Fix locale ISO datetime parsing

AUTHORS.txt

@@ -59,3 +59,4 @@ Pi R
 Alnoman Kamil - noman [at] kamil [dot] gr - https://kamil.gr
 Leonardo Taccari - iamleot [at] gmail [dot] com
 Jorenar - dev [at] jorenar [dot] com - https://jorenar.com
+Khanh Le

CHANGELOG.rst

@@ -11,6 +11,7 @@ may want to subscribe to `GitHub's tag feed
 ======
 unreleased
 * FIX add timezone when assigning start/end time
+* FIX parse ISO-like locale datetime formats with an empty timezone field
 
 0.14.0
 ======

khal/parse_datetime.py

@@ -23,6 +23,7 @@
 strings to date(time) or event objects"""
 
 import datetime as dt
+import locale
 import logging
 import re
 from calendar import isleap
@@ -39,6 +40,29 @@
 logger = logging.getLogger("khal")
 
 
+def _locale_format_candidates(dateformat: str) -> list[str]:
+    replacements = {
+        "%c": locale.D_T_FMT,
+        "%x": locale.D_FMT,
+        "%X": locale.T_FMT,
+    }
+    expanded_format = dateformat
+    for directive, nl_item in replacements.items():
+        if directive in expanded_format:
+            expanded_format = expanded_format.replace(directive, locale.nl_langinfo(nl_item))
+
+    candidates = [dateformat]
+    if expanded_format != dateformat:
+        candidates.append(expanded_format)
+
+    if "%Z" in expanded_format:
+        without_timezone = expanded_format.replace(" %Z", "").replace("%Z", "").strip()
+        if without_timezone not in candidates:
+            candidates.append(without_timezone)
+
+    return candidates
+
+
 def timefstr(dtime_list: list[str], timeformat: str) -> dt.datetime:
     """converts the first item of a list (a time as a string) to a datetimeobject
 
@@ -80,7 +104,15 @@ def datetimefstr(
     parts = dateformat.count(" ") + 1
     dtstring = " ".join(dtime_list[0:parts])
     # only time.strptime can parse the 29th of Feb. if no year is given
-    dtstart_struct = strptime(dtstring, dateformat)
+    for candidate_format in _locale_format_candidates(dateformat):
+        try:
+            dtstart_struct = strptime(dtstring, candidate_format)
+        except ValueError:
+            pass
+        else:
+            break
+    else:
+        raise ValueError
     if (
         infer_year
         and dtstart_struct.tm_mon == 2

tests/parse_datetime_test.py

@@ -1,4 +1,5 @@
 import datetime as dt
+import locale
 from collections import OrderedDict
 
 import pytest
@@ -206,6 +207,27 @@ def test_short_format_contains_year(self):
             "2017-1-1 16:30".split(), locale=locale, default_day=dt.datetime.today()
         )
 
+    def test_locale_datetime_with_empty_timezone(self, monkeypatch):
+        def nl_langinfo(item):
+            return {
+                locale.D_T_FMT: "%Y-%m-%dT%T %Z",
+                locale.D_FMT: "%Y-%m-%d",
+                locale.T_FMT: "%T",
+            }[item]
+
+        monkeypatch.setattr(locale, "nl_langinfo", nl_langinfo)
+        parsed = guessdatetimefstr(
+            ["2026-05-14T12:00:00"],
+            {
+                "timeformat": "%X",
+                "dateformat": "%x",
+                "longdateformat": "%x",
+                "datetimeformat": "%c",
+                "longdatetimeformat": "%c",
+            },
+        )
+        assert parsed == (dt.datetime(2026, 5, 14, 12), False)
+
 
 class TestGuessTimedeltafstr:
     def test_single(self):