awful: Move the backward compatibility code into its own file.

The reason for this is that as more of CAPI is brought in line with the
current API guidelines, it is more and more likely the tests will hit
APIs shims (either to test them or because the prototype remains the
same and only the implementation moved to Lua).

docs/config.ld

@@ -133,6 +133,7 @@ file = {
         -- documentation
         '../lib/awful/autofocus.lua',
         '../lib/awful/dbus.lua',
+        '../lib/awful/_compat.lua',
         '../lib/awful/init.lua',
         '../lib/awful/remote.lua',
         '../lib/awful/screen/dpi.lua',

lib/awful/_compat.lua

@@ -0,0 +1,27 @@
+-- This file contains all global backward compatibility workarounds for the
+-- Core API changes.
+local gtimer = require("gears.timer")
+local util   = require("awful.util" )
+local spawn  = require("awful.spawn")
+local gdebug = require("gears.debug")
+
+function timer(...) -- luacheck: ignore
+    gdebug.deprecate("gears.timer", {deprecated_in=4})
+    return gtimer(...)
+end
+
+util.spawn = function(...)
+   gdebug.deprecate("awful.spawn", {deprecated_in=4})
+   return spawn.spawn(...)
+end
+
+util.spawn_with_shell = function(...)
+   gdebug.deprecate("awful.spawn.with_shell", {deprecated_in=4})
+   return spawn.with_shell(...)
+end
+
+util.pread = function()
+    gdebug.deprecate("Use io.popen() directly or look at awful.spawn.easy_async() "
+            .. "for an asynchronous alternative", {deprecated_in=4})
+    return ""
+end

lib/awful/init.lua

@@ -6,34 +6,7 @@
 -- @module awful
 ---------------------------------------------------------------------------
 
--- TODO: This is a hack for backwards-compatibility with 3.5, remove!
-local util = require("awful.util")
-local gtimer = require("gears.timer")
-local gdebug = require("gears.debug")
-function timer(...) -- luacheck: ignore
-    gdebug.deprecate("gears.timer", {deprecated_in=4})
-    return gtimer(...)
-end
-
---TODO: This is a hack for backwards-compatibility with 3.5, remove!
--- Set awful.util.spawn* and awful.util.pread.
-local spawn = require("awful.spawn")
-
-util.spawn = function(...)
-   gdebug.deprecate("awful.spawn", {deprecated_in=4})
-   return spawn.spawn(...)
-end
-
-util.spawn_with_shell = function(...)
-   gdebug.deprecate("awful.spawn.with_shell", {deprecated_in=4})
-   return spawn.with_shell(...)
-end
-
-util.pread = function()
-    gdebug.deprecate("Use awful.spawn.easy_async() "
-            .. "for an asynchronous alternative", {deprecated_in=4})
-    return ""
-end
+require("awful._compat")
 
 return
 {
@@ -60,7 +33,7 @@ return
     titlebar = require("awful.titlebar");
     rules = require("awful.rules");
     popup = require("awful.popup");
-    spawn = spawn;
+    spawn = require("awful.spawn");
 }
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80