BUG: time is lost from datetime.datetime when converting to datetime64 (#11149)

datetime.datetime is a subclass of datetime.date, so it needs to be checked against first

Fixes #11106

2 files changed, 18 insertions, 11 deletions

diff --git a/numpy/core/src/multiarray/datetime.c b/numpy/core/src/multiarray/datetime.c
index a4a028ad4..b026e5fae 100644
--- a/numpy/core/src/multiarray/datetime.c
+++ b/numpy/core/src/multiarray/datetime.c
@@ -3679,11 +3679,11 @@ recursive_find_object_datetime64_type(PyObject *obj,
 
         return 0;
     }
-    /* Python date object -> 'D' */
-    else if (PyDate_Check(obj)) {
+    /* Python datetime object -> 'us' */
+    else if (PyDateTime_Check(obj)) {
         PyArray_DatetimeMetaData tmp_meta;
 
-        tmp_meta.base = NPY_FR_D;
+        tmp_meta.base = NPY_FR_us;
         tmp_meta.num = 1;
 
         /* Combine it with 'meta' */
@@ -3694,11 +3694,11 @@ recursive_find_object_datetime64_type(PyObject *obj,
 
         return 0;
     }
-    /* Python datetime object -> 'us' */
-    else if (PyDateTime_Check(obj)) {
+    /* Python date object -> 'D' */
+    else if (PyDate_Check(obj)) {
         PyArray_DatetimeMetaData tmp_meta;
 
-        tmp_meta.base = NPY_FR_us;
+        tmp_meta.base = NPY_FR_D;
         tmp_meta.num = 1;
 
         /* Combine it with 'meta' */
diff --git a/numpy/core/tests/test_datetime.py b/numpy/core/tests/test_datetime.py
index dca2d2541..43e8a3325 100644
--- a/numpy/core/tests/test_datetime.py
+++ b/numpy/core/tests/test_datetime.py
@@ -236,18 +236,25 @@ class TestDateTime(object):
         # find "supertype" for non-dates and dates
 
         b = np.bool_(True)
-        dt = np.datetime64('1970-01-01', 'M')
-        arr = np.array([b, dt])
+        dm = np.datetime64('1970-01-01', 'M')
+        d = datetime.date(1970, 1, 1)
+        dt = datetime.datetime(1970, 1, 1, 12, 30, 40)
+
+        arr = np.array([b, dm])
         assert_equal(arr.dtype, np.dtype('O'))
 
-        dt = datetime.date(1970, 1, 1)
-        arr = np.array([b, dt])
+        arr = np.array([b, d])
         assert_equal(arr.dtype, np.dtype('O'))
 
-        dt = datetime.datetime(1970, 1, 1, 12, 30, 40)
         arr = np.array([b, dt])
         assert_equal(arr.dtype, np.dtype('O'))
 
+        arr = np.array([d, d]).astype('datetime64')
+        assert_equal(arr.dtype, np.dtype('M8[D]'))
+
+        arr = np.array([dt, dt]).astype('datetime64')
+        assert_equal(arr.dtype, np.dtype('M8[us]'))
+
     def test_timedelta_scalar_construction(self):
         # Construct with different units
         assert_equal(np.timedelta64(7, 'D'),