or a datetime object.
+#define _PyDateTime_HAS_TZINFO(o)  (((_PyDateTime_BaseTZInfo *)(o))->hastzinfo)
+
 #define PyDateTime_GET_YEAR(o)     ((((PyDateTime_Date*)o)->data[0] << 8) | \
                     ((PyDateTime_Date*)o)->data[1])
 #define PyDateTime_GET_MONTH(o)    (((PyDateTime_Date*)o)->data[2])
@@ -128,6 +132,8 @@ typedef struct
     (((PyDateTime_DateTime*)o)->data[8] << 8)  |       \
      ((PyDateTime_DateTime*)o)->data[9])
 #define PyDateTime_DATE_GET_FOLD(o)        (((PyDateTime_DateTime*)o)->fold)
+#define PyDateTime_DATE_GET_TZINFO(o)      (_PyDateTime_HAS_TZINFO(o) ? \
+    ((PyDateTime_DateTime *)(o))->tzinfo : Py_None)

 /* Apply for time instances. */
 #define PyDateTime_TIME_GET_HOUR(o)        (((PyDateTime_Time*)o)->data[0])
@@ -138,6 +144,8 @@ typedef struct
     (((PyDateTime_Time*)o)->data[4] << 8)  |           \
      ((PyDateTime_Time*)o)->data[5])
 #define PyDateTime_TIME_GET_FOLD(o)        (((PyDateTime_Time*)o)->fold)
+#define PyDateTime_TIME_GET_TZINFO(o)      (_PyDateTime_HAS_TZINFO(o) ? \
+    ((PyDateTime_Time *)(o))->tzinfo : Py_None)

 /* Apply for time delta instances */
 #define PyDateTime_DELTA_GET_DAYS(o)         (((PyDateTime_Delta*)o)->days)

diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
@@ -5991,30 +5991,36 @@ class DateTimeSubclass(datetime):

        for klass in [datetime, DateTimeSubclass]:
            for args in [(1993, 8, 26, 22, 12, 55, 99999),
-                         (1993, 8, 26, 22, 12, 55, 99999)]:
+                         (1993, 8, 26, 22, 12, 55, 99999,
+                          FixedOffset(0, "UTC", -2))]:
                d = klass(*args)
                with self.subTest(cls=klass, date=args):
-                    hour, minute, second, microsecond = _testcapi.PyDateTime_DATE_GET(d)
+                    hour, minute, second, microsecond, tzinfo = \
+                                            _testcapi.PyDateTime_DATE_GET(d)

                    self.assertEqual(hour, d.hour)
                    self.assertEqual(minute, d.minute)
                    self.assertEqual(second, d.second)
                    self.assertEqual(microsecond, d.microsecond)
+                    self.assertEqual(tzinfo, d.tzinfo)

    def test_PyDateTime_TIME_GET(self):
        class TimeSubclass(time):
            pass

        for klass in [time, TimeSubclass]:
-            for args in [(12, 30, 20, 10), (12, 30, 20, 10)]:
+            for args in [(12, 30, 20, 10),
+                         (12, 30, 20, 10, FixedOffset(0, "UTC", -2))]:
                d = klass(*args)
                with self.subTest(cls=klass, date=args):
-                    hour, minute, second, microsecond = _testcapi.PyDateTime_TIME_GET(d)
+                    hour, minute, second, microsecond, tzinfo = \
+                                              _testcapi.PyDateTime_TIME_GET(d)

                    self.assertEqual(hour, d.hour)
                    self.assertEqual(minute, d.minute)
                    self.assertEqual(second, d.second)
                    self.assertEqual(microsecond, d.microsecond)
+                    self.assertEqual(tzinfo, d.tzinfo)

    def test_timezones_offset_zero(self):
        utc0, utc1, non_utc = _testcapi.get_timezones_offset_zero()

diff --git a/Misc/NEWS.d/next/C API/2020-07-26-19-39-45.bpo-30155.rHZRJ_.rst b/Misc/NEWS.d/next/C API/2020-07-26-19-39-45.bpo-30155.rHZRJ_.rst
@@ -0,0 +1,3 @@
+Add :c:func:`PyDateTime_DATE_GET_TZINFO` and
+:c:func:`PyDateTime_TIME_GET_TZINFO` macros for accessing the ``tzinfo``
+attributes of :class:`datetime.datetime` and :class:`datetime.time` objects.
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
@@ -115,14 +115,9 @@ class datetime.IsoCalendarDate "PyDateTime_IsoCalendarDate *" "&PyDateTime_IsoCa
 #define SET_TD_SECONDS(o, v)    ((o)->seconds = (v))
 #define SET_TD_MICROSECONDS(o, v) ((o)->microseconds = (v))

-/* p is a pointer to a time or a datetime object; HASTZINFO(p) returns
- * p->hastzinfo.
- */
-#define HASTZINFO(p) (((_PyDateTime_BaseTZInfo *)(p))->hastzinfo)
-#define GET_TIME_TZINFO(p) (HASTZINFO(p) ? \
-                            ((PyDateTime_Time *)(p))->tzinfo : Py_None)
-#define GET_DT_TZINFO(p) (HASTZINFO(p) ? \
-                          ((PyDateTime_DateTime *)(p))->tzinfo : Py_None)
+#define HASTZINFO               _PyDateTime_HAS_TZINFO
+#define GET_TIME_TZINFO         PyDateTime_TIME_GET_TZINFO
+#define GET_DT_TZINFO           PyDateTime_DATE_GET_TZINFO
 /* M is a char or int claiming to be a valid month.  The macro is equivalent
 * to the two-sided Python test
 *      1 <= M <= 12

diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
@@ -2677,8 +2677,9 @@ test_PyDateTime_DATE_GET(PyObject *self, PyObject *obj)
    minute = PyDateTime_DATE_GET_MINUTE(obj);
    second = PyDateTime_DATE_GET_SECOND(obj);
    microsecond = PyDateTime_DATE_GET_MICROSECOND(obj);
+    PyObject *tzinfo = PyDateTime_DATE_GET_TZINFO(obj);

-    return Py_BuildValue("(llll)", hour, minute, second, microsecond);
+    return Py_BuildValue("(llllO)", hour, minute, second, microsecond, tzinfo);
 }

 static PyObject *
@@ -2690,8 +2691,9 @@ test_PyDateTime_TIME_GET(PyObject *self, PyObject *obj)
    minute = PyDateTime_TIME_GET_MINUTE(obj);
    second = PyDateTime_TIME_GET_SECOND(obj);
    microsecond = PyDateTime_TIME_GET_MICROSECOND(obj);
+    PyObject *tzinfo = PyDateTime_TIME_GET_TZINFO(obj);

-    return Py_BuildValue("(llll)", hour, minute, second, microsecond);
+    return Py_BuildValue("(llllO)", hour, minute, second, microsecond, tzinfo);
 }

 static PyObject *

diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
@@ -484,9 +484,7 @@ zoneinfo_tzname(PyObject *self, PyObject *dt)
    return tti->tzname;
 }

-#define HASTZINFO(p) (((_PyDateTime_BaseTZInfo *)(p))->hastzinfo)
-#define GET_DT_TZINFO(p) \
-    (HASTZINFO(p) ? ((PyDateTime_DateTime *)(p))->tzinfo : Py_None)
+#define GET_DT_TZINFO PyDateTime_DATE_GET_TZINFO

 static PyObject *
 zoneinfo_fromutc(PyObject *obj_self, PyObject *dt)
-Original file line number
+Diff line change
@@ -484,9 +484,7 @@ zoneinfo_tzname(PyObject *self, PyObject *dt)
         return tti->tzname;
     }
-    #define HASTZINFO(p) (((_PyDateTime_BaseTZInfo *)(p))->hastzinfo)
-    #define GET_DT_TZINFO(p) \
-        (HASTZINFO(p) ? ((PyDateTime_DateTime *)(p))->tzinfo : Py_None)
+    #define GET_DT_TZINFO PyDateTime_DATE_GET_TZINFO
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            pganssle
  

      

      

      


        Jul 27, 2020


      
    

  


        
      
  
  
  
    

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      Alternatively we can replace all the instances of GET_DT_TZINFO with PyDateTime_DATE_GET_TZINFO. I think either way works, because in the backport I'm either going to do:
#ifdef PyDateTime_DATE_GET_TZINFO
#define GET_DT_TZINFO PyDateTime_DATE_GET_TZINFO
#else
#define HASTZINFO ...

or I'll do this:
#ifndef PyDateTime_DATE_GET_TZINFO
#define _PyDateTime_HAS_TZINFO ...
#define PyDateTime_DATE_GET_TZINFO (_PyDateTime_HAS_TZINFO(p) ? ...

Then the rest of the file will be the same.
I was originally liking the first one, but upon further reflection, I like the second one. What do you think? (It's also OK to say that you like the second one more but you want to keep it out of scope of this PR).
    
  
  


    

        
      
  
  
    
  
  
  
    
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            ZackerySpytz
  

      

      

      


        Jul 29, 2020


      
    

  


        
      
  
  
  
    

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      I like the second one more, but I think it is out of scope for this PR. :)
    
  
  


    

        
      
  
  
    
  
  
  
    
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     static PyObject *
     zoneinfo_fromutc(PyObject *obj_self, PyObject *dt)
-          Expand Down