ges: docs: fix enum value extraction for enums with gaps

Handle enums like GstBaseTextOverlayHAlign that have missing values
by dynamically calculating the actual range needed and skipping
invalid enum values instead of creating placeholder entries.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/9495>

subprojects/gst-editing-services/docs/libs/document-children-props.py

@@ -42,8 +42,18 @@ def get_enum_values_from_property(prop):
 
     values = []
 
+    # In some cases there are 'gaps' like in the GstBaseTextOverlayHAlign where
+    # value 3 is GST_BASE_TEXT_OVERLAY_HALIGN_UNUSED - so we need to compensate
+    # for the gap
+    n_values = enum_class.n_values
+    for i in range(n_values):
+        try:
+            enum_type(i)
+        except Exception:
+            n_values += 1
+
     # Get all enum values by creating them with integer values
-    for i in range(enum_class.n_values):
+    for i in range(n_values):
         try:
             # For other values, create them using the enum type
             enum_val = enum_type(i)
@@ -56,9 +66,9 @@ def get_enum_values_from_property(prop):
                     first_val = enum_class.values
                     values.append((first_val.value, first_val.value_name, first_val.value_nick))
                 except Exception:
-                    values.append((i, f"Value_{i}", f"value-{i}"))
+                    continue
             else:
-                values.append((i, f"Value_{i}", f"value-{i}"))
+                continue
 
     return values
 
@@ -98,7 +108,6 @@ if __name__ == "__main__":
             element, gtype = element
         else:
             gtype = element.__gtype__.name
-        print(gtype)
         with open(gtype + '-children-props.md', 'w') as f:
             for prop in GES.TimelineElement.list_children_properties(element):
                 prefix = '#### `%s`\n\n' % (prop.name)