[glib: 1/2] gio: Document g_settings_new() missing schema behaviour

[Philip Withnall <pwithnall src gnome org>]

commit dc1a1b841cb6a7902d019284a054cce75f04dc14
Author: Chris Mayo <aklhfex gmail com>
Date:   Mon Aug 24 09:02:43 2020 +0000

    gio: Document g_settings_new() missing schema behaviour
    
    Explain what happens, the rationale and reference another
    function that may be helpful.

 gio/gsettings.c | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/gio/gsettings.c b/gio/gsettings.c
index eeb9e3bbe..4332ebe44 100644
--- a/gio/gsettings.c
+++ b/gio/gsettings.c
@@ -961,6 +961,12 @@ g_settings_class_init (GSettingsClass *class)
  * Creates a new #GSettings object with the schema specified by
  * @schema_id.
  *
+ * It is an error for the schema to not exist: schemas are an
+ * essential part of a program, as they provide type information.
+ * If schemas need to be dynamically loaded (for example, from an
+ * optional runtime dependency), g_settings_schema_source_lookup()
+ * can be used to test for their existence before loading them.
+ *
  * Signals on the newly created #GSettings object will be dispatched
  * via the thread-default #GMainContext in effect at the time of the
  * call to g_settings_new().  The new #GSettings will hold a reference