export: Add missing datetime fields for post-processing.

datetime objects are not ordinarily JSON serializable.  While both
ujson and orjson have special cases to serialize datetime objects,
they do it in different ways.  So we want to fix the post-processing
code to do its job.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/lib/export.py

@@ -279,6 +279,7 @@ ANALYTICS_TABLES = {
 # TODO: This data structure could likely eventually be replaced by
 # inspecting the corresponding Django models
 DATE_FIELDS: Dict[TableName, List[Field]] = {
+    'zerver_analytics': ['date_created'],
     'zerver_attachment': ['create_time'],
     'zerver_message': ['last_edit_time', 'date_sent'],
     'zerver_mutedtopic': ['date_muted'],
@@ -288,6 +289,7 @@ DATE_FIELDS: Dict[TableName, List[Field]] = {
     'zerver_useractivityinterval': ['start', 'end'],
     'zerver_userpresence': ['timestamp'],
     'zerver_userprofile': ['date_joined', 'last_login', 'last_reminder'],
+    'zerver_userprofile_mirrordummy': ['date_joined', 'last_login', 'last_reminder'],
     'zerver_realmauditlog': ['event_time'],
     'zerver_userhotspot': ['timestamp'],
     'analytics_installationcount': ['end_time'],
@@ -469,14 +471,13 @@ def export_from_config(response: TableData, config: Config, seed_object: Optiona
     if context is None:
         context = {}
 
-    if table:
-        exported_tables = [table]
-    else:
-        if config.custom_tables is None:
-            raise AssertionError('''
-                You must specify config.custom_tables if you
-                are not specifying config.table''')
+    if config.custom_tables:
         exported_tables = config.custom_tables
+    else:
+        assert table is not None, '''
+            You must specify config.custom_tables if you
+            are not specifying config.table'''
+        exported_tables = [table]
 
     for t in exported_tables:
         logging.info('Exporting via export_from_config:  %s', t)
@@ -548,12 +549,14 @@ def export_from_config(response: TableData, config: Config, seed_object: Optiona
         query = model.objects.filter(**filter_parms)
         rows = list(query)
 
-    # Post-process rows (which won't apply to custom fetches/concats)
     if rows is not None:
         assert table is not None  # Hint for mypy
         response[table] = make_raw(rows, exclude=config.exclude)
-        if table in DATE_FIELDS:
-            floatify_datetime_fields(response, table)
+
+    # Post-process rows
+    for t in exported_tables:
+        if t in DATE_FIELDS:
+            floatify_datetime_fields(response, t)
 
     # Now walk our children.  It's extremely important to respect
     # the order of children here.