wip

Author: MarcoGorelli

pandas/_libs/tslibs/strptime.pyx

@@ -204,45 +204,38 @@ def array_strptime(
         else:
             val = str(val)
 
-        if (iso_format and not (fmt == "%Y%m%d" and len(val) != 8)):
-            # There is a fast-path for ISO8601-formatted strings.
-            # BUT for %Y%m%d, it only works if the string is 8-digits long.
+        if iso_format:
             string_to_dts_failed = string_to_dts(
                 val, &dts, &out_bestunit, &out_local,
                 &out_tzoffset, False, fmt, exact
             )
-            if string_to_dts_failed:
-                # An error at this point is a _parsing_ error
-                # specifically _not_ OutOfBoundsDatetime
-                if is_coerce:
-                    iresult[i] = NPY_NAT
-                    continue
-                raise ValueError(
-                    f"time data \"{val}\" at position {i} doesn't "
-                    f"match format \"{fmt}\""
-                )
-            # No error reported by string_to_dts, pick back up
-            # where we left off
-            value = npy_datetimestruct_to_datetime(NPY_FR_ns, &dts)
-            if out_local == 1:
-                # Store the out_tzoffset in seconds
-                # since we store the total_seconds of
-                # dateutil.tz.tzoffset objects
-                # out_tzoffset_vals.add(out_tzoffset * 60.)
-                tz = timezone(timedelta(minutes=out_tzoffset))
-                result_timezone[i] = tz
-                # value = tz_localize_to_utc_single(value, tz)
-                out_local = 0
-                out_tzoffset = 0
-            iresult[i] = value
-            try:
-                check_dts_bounds(&dts)
-            except ValueError:
-                if is_coerce:
-                    iresult[i] = NPY_NAT
-                    continue
-                raise
-            continue
+            if not string_to_dts_failed:
+                # No error reported by string_to_dts, pick back up
+                # where we left off
+                value = npy_datetimestruct_to_datetime(NPY_FR_ns, &dts)
+                if out_local == 1:
+                    # Store the out_tzoffset in seconds
+                    # since we store the total_seconds of
+                    # dateutil.tz.tzoffset objects
+                    # out_tzoffset_vals.add(out_tzoffset * 60.)
+                    tz = timezone(timedelta(minutes=out_tzoffset))
+                    result_timezone[i] = tz
+                    # value = tz_localize_to_utc_single(value, tz)
+                    out_local = 0
+                    out_tzoffset = 0
+                iresult[i] = value
+                try:
+                    check_dts_bounds(&dts)
+                except ValueError:
+                    if is_coerce:
+                        iresult[i] = NPY_NAT
+                        continue
+                    raise
+                continue
+
+        # Some ISO formats can't be parsed by string_to_dts
+        # For example, 6-digit YYYYMD. So, if there's an error,
+        # try the string-matching code below.
 
         # exact matching
         if exact: