completion, util: Check for io.popen failure.

Signed-off-by: Maarten Maathuis <madman2003@gmail.com>
Signed-off-by: Julien Danjou <julien@danjou.info>

lib/awful/completion.lua.in

@@ -9,6 +9,7 @@
 local io = io
 local table = table
 local math = math
+local print = print
 
 --- Completion module for awful
 module("awful.completion")
@@ -26,7 +27,8 @@ keywords = {}
 -- @param src The bash completion source file, /etc/bash_completion by default.
 function bashcomp_load(src)
     if src then bashcomp_src = src end
-    local c = io.popen("/usr/bin/env bash -c 'source " .. bashcomp_src .. "; complete -p'")
+    local c, err = io.popen("/usr/bin/env bash -c 'source " .. bashcomp_src .. "; complete -p'")
+    if c then
         while true do
             local line = c:read("*line")
             if not line then break end
@@ -36,6 +38,9 @@ function bashcomp_load(src)
             end
         end
         c:close()
+    else
+        print(err)
+    end
 end
 
 --- Use bash completion system to complete command and filename.
@@ -88,9 +93,10 @@ function bash(command, cur_pos, ncomp)
     else
         bash_cmd = "/usr/bin/env bash -c 'compgen -A " .. comptype .. " " .. words[cword_index] .. "'"
     end
-    local c = io.popen(bash_cmd)
+    local c, err = io.popen(bash_cmd)
     local output = {}
     i = 0
+    if c then
         while true do
             local line = c:read("*line")
             if not line then break end
@@ -98,6 +104,9 @@ function bash(command, cur_pos, ncomp)
         end
 
         c:close()
+    else
+        print(err)
+    end
 
     -- no completion, return
     if #output == 0 then

lib/awful/util.lua.in

@@ -73,10 +73,14 @@ end
 -- @return A string with the program output.
 function pread(cmd)
     if cmd and cmd ~= "" then
-        local f = io.popen(cmd, 'r')
+        local f, err = io.popen(cmd, 'r')
+        if f then
             local s = f:read("*all")
             f:close()
             return s
+        else
+            print(err)
+        end
     end
 end