[dconf-editor] Handle the empty tuple.

[Arnaud Bonatti <arnaudb src gnome org>]

commit 51d4211257ffa91814671fc14b401ebe0dc55ac8
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Mon Mar 19 12:21:03 2018 +0100

    Handle the empty tuple.

 editor/ca.desrt.dconf-editor.gschema.xml |    5 +++++
 editor/key-list-box-row.vala             |    8 ++++++--
 editor/registry-info.ui                  |   10 ++++++++++
 editor/registry-info.vala                |   10 +++++++---
 editor/setting-object.vala               |    2 ++
 5 files changed, 30 insertions(+), 5 deletions(-)
---
diff --git a/editor/ca.desrt.dconf-editor.gschema.xml b/editor/ca.desrt.dconf-editor.gschema.xml
index e2d3484..ec464e3 100644
--- a/editor/ca.desrt.dconf-editor.gschema.xml
+++ b/editor/ca.desrt.dconf-editor.gschema.xml
@@ -344,6 +344,11 @@
       <summary>A 1-choice integer value</summary>
       <description>A range could limit an integer key to only allow one value, but that’s probably an error. 
Dconf Editor warns you in that case.</description>
     </key>
+    <key name="weird-triv" type="()">
+      <default>()</default>
+      <summary>The empty tuple, type and value “()”</summary>
+      <description>There’s an empty tuple type (called sometimes “triv”) that is a tuple with no content, 
and can only take “()” as value.</description>
+    </key>
   </schema>
   <schema id="ca.desrt.dconf-editor.Demo.Empty" path="/ca/desrt/dconf-editor/Demo/Empty/">
   </schema>
diff --git a/editor/key-list-box-row.vala b/editor/key-list-box-row.vala
index 3e023e6..de86d4c 100644
--- a/editor/key-list-box-row.vala
+++ b/editor/key-list-box-row.vala
@@ -408,7 +408,7 @@ private class KeyListBoxRowEditableNoSchema : KeyListBoxRow
         bool planned_change = modifications_handler.key_has_planned_change (key.full_name);
         Variant? planned_value = modifications_handler.get_key_planned_value (key.full_name);
 
-        if (key.type_string == "b" || key.type_string == "mb")
+        if (key.type_string == "b" || key.type_string == "mb" || key.type_string == "()")
         {
             popover.new_section ();
             bool delayed_apply_menu = modifications_handler.get_current_delay_mode ();
@@ -553,7 +553,8 @@ private class KeyListBoxRowEditable : KeyListBoxRow
                 (key.type_string == "n" || key.type_string == "i" || key.type_string == "h" || 
key.type_string == "x")
                 && (key.range_type == "range")
                 && (Key.get_variant_as_int64 (key.range_content.get_child_value (1)) - 
Key.get_variant_as_int64 (key.range_content.get_child_value (0)) < 13)
-               ))
+               )
+            || key.type_string == "()")
         {
             popover.new_section ();
             GLib.Action action;
@@ -809,6 +810,9 @@ private class ContextPopover : Popover
                            number++)
                     current_section.append (number.to_string (), @"$group_dot_action(@mm$type_string 
$number)");
                 break;
+            case "()":
+                current_section.append ("()", @"$group_dot_action(@mm() ())");
+                break;
         }
 
         ((GLib.ActionGroup) current_group).action_state_changed [ACTION_NAME].connect ((unknown_string, 
tmp_variant) => {
diff --git a/editor/registry-info.ui b/editor/registry-info.ui
index 52d8a28..b338e16 100644
--- a/editor/registry-info.ui
+++ b/editor/registry-info.ui
@@ -159,6 +159,16 @@
                         <property name="label" translatable="yes">This integer key can only take one value. 
That’s probably an error of the application that installed this schema. If possible, please open a bug about 
it.</property>
                       </object>
                     </child>
+                    <child>
+                      <object class="GtkLabel" id="one_choice_tuple_warning">
+                        <property name="visible">True</property>
+                        <property name="hexpand">True</property>
+                        <property name="xalign">0.5</property>
+                        <property name="max-width-chars">40</property>
+                        <property name="wrap">True</property>
+                        <property name="label" translatable="yes">This key has a special “empty tuple” type. 
That’s probably an error of the application that installed this schema. If possible, please open a bug about 
it.</property>
+                      </object>
+                    </child>
                   </object>
                 </child>
               </object>
diff --git a/editor/registry-info.vala b/editor/registry-info.vala
index 943aaf2..6d2833b 100644
--- a/editor/registry-info.vala
+++ b/editor/registry-info.vala
@@ -26,6 +26,7 @@ class RegistryInfo : Grid, BrowsableView
     [GtkChild] private Revealer one_choice_warning_revealer;
     [GtkChild] private Label one_choice_enum_warning;
     [GtkChild] private Label one_choice_integer_warning;
+    [GtkChild] private Label one_choice_tuple_warning;
     [GtkChild] private ListBox properties_list_box;
     [GtkChild] private Button erase_button;
 
@@ -166,9 +167,9 @@ class RegistryInfo : Grid, BrowsableView
         bool is_key_editor_child_single = key_editor_child is KeyEditorChildSingle;
         if (is_key_editor_child_single)
         {
-            bool is_enum = tmp_string == "<enum>";
-            one_choice_integer_warning.visible = !is_enum;
-            one_choice_enum_warning.visible = is_enum;
+            one_choice_enum_warning.visible = tmp_string == "<enum>";
+            one_choice_tuple_warning.visible = tmp_string == "()";
+            one_choice_integer_warning.visible = (tmp_string != "<enum>") && (tmp_string != "()");
         }
         one_choice_warning_revealer.set_reveal_child (is_key_editor_child_single);
 
@@ -334,6 +335,9 @@ class RegistryInfo : Grid, BrowsableView
                     range_content_or_null = ((GSettingsKey) key).range_content;
                 return (KeyEditorChild) new KeyEditorChildNullableBool (initial_value, delay_mode, 
has_planned_change, range_content_or_null);
 
+            case "()":
+                return (KeyEditorChild) new KeyEditorChildSingle (new Variant ("()", "()"), "()");
+
             default:
                 if ("a" in key.type_string)
                     return (KeyEditorChild) new KeyEditorChildArray (key.type_string, initial_value);
diff --git a/editor/setting-object.vala b/editor/setting-object.vala
index ecda72d..40e97ed 100644
--- a/editor/setting-object.vala
+++ b/editor/setting-object.vala
@@ -92,6 +92,8 @@ public abstract class Key : SettingObject
                 return _("Integer");
             case "v":
                 return _("Variant");
+            case "()":
+                return _("Empty tuple");
             default:
                 return type;
         }