Awesome: Crash when using a custom keyboard layout

[hishamhm]

Output of awesome --version:

awesome  (The Fox)
 • Compiled against Lua 5.3.3 (running with Lua 5.3)
 • D-Bus support: ✔

How to reproduce the issue:

I am using a custom keyboard layout (a variant of Dvorak with accents; for the record, in my system awesome.xkb_get_group_names() returns pc+dvorak_alt2+inet(evdev)).

Actual result:

Whenever I restart Awesome with an error in my ~/.config/awesome/rc.lua, which should have caused the default config to load, instead I get a fatal error: X terminates and I'm back to the console. Piping awesome to a log file, I found that I got the following Lua error:

Failed to get list of keyboard groups

Triggered at awful/widget/keyboardlayout.lua:

local function update_layout(self)
    self._layout = {};
    local layouts = keyboardlayout.get_groups_from_group_names(awesome.xkb_get_group_names())
    if layouts == nil or layouts[1] == nil then
        error("Failed to get list of keyboard groups")
        return;
    end
    if #layouts == 1 then
        layouts[1].group_idx = 0
    end
    for _, v in ipairs(layouts) do
        local layout_name = self.layout_name(v)
        -- Please note that numbers of groups reported by xkb_get_group_names
        -- is greater by one than the real group number.
        self._layout[v.group_idx - 1] = layout_name
    end
    update_status(self)
end

Interestingly, loading Awesome with the default config works, but restarting always shuts down X.

Expected result:

I simply commented out the error("Failed to get list of keyboard groups") line and everything works as expected: Awesome doesn't terminate and my keyboard works the way I configured it; it seems to me that not finding a standard keyboard layout should not be a fatal error.

I can provide more info if desired. Thank you!

[blueyed]

Can you poke into get_groups_from_group_names and print things there, please?
You can use require("gears").debug.dump(data, "desc") for that.
Of course also the return value is interesting (layouts): is it nil or is layouts[1] nil?

Oh, and trying it with awesome from Git (if you easily can) would be nice, too.

[psychon]

I'd like to try to reproduce this. However, of course I do not have dvorak_alt2. You do provide a link to it in your report. However, what exactly do I do with the files I have there?

[hishamhm]

@psychon thanks! But I'll get the information that @blueyed asked for as soon as I'm at the computer again, I hope that should be enough to diagnose the problem without making you unconfigure your keyboard :)

[psychon]

Oh, I just remembered that keyboardlayout is covered by unit tests, so the following patch can be used to reproduce the problem (kinda):

diff --git a/spec/awful/keyboardlayout_spec.lua b/spec/awful/keyboardlayout_spec.lua
index e2a5c96..f7d396e 100644
--- a/spec/awful/keyboardlayout_spec.lua
+++ b/spec/awful/keyboardlayout_spec.lua
@@ -14,6 +14,8 @@ describe("awful.widget.keyboardlayout get_groups_from_group_names", function()
         -- possible worst cases
         [""] = {
         },
+        ["pc+dvorak_alt2+inet(evdev)"] = {
+        },
         ["empty"] = {
         },
         ["empty(basic)"] = {

So this returns an empty table.

Looking at what get_groups_from_group_names does, it splits the string into parts delimited by "+". For each of these parts it tries to figure out a country. Well, none of it is.

When I do e.g. setxkbmap dvorak, awesome gets pc+us(dvorak)+inet(evdev) and can parse the us part of this. So your dvorak_alt2-layout just has a name that this code does not expect.

So I guess the issue here boils down to "the keyboardlayout widget expects a specific format of the 'XKB group names thing'; however, this expectation is wrong and should be lifted". I suggest: Instead of erroring out, the code prints a warning (via gears.debug) and produces an empty widget.

[hishamhm]

I think @psychon's assessment is spot on. In any case, here's the answers to the clarifications that were requested:

Can you poke into get_groups_from_group_names and print things there, please?
You can use require("gears").debug.dump(data, "desc") for that.

I get three tokens, "pc", "dvorak2_alt" and "inet(evdev)".

Of course also the return value is interesting (layouts): is it nil or is layouts[1] nil?

The return value is an empty table.

Oh, and trying it with awesome from Git (if you easily can) would be nice, too.

This was running 25f2b034 — I don't think this part of the code change since, but I can try updating if you find it necessary!

I agree that changing that error() into a warning is the best course of action (especially since it's non-fatal and the desktop runs fine when it fails to detect the keyboard layout). Thank you both for the prompt responses! :)

[psychon]

I'd suggest

diff --git a/lib/awful/widget/keyboardlayout.lua b/lib/awful/widget/keyboardlayout.lua
index b6e8ce0..ab0c56a 100644
--- a/lib/awful/widget/keyboardlayout.lua
+++ b/lib/awful/widget/keyboardlayout.lua
@@ -11,6 +11,7 @@ local textbox = require("wibox.widget.textbox")
 local button = require("awful.button")
 local util = require("awful.util")
 local widget_base = require("wibox.widget.base")
+local gdebug = require("gears.debug")

 --- Keyboard Layout widget.
 -- awful.widget.keyboardlayout
@@ -234,8 +235,8 @@ local function update_layout(self)
     self._layout = {};
     local layouts = keyboardlayout.get_groups_from_group_names(awesome.xkb_get_group_names())
     if layouts == nil or layouts[1] == nil then
-        error("Failed to get list of keyboard groups")
-        return;
+        gdebug.print_error("Failed to get list of keyboard groups")
+        return
     end
     if #layouts == 1 then
         layouts[1].group_idx = 0

[Elv13]

Looks like this could be merged. @hishamhm you +1-ed this, so it works for you?

[hishamhm]

@Elv13 yes, it does!

[blueyed]

Great, I will create a PR in @psychon's name.

[blueyed]

@psychon
The test (from https://github.com/awesomeWM/awesome/issues/1108#issuecomment-248904455) did not fail: https://github.com/awesomeWM/awesome/pull/1152#issuecomment-252362421

[psychon]

Sorry if I wasn't clear.

No, this test should not fail. It shows that this keyboard layout description will be parsed into an empty table (no language-specific entries found). The following code then raises an error claiming that something was wrong:

    if layouts == nil or layouts[1] == nil then
        error("Failed to get list of keyboard groups")

The idea of this test was more "via this one (at least I) can understand what is actually happening".