From 2d511e2ab555fa3d08c88ca7be6eff2043c516b9 Mon Sep 17 00:00:00 2001
From: Uli Schlachter <psychon@znc.in>
Date: Sat, 4 Jun 2016 15:56:52 +0200
Subject: [PATCH] gears.object.properties: Implement read-only properties

Signed-off-by: Uli Schlachter <psychon@znc.in>
---
 lib/awful/screen.lua            | 14 --------------
 lib/gears/object/properties.lua |  5 +++++
 tests/test-miss-handlers.lua    |  4 ++++
 3 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/lib/awful/screen.lua b/lib/awful/screen.lua
index 9073dd9f..162628cf 100644
--- a/lib/awful/screen.lua
+++ b/lib/awful/screen.lua
@@ -311,8 +311,6 @@ function screen.object.get_clients(s)
     return vcls
 end
 
-function screen.object.set_clients() end
-
 --- Get the list of the clients assigned to the screen but not currently
 -- visible.
 --
@@ -335,8 +333,6 @@ function screen.object.get_hidden_clients(s)
     return vcls
 end
 
-function screen.object.set_hidden_clients() end
-
 --- Get all clients assigned to the screen.
 --
 -- @property all_clients
@@ -349,8 +345,6 @@ function screen.object.get_all_clients(s)
     return capi.client.get(s, true)
 end
 
-function screen.object.set_all_clients() end
-
 --- Get the list of the screen tiled clients.
 --
 -- Same as s.clients, but excluding:
@@ -377,8 +371,6 @@ function screen.object.get_tiled_clients(s)
     return tclients
 end
 
-function screen.object.set_tiled_clients() end
-
 --- Call a function for each existing and created-in-the-future screen.
 -- @function awful.screen.connect_for_each_screen
 -- @tparam function func The function to call.
@@ -425,8 +417,6 @@ function screen.object.get_tags(s, unordered)
     return tags
 end
 
-function screen.object.set_tags() end
-
 --- A list of all selected tags on the screen.
 -- @property selected_tags
 -- @param table
@@ -446,8 +436,6 @@ function screen.object.get_selected_tags(s)
     return vtags
 end
 
-function screen.object.set_selected_tags() end
-
 --- The first selected tag.
 -- @property selected_tag
 -- @param table
@@ -459,8 +447,6 @@ function screen.object.get_selected_tag(s)
     return screen.object.get_selected_tags(s)[1]
 end
 
-function screen.object.set_selected_tag() end
-
 
 --- When the tag history changed.
 -- @signal tag::history::update
diff --git a/lib/gears/object/properties.lua b/lib/gears/object/properties.lua
index 9b988682..f528482a 100644
--- a/lib/gears/object/properties.lua
+++ b/lib/gears/object/properties.lua
@@ -83,6 +83,11 @@ function object.capi_index_fallback(class, args)
             return args.setter_fallback(cobj, prop, value)
         end
 
+        -- If a getter exists but not a setter, then the property is read-only
+        if args.getter_class and args.getter_class[getter_prefix..prop] then
+            return
+        end
+
         local fallback = properties[cobj] or cobj_register(cobj)
 
         -- Use the fallback property table
diff --git a/tests/test-miss-handlers.lua b/tests/test-miss-handlers.lua
index 258cbb99..46cfad2c 100644
--- a/tests/test-miss-handlers.lua
+++ b/tests/test-miss-handlers.lua
@@ -40,4 +40,8 @@ local w = wibox()
 w.foo = "bar"
 assert(w.foo == "bar")
 
+-- Test if read-only properties really are read-only
+screen[1].clients = 42
+assert(screen[1].clients ~= 42)
+
 require("_runner").run_steps({ function() return true end })