feat: add RFC6638 scheduling feature support and test infrastructure

Add scheduling support to FeatureSet compatibility hints:
- New 'scheduling' feature and sub-features (scheduling.mailbox,
  scheduling.calendar-user-address-set)
- Migrate legacy no_scheduling old flags to the new feature system
- Add scheduling_users defaults for Nextcloud, DAViCal, and Zimbra

Add RFC6638 scheduling test infrastructure:
- Enable multi-user scheduling tests via docker server setups
- Pre-populate scheduling_users in Cyrus and Baikal server classes
- Fix test collection and server config merging for scheduling_users

Author: tobixen

.github/workflows/tests.yaml

@@ -149,6 +149,11 @@ jobs:
           # Create test user
           docker exec -e OC_PASS="testpass" ${{ job.services.nextcloud.id }} php occ user:add --password-from-env --display-name="Test User" testuser || echo "User may already exist"
 
+          # Create scheduling test users (user1-user3)
+          for i in 1 2 3; do
+            docker exec -e OC_PASS="testpass${i}" ${{ job.services.nextcloud.id }} php occ user:add --password-from-env --display-name="User ${i}" "user${i}" || echo "user${i} may already exist"
+          done
+
           # Enable calendar and contacts apps
           docker exec ${{ job.services.nextcloud.id }} php occ app:enable calendar || true
           docker exec ${{ job.services.nextcloud.id }} php occ app:enable contacts || true

caldav/compatibility_hints.py

@@ -264,6 +264,18 @@ class FeatureSet:
         "sync-token.delete": {
             "description": "Server correctly handles sync-collection reports after objects have been deleted from the calendar (solved in Nextcloud in https://github.com/nextcloud/server/pull/44130)"
         },
+        "scheduling": {
+            "description": "Server supports CalDAV Scheduling (RFC6638). Detected via the presence of 'calendar-auto-schedule' in the DAV response header.",
+            "links": ["https://datatracker.ietf.org/doc/html/rfc6638"],
+        },
+        "scheduling.mailbox": {
+            "description": "Server provides schedule-inbox and schedule-outbox collections for the principal (RFC6638 sections 2.2-2.3). When unsupported, calls to schedule_inbox() or schedule_outbox() raise NotFoundError.",
+            "links": ["https://datatracker.ietf.org/doc/html/rfc6638#section-2.2"],
+        },
+        "scheduling.calendar-user-address-set": {
+            "description": "Server provides the calendar-user-address-set property on the principal (RFC6638 section 2.4.1), used to identify a user's email/URI for scheduling purposes. When unsupported, calendar_user_address_set() raises NotFoundError.",
+            "links": ["https://datatracker.ietf.org/doc/html/rfc6638#section-2.4.1"],
+        },
         'freebusy-query': {'description': "freebusy queries come in two flavors, one query can be done towards a CalDAV server as defined in RFC4791, another query can be done through the scheduling framework, RFC 6638.  Only RFC4791 is tested for as today"},
         "freebusy-query.rfc4791": {
             "description": "Server supports free/busy-query REPORT as specified in RFC4791 section 7.10. The REPORT allows clients to query for free/busy time information for a time range. Servers without this support will typically return an error (often 500 Internal Server Error or 501 Not Implemented). Note: RFC6638 defines a different freebusy mechanism for scheduling",
@@ -710,15 +722,6 @@ def dotted_feature_set_list(self, compact=False):
 ## * Perhaps some more readable format should be considered (yaml?).
 ## * Consider how to get this into the documentation
 incompatibility_description = {
-    'no_scheduling':
-        """RFC6833 is not supported""",
-
-    'no_scheduling_mailbox':
-        """Parts of RFC6833 is supported, but not the existence of inbox/mailbox""",
-
-    'no_scheduling_calendar_user_address_set':
-        """Parts of RFC6833 is supported, but not getting the calendar users addresses""",
-
     'no_default_calendar':
         """The given user starts without an assigned default calendar """
         """(or without pre-defined calendars at all)""",
@@ -837,14 +840,12 @@ def dotted_feature_set_list(self, compact=False):
     "search.text.category.substring": {"support": "unsupported"},
     'principal-search': {'support': 'unsupported'},
     'freebusy-query.rfc4791': {'support': 'ungraceful', 'behaviour': '500 internal server error'},
+    "scheduling": {"support": "unsupported"},
     "old_flags":  [
     ## https://github.com/jelmer/xandikos/issues/8
     'date_todo_search_ignores_duration',
     'vtodo_datesearch_nostart_future_tasks_delivered',
 
-    ## scheduling is not supported
-    "no_scheduling",
-
     ## The test with an rrule and an overridden event passes as
     ## long as it's with timestamps.  With dates, xandikos gets
     ## into troubles.  I've chosen to edit the test to use timestamp
@@ -872,13 +873,11 @@ def dotted_feature_set_list(self, compact=False):
     ## this only applies for very simple installations
     "auto-connect.url": {"domain": "localhost", "scheme": "http", "basepath": "/"},
 
+    "scheduling": {"support": "unsupported"},
     "old_flags":  [
     ## https://github.com/jelmer/xandikos/issues/8
     'date_todo_search_ignores_duration',
     'vtodo_datesearch_nostart_future_tasks_delivered',
-
-    ## scheduling is not supported
-    "no_scheduling",
     ]
 }
 
@@ -895,11 +894,11 @@ def dotted_feature_set_list(self, compact=False):
     ## this only applies for very simple installations
     "auto-connect.url": {"domain": "localhost", "scheme": "http", "basepath": "/"},
     ## freebusy is not supported yet, but on the long-term road map
+    "scheduling": {"support": "unsupported"},
     'old_flags': [
     ## calendar listings and calendar creation works a bit
     ## "weird" on radicale
 
-    'no_scheduling',
     'no_search_openended',
 
     #'text_search_is_exact_match_sometimes',
@@ -1224,9 +1223,10 @@ def dotted_feature_set_list(self, compact=False):
     'search.recurrences.includes-implicit.todo': {'support': 'unsupported'},
     'principal-search': {'support': 'ungraceful'},
     'freebusy-query.rfc4791': {'support': 'ungraceful'},
+    "scheduling": {"support": "unsupported"},
     'old_flags': [
         'non_existing_raises_other', ## AuthorizationError instead of NotFoundError
-        'no_scheduling',
+        'no_supported_components_support',
         'no_relships',
     ],
     'test-calendar': {'cleanup-regime': 'wipe-calendar'},
@@ -1266,8 +1266,8 @@ def dotted_feature_set_list(self, compact=False):
     'search.combined-is-logical-and': {'support': 'unsupported'},
     'sync-token': {'support': 'ungraceful'},
     'principal-search': {'support': 'unsupported'},
+    "scheduling": {"support": "unsupported"},
     'old_flags': [
-        'no_scheduling',
         #'no_recurring_todo', ## todo
     ]
 }
@@ -1401,9 +1401,10 @@ def dotted_feature_set_list(self, compact=False):
         'basepath': '/webdav/',
         'domain': 'purelymail.com',
     },
+    ## Known, work in progress
+    "scheduling": {"support": "unsupported"},
     'old_flags': [
-        ## Known, work in progress
-        'no_scheduling',
+        'no_supported_components_support',
     ],
     ## Known, not a breach of standard
     "get-supported-components": {"support": "unsupported"},
@@ -1445,11 +1446,14 @@ def dotted_feature_set_list(self, compact=False):
     ## was apparently observed working for a while, possibly due to the master/more_checks split-brain git branching incident in the server-checker project.
     ## unsupported in be26d42b1ca3ff3b4fd183761b4a9b024ce12b84 / 537a23b145487006bb987dee5ab9e00cdebb0492 2026-02-19.  Supported when testing again short time after.  Either I'm confused or it's "fragile".
     #'search.time-range.alarm': {'support': 'unsupported'},
+    ## GMX advertises calendar-auto-schedule but inbox/mailbox and
+    ## calendar-user-address-set are not functional (RFC6638 sub-features).
+    "scheduling": {"support": "full"},
+    "scheduling.mailbox": {"support": "unsupported"},
+    "scheduling.calendar-user-address-set": {"support": "unsupported"},
     "old_flags":  [
-        "no_scheduling_mailbox",
         #"text_search_is_case_insensitive",
         "no_search_openended",
-        "no_scheduling_calendar_user_address_set",
         "vtodo-cannot-be-uncompleted",
     ]
 }

tests/caldav_test_servers.yaml.example

@@ -52,6 +52,7 @@ test-servers:
     port: ${NEXTCLOUD_PORT:-8801}
     username: ${NEXTCLOUD_USERNAME:-testuser}
     password: ${NEXTCLOUD_PASSWORD:-testpass}
+    # setup_nextcloud.sh creates user1-user3 (passwords testpass1-3) for scheduling tests.
 
   cyrus:
     type: docker
@@ -60,6 +61,17 @@ test-servers:
     port: ${CYRUS_PORT:-8802}
     username: ${CYRUS_USERNAME:-testuser@test.local}
     password: ${CYRUS_PASSWORD:-testpassword}
+    # Cyrus pre-creates user1-user5 (password 'x'), enabling scheduling tests.
+    scheduling_users:
+      - url: http://${CYRUS_HOST:-localhost}:${CYRUS_PORT:-8802}/dav/calendars/user/user1
+        username: user1@test.local
+        password: x
+      - url: http://${CYRUS_HOST:-localhost}:${CYRUS_PORT:-8802}/dav/calendars/user/user2
+        username: user2@test.local
+        password: x
+      - url: http://${CYRUS_HOST:-localhost}:${CYRUS_PORT:-8802}/dav/calendars/user/user3
+        username: user3@test.local
+        password: x
 
   sogo:
     type: docker
@@ -84,6 +96,7 @@ test-servers:
     port: ${DAVICAL_PORT:-8805}
     username: ${DAVICAL_USERNAME:-testuser}
     password: ${DAVICAL_PASSWORD:-testpass}
+    # setup_davical.sh creates user1-user3 (passwords testpass1-3) for scheduling tests.
 
   davis:
     type: docker
@@ -108,6 +121,7 @@ test-servers:
     port: ${ZIMBRA_PORT:-8808}
     username: ${ZIMBRA_USERNAME:-testuser@zimbra.io}
     password: ${ZIMBRA_PASSWORD:-testpass}
+    # start.sh creates testuser/testuser2/testuser3@zimbra.io (password testpass) for scheduling tests.
 
   stalwart:
     type: docker
@@ -150,13 +164,49 @@ test-servers:
 # RFC6638 scheduling test users (optional)
 # =========================================================================
 #
-# For testing calendar scheduling (meeting invites, etc.), define
-# multiple users that can send invites to each other:
-
+# Preferred: add scheduling_users inside a server block (as shown for Cyrus
+# above).  The registry merges it into the already-registered server, and
+# pytest generates a TestSchedulingForServer<Name> class automatically.
+#
+# Baikal (user1-user3 in pre-seeded db.sqlite, passwords testpass1-3):
+#
+#   baikal:
+#     scheduling_users:
+#       - url: http://localhost:8800/dav.php/
+#         username: user1
+#         password: testpass1
+#       - url: http://localhost:8800/dav.php/
+#         username: user2
+#         password: testpass2
+#       - url: http://localhost:8800/dav.php/
+#         username: user3
+#         password: testpass3
+#
+# SOGo (user1-user3 from init-sogo-users.sql, passwords testpass1-3):
+#
+#   sogo:
+#     scheduling_users:
+#       - url: http://localhost:8803/SOGo/dav/user1
+#         username: user1
+#         password: testpass1
+#       - url: http://localhost:8803/SOGo/dav/user2
+#         username: user2
+#         password: testpass2
+#       - url: http://localhost:8803/SOGo/dav/user3
+#         username: user3
+#         password: testpass3
+#
+# Legacy: top-level rfc6638_users creates a single TestScheduling class
+# that is not tied to any specific server in the test run.  Prefer the
+# per-server scheduling_users approach above.
+#
 # rfc6638_users:
-#   - url: https://caldav.example.com/dav/user1/
+#   - url: http://localhost:8802/dav/calendars/user/user1
 #     username: user1
-#     password: pass1
-#   - url: https://caldav.example.com/dav/user2/
+#     password: x
+#   - url: http://localhost:8802/dav/calendars/user/user2
 #     username: user2
-#     password: pass2
+#     password: x
+#   - url: http://localhost:8802/dav/calendars/user/user3
+#     username: user3
+#     password: x

tests/docker-test-servers/baikal/Specific/db/db.sqlite

@@ -232,6 +232,47 @@ def create_baikal_db(db_path: Path, username: str = "testuser", password: str =
     print(f"  Digest A1: {ha1}")
 
 
+def add_baikal_user(db_path: Path, username: str, password: str) -> None:
+    """Add an additional user to an existing Baikal SQLite database."""
+    realm = "BaikalDAV"
+    ha1 = hashlib.md5(f"{username}:{realm}:{password}".encode()).hexdigest()
+    principal_uri = f"principals/{username}"
+
+    conn = sqlite3.connect(str(db_path))
+    cursor = conn.cursor()
+
+    cursor.execute("INSERT OR REPLACE INTO users (username, digesta1) VALUES (?, ?)", (username, ha1))
+
+    cursor.execute(
+        "INSERT OR IGNORE INTO principals (uri, email, displayname) VALUES (?, ?, ?)",
+        (principal_uri, f"{username}@baikal.test", f"Test User ({username})"),
+    )
+
+    cursor.execute(
+        "INSERT INTO calendars (synctoken, components) VALUES (?, ?)",
+        (1, "VEVENT,VTODO,VJOURNAL"),
+    )
+    calendar_id = cursor.lastrowid
+
+    cursor.execute(
+        """INSERT INTO calendarinstances
+           (calendarid, principaluri, access, displayname, uri, calendarorder, calendarcolor)
+           VALUES (?, ?, ?, ?, ?, ?, ?)""",
+        (calendar_id, principal_uri, 1, "Default Calendar", "default", 0, "#3a87ad"),
+    )
+
+    cursor.execute(
+        """INSERT INTO addressbooks
+           (principaluri, displayname, uri, synctoken)
+           VALUES (?, ?, ?, ?)""",
+        (principal_uri, "Default Address Book", "default", 1),
+    )
+
+    conn.commit()
+    conn.close()
+    print(f"✓ Added user '{username}' to Baikal database")
+
+
 def create_baikal_config(config_path: Path) -> None:
     """Create Baikal config.php file."""
 
@@ -358,10 +399,14 @@ def create_baikal_yaml(yaml_path: Path) -> None:
 if __name__ == "__main__":
     script_dir = Path(__file__).parent
 
-    # Create database
+    # Create database with primary test user
     db_path = script_dir / "Specific" / "db" / "db.sqlite"
     create_baikal_db(db_path, username="testuser", password="testpass")
 
+    # Add extra users for RFC6638 scheduling tests (need at least 3)
+    for i in range(1, 4):
+        add_baikal_user(db_path, username=f"user{i}", password=f"testpass{i}")
+
     # Create legacy PHP config files (for older Baikal versions)
     config_path = script_dir / "Specific" / "config.php"
     create_baikal_config(config_path)
@@ -380,4 +425,5 @@ def create_baikal_yaml(yaml_path: Path) -> None:
     print("\nCredentials:")
     print("  Admin: admin / admin")
     print("  User: testuser / testpass")
+    print("  RFC6638 users: user1/testpass1, user2/testpass2, user3/testpass3")
     print("  CalDAV URL: http://localhost:8800/dav.php/")

tests/docker-test-servers/baikal/create_baikal_db.py

@@ -34,25 +34,32 @@ for i in $(seq 1 $max_attempts); do
     sleep 3
 done
 
-echo ""
-echo "Creating test user..."
-# Check if user already exists
-EXISTING=$(run_sql "SELECT username FROM usr WHERE username='${TEST_USER}'")
-if [ -n "$EXISTING" ]; then
-    echo "User '${TEST_USER}' already exists, skipping creation"
-else
-    run_sql "INSERT INTO usr (username, password, fullname, email) VALUES ('${TEST_USER}', '**${TEST_PASSWORD}', 'Test User', '${TEST_USER}@example.com')"
-    echo "User created"
-fi
+create_user() {
+    local username="$1"
+    local password="$2"
+    local fullname="$3"
+    EXISTING=$(run_sql "SELECT username FROM usr WHERE username='${username}'")
+    if [ -n "$EXISTING" ]; then
+        echo "User '${username}' already exists, skipping creation"
+    else
+        run_sql "INSERT INTO usr (username, password, fullname, email) VALUES ('${username}', '**${password}', '${fullname}', '${username}@example.com')"
+        echo "User '${username}' created"
+    fi
+    EXISTING_PRINCIPAL=$(run_sql "SELECT principal_id FROM principal p JOIN usr u ON p.user_no = u.user_no WHERE u.username='${username}'")
+    if [ -n "$EXISTING_PRINCIPAL" ]; then
+        echo "Principal for '${username}' already exists, skipping"
+    else
+        run_sql "INSERT INTO principal (type_id, user_no, displayname) SELECT 1, user_no, fullname FROM usr WHERE username='${username}'"
+        echo "Principal for '${username}' created"
+    fi
+}
 
-echo "Creating principal entry..."
-EXISTING_PRINCIPAL=$(run_sql "SELECT principal_id FROM principal p JOIN usr u ON p.user_no = u.user_no WHERE u.username='${TEST_USER}'")
-if [ -n "$EXISTING_PRINCIPAL" ]; then
-    echo "Principal already exists, skipping"
-else
-    run_sql "INSERT INTO principal (type_id, user_no, displayname) SELECT 1, user_no, fullname FROM usr WHERE username='${TEST_USER}'"
-    echo "Principal created"
-fi
+echo ""
+echo "Creating test users..."
+create_user "${TEST_USER}" "${TEST_PASSWORD}" "Test User"
+create_user "user1" "testpass1" "User One"
+create_user "user2" "testpass2" "User Two"
+create_user "user3" "testpass3" "User Three"
 
 echo ""
 echo "Verifying CalDAV access..."
@@ -79,4 +86,5 @@ echo ""
 echo "Credentials:"
 echo "  Admin: admin / testpass"
 echo "  Test user: ${TEST_USER} / ${TEST_PASSWORD}"
+echo "  Scheduling users: user1/testpass1, user2/testpass2, user3/testpass3"
 echo "  CalDAV URL: http://localhost:8805/caldav.php/${TEST_USER}/"

tests/docker-test-servers/davical/setup_davical.sh

@@ -27,9 +27,13 @@ echo ""
 echo "Disabling password policy for testing..."
 docker exec $CONTAINER_NAME php occ app:disable password_policy || true
 
-echo "Creating test user..."
+echo "Creating test users..."
 # Create test user (ignore error if already exists)
 docker exec -e OC_PASS="$TEST_PASSWORD" $CONTAINER_NAME php occ user:add --password-from-env --display-name="Test User" $TEST_USER 2>/dev/null || echo "User may already exist"
+# Create scheduling test users
+for i in 1 2 3; do
+    docker exec -e OC_PASS="testpass${i}" $CONTAINER_NAME php occ user:add --password-from-env --display-name="User ${i}" "user${i}" 2>/dev/null || echo "user${i} may already exist"
+done
 
 echo "Enabling calendar app..."
 docker exec $CONTAINER_NAME php occ app:enable calendar || true
@@ -64,5 +68,6 @@ echo ""
 echo "Credentials:"
 echo "  Admin: admin / admin"
 echo "  Test user: $TEST_USER / $TEST_PASSWORD"
+echo "  Scheduling users: user1/testpass1, user2/testpass2, user3/testpass3"
 echo "  CalDAV URL: http://localhost:8801/remote.php/dav"
 echo ""