feat: compatibility hints for sync, multiget and DELETE quirks

caldav/response.py

@@ -640,6 +640,11 @@ def _parse_response(self, response: _Element) -> tuple[str, list[_Element], Any
             ## 404s; flag it in debug mode if a server pairs them with some
             ## other status so we notice and revisit this handling.
             error.assert_("404" in status)
+        if status and " 404 " in status:
+            ## The resource is gone, so whatever its propstats say is moot.
+            ## Infomaniak adds an empty propstat with 418 to a removed member
+            ## of a sync-collection reply, which would otherwise raise.
+            propstats = []
         return (cast(str, href), propstats, status)
 
     def _parse_scheduling_response_objects(self, parent) -> dict:

changes/+sogo-rewrites.added.md

@@ -0,0 +1 @@
+Compatibility features `delete.if-match` (a DELETE with a stale If-Match is refused with 412; SOGo deletes the object anyway, while it refuses a stale If-Match on PUT), `save-load.event.floating` (an event with a floating DTSTART/DTEND is stored floating; SOGo pins it to TZID=Etc/UTC) and `save-load.icalendar.attendee-params` (ATTENDEE parameters are stored as sent; SOGo adds RSVP=TRUE, which changes the meaning, as the default is FALSE).  The SOGo profile has all three.

changes/+sync-404-propstats.fixed.md

@@ -0,0 +1 @@
+`Calendar.get_objects_by_sync_token()` no longer raises when a server answers a removed member with an extra propstat carrying an unexpected status: the propstats of a response whose own status is 404 are now ignored.  Infomaniak adds an empty propstat with "418 I'm a teapot" to every removed member.

changes/+sync-multiget-features.added.md

@@ -0,0 +1,8 @@
+Compatibility features for behaviours a sync client depends on, as found by calendaring-sync (https://github.com/PyCalendar/calendaring-sync/blob/c40782bc7afe7b350fe63bf27ef13374c280ea8b/docs/reference/server-compatibility.rst), each with a probe in caldav-server-tester:
+
+- `delete.missing` and `delete.missing.if-match`: a DELETE of a missing object answers 404, and one with If-Match answers as the plain one does (Baikal, Davis, Nextcloud, CCS, OX, Robur, Purelymail and Infomaniak answer 412 with it).
+- `save.etag.matches-stored`: a strong ETag in a PUT answer belongs to what was stored (Radicale, Xandikos, SOGo, CCS, Zimbra, Bedework 5 and Infomaniak rewrite the object and still answer with one).
+- `sync-token.initial-sync`, `sync-token.delete.created-and-deleted` and `sync-token.recreated`: which members a sync-collection report lists.
+- `multiget`, `multiget.missing-href` and `multiget.limit`, and `propfind.limit`: a calendar-multiget answers a missing href with a 404, and a multiget or a Depth: 1 PROPFIND answers every href (Stalwart stops at its maxResults, with a 507).
+
+The Stalwart test container now runs with a maxResults of 50 (`STALWART_MAX_RESULTS`), so the limit can be probed with few objects.

tests/docker-test-servers/stalwart/setup_stalwart.sh

@@ -159,6 +159,43 @@ create_user "user1" "caldavtest1"
 create_user "user2" "caldavtest2"
 create_user "user3" "caldavtest3"
 
+MAX_RESULTS="${STALWART_MAX_RESULTS:-50}"
+echo ""
+echo "Lowering WebDav.maxResults to ${MAX_RESULTS}..."
+# Stalwart caps PROPFIND, sync-collection and calendar-multiget answers at
+# WebDav.maxResults (2000 by default), with a 507 for the collection.  A low
+# cap lets caldav-server-tester see it with few objects
+# (CALDAV_SERVER_TESTER_LIMIT_OBJECTS).  The setting applies on a settings
+# reload, which refuses the image's default SpamDnsblServer entries
+# ("bit_and"); each entry it names is removed, in this container only.
+RESULT=$(jmap_call "{
+    \"using\": [\"urn:ietf:params:jmap:core\"],
+    \"methodCalls\": [[\"x:WebDav/set\", {
+        \"accountId\": \"d333333\",
+        \"update\": {\"singleton\": {\"maxResults\": ${MAX_RESULTS}}}
+    }, \"0\"]]
+}")
+if ! echo "$RESULT" | grep -q '"updated"'; then
+    echo "Warning: setting maxResults returned: $RESULT"
+fi
+for i in $(seq 1 40); do
+    RESULT=$(jmap_call '{"using":["urn:ietf:params:jmap:core"],"methodCalls":[["x:Action/set",{"accountId":"d333333","create":{"r":{"@type":"ReloadSettings"}}},"0"]]}')
+    if echo "$RESULT" | grep -q '"created"'; then
+        echo "maxResults is ${MAX_RESULTS}"
+        break
+    fi
+    BAD=$(echo "$RESULT" | python3 -c "import json,sys; b=json.load(sys.stdin)['methodResponses'][0][1]['notCreated']['r']['objectId']; print(b['object'], b['id'])" 2>/dev/null || true)
+    if [ -z "$BAD" ] || [ "$i" -eq 40 ]; then
+        echo "Warning: settings reload returned: $RESULT"
+        break
+    fi
+    read -r BAD_OBJECT BAD_ID <<< "$BAD"
+    jmap_call "{
+        \"using\": [\"urn:ietf:params:jmap:core\"],
+        \"methodCalls\": [[\"x:${BAD_OBJECT}/set\", {\"accountId\": \"d333333\", \"destroy\": [\"${BAD_ID}\"]}, \"0\"]]
+    }" > /dev/null
+done
+
 echo ""
 echo "Verifying CalDAV access..."
 # v0.16+: CalDAV path encodes the @ in the email address as %40.

tests/test_protocol.py

@@ -341,6 +341,36 @@ def test_parse_sync_collection_generic_error(self):
         assert result.deleted == ["/cal/gone.ics"]
         assert result.changed == []
 
+    ## Infomaniak (SabreDAV) answers a removed member with an empty propstat
+    ## carrying 418 next to the 404 of the response itself
+    removed_with_teapot_xml = b"""<?xml version="1.0"?>
+        <D:multistatus xmlns:D="DAV:">
+            <D:response>
+                <D:href>/cal/gone.ics</D:href>
+                <D:propstat>
+                    <D:prop/>
+                    <D:status>HTTP/1.1 418 I'm a teapot</D:status>
+                </D:propstat>
+                <D:status>HTTP/1.1 404 Not Found</D:status>
+            </D:response>
+            <D:sync-token>tok</D:sync-token>
+        </D:multistatus>"""
+
+    def test_parse_propfind_ignores_propstats_of_a_404(self):
+        results = DAVResponse.from_bytes(self.removed_with_teapot_xml).parse_propfind()
+
+        assert [(r.href, r.properties, r.status) for r in results] == [("/cal/gone.ics", {}, 404)]
+
+    def test_expand_simple_props_ignores_propstats_of_a_404(self):
+        """The legacy parser used by Calendar.get_objects_by_sync_token."""
+        from caldav.elements import dav
+
+        response = DAVResponse.from_bytes(self.removed_with_teapot_xml)
+        props = response.expand_simple_props([dav.GetEtag()])
+
+        assert props == {"/cal/gone.ics": {dav.GetEtag.tag: None}}
+        assert response.statuses == {"/cal/gone.ics": "HTTP/1.1 404 Not Found"}
+
     def test_parse_nested_properties(self):
         """Issue https://github.com/python-caldav/caldav/issues/795: properties
         nested deeper than one level gave the raw lxml element."""