Fix: free-busy REPORT always fails when max_freebusy_occurrence is 0

free_busy_report() explicitly handles [reporting] max_freebusy_occurrence = 0
as "limit disabled" when fetching occurrences (n=0 lets time_range_fill
return all occurrences), but the subsequent limit check
'len(occurrences) >= max_occurrence' is trivially true for
max_occurrence == 0, so every free-busy query on a non-empty calendar
raised ValueError ("FREEBUSY occurrences limit of 0 hit") and was
answered with HTTP 400.

Skip the limit check when the limit is disabled, consistent with how
xml_report() treats the same setting ('if max_occurrence and ...').
Behavior for positive limits is unchanged.

Co-Authored-By: Claude <noreply@anthropic.com>

radicale/app/report.py

@@ -133,7 +133,7 @@ def free_busy_report(base_prefix: str, path: str, xml_request: Optional[ET.Eleme
                                                       time_range_element,
                                                       "VEVENT",
                                                       n=n_occurrences)
-        if len(occurrences) >= max_occurrence:
+        if max_occurrence > 0 and len(occurrences) >= max_occurrence:
             raise ValueError("FREEBUSY occurrences limit of {} hit"
                              .format(max_occurrence))
 

radicale/tests/test_base.py

@@ -2232,6 +2232,18 @@ permissions: RrWw""")
     <C:time-range start="20130901T140000Z" end="20130908T220000Z"/>
 </C:free-busy-query>""", 400, is_xml=False)
 
+        # Test max_freebusy_occurrence set to 0 (limit disabled)
+        self.configure({"reporting": {"max_freebusy_occurrence": 0}})
+        code, responses = self.report(calendar_path, """\
+<?xml version="1.0" encoding="utf-8" ?>
+<C:free-busy-query xmlns:C="urn:ietf:params:xml:ns:caldav">
+    <C:time-range start="20130901T140000Z" end="20130908T220000Z"/>
+</C:free-busy-query>""", 200, is_xml=False)
+        assert len(responses) == 1
+        vcalendar = list(responses.values())[0]
+        assert isinstance(vcalendar, vobject.base.Component)
+        assert len(vcalendar.vfreebusy_list) == 3
+
     def _report_sync_token(
             self, calendar_path: str, sync_token: Optional[str] = None, **kwargs
             ) -> Tuple[str, RESPONSES]: