From 8bcd43742aa561d3d57131db3a4f302f6593f16d Mon Sep 17 00:00:00 2001
From: Peter Bieringer <pb@bieringer.de>
Date: Sun, 21 Jun 2026 16:30:53 +0200
Subject: [PATCH] add test whether vobject supports PERIOD

---
 radicale/item/__init__.py | 21 +++++++++++++++++++++
 radicale/utils.py         | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/radicale/item/__init__.py b/radicale/item/__init__.py
index 17ef72fb..17cb66fb 100644
--- a/radicale/item/__init__.py
+++ b/radicale/item/__init__.py
@@ -200,6 +200,27 @@ def check_and_sanitize_items(
                                     logger.trace("ITEM/check_and_sanitize_item: remove existing tzinfo (dtstart has none): '%s' -> '%s'", date, dates.value[i])
                     if all(type(d) is type(ref_date) for d in dates.value):
                         continue
+                    if dates.params.get("VALUE") == ["PERIOD"]:
+                        if not utils.vobject_supports_period():
+                            raise ValueError("PERIOD not supported by used vobject=%s in object %r" % (utils.package_version("vobject"), component_uid))
+                        # period     = period-explicit / period-start
+                        # period-explicit = date-time "/" date-time
+                        # period-start = date-time "/" dur-value
+                        for i, date in enumerate(dates.value):
+                            if not isinstance(date, tuple):
+                                raise ValueError("invalid PERIOD (not a tuple) in object %r" % component_uid)
+                            if len(date) != 2:
+                                raise ValueError("invalid PERIOD (not 2 elements) in object %r" % component_uid)
+                            if type(date[0]) is datetime.datetime and type(date[1]) is datetime.datetime:
+                                if (date[0] > date[1]):
+                                    raise ValueError("invalid PERIOD (end before start) in object %r" % component_uid)
+                                # skip explicit tzinfo check for now, no buggy client known
+                                logger.trace("ITEM/check_and_sanitize_item: PERIOD/start-stop found: '%s'", date)
+                            elif type(date[0]) is datetime.datetime and type(date[1]) is datetime.timedelta:
+                                logger.trace("ITEM/check_and_sanitize_item: PERIOD/start-duration found: '%s'", date)
+                            else:
+                                raise ValueError("invalid PERIOD (element types not matching) in object %r" % component_uid)
+                        continue
                     for i, date in enumerate(dates.value):
                         dates.value[i] = ref_date.replace(
                             date.year, date.month, date.day)
diff --git a/radicale/utils.py b/radicale/utils.py
index eba1fa30..dbf8b8eb 100644
--- a/radicale/utils.py
+++ b/radicale/utils.py
@@ -27,6 +27,8 @@ from importlib import import_module, metadata
 from string import ascii_letters, digits, punctuation
 from typing import Callable, Sequence, Tuple, Type, TypeVar, Union
 
+import vobject
+
 from radicale import config
 from radicale.log import logger
 
@@ -107,6 +109,43 @@ def vobject_supports_vcard4() -> bool:
         return False
 
 
+# global cache
+vobject_supports_period_cache: Union[bool, None] = None
+
+
+def vobject_supports_period() -> bool:
+    """Check if vobject supports period (requires version > 0.9.9)."""
+    global vobject_supports_period_cache
+
+    if vobject_supports_period_cache is not None:
+        return vobject_supports_period_cache
+
+    content_test = """
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:test
+BEGIN:VEVENT
+UID:test-rdate-period-time-start-stop
+DTSTART:20000101T000000Z
+DURATION:PT1H
+DESCRIPTION:event with rdate period start and stop
+DTSTAMP:20000101T000000Z
+RDATE;VALUE=PERIOD:20000102T000000Z/20000402T000000Z
+RRULE:FREQ=WEEKLY
+END:VEVENT
+END:VCALENDAR
+"""
+    obj = vobject.readOne(content_test)
+
+    try:
+        obj.serialize()
+    except Exception:
+        vobject_supports_period_cache = False
+    else:
+        vobject_supports_period_cache = True
+    return vobject_supports_period_cache
+
+
 def packages_version():
     versions = []
     versions.append("python=%s.%s.%s" % (sys.version_info[0], sys.version_info[1], sys.version_info[2]))