Hammerspoon: Window hints - error - attempt to index a nil value

[ztomer]

I occasionally get the following error when a Steam window is opened after Hammerspoon (v0.9.24) was loaded:
(but not when steam is opened before Hammerspoon is loaded)

...poon.app/Contents/Resources/extensions/hs/hints/init.lua:80: attempt to index a nil value
stack traceback:
    ...poon.app/Contents/Resources/extensions/hs/hints/init.lua:80: in function 'displayHintsForDict'
    ...poon.app/Contents/Resources/extensions/hs/hints/init.lua:174: in function <...poon.app/Contents/Resources/extensions/hs/hints/init.lua:149>
    [C]: in function 'xpcall'
    ...oon.app/Contents/Resources/extensions/hs/hotkey/init.lua:23: in function <...oon.app/Contents/Resources/extensions/hs/hotkey/init.lua:21>

[cmsj]

This is very odd, it looks, from the code, like either the Steam window has no :screen() value, or the screen has no :frame() value, neither of which should be possible!

How occasionally does it happen? I guess I need to install Steam and see if I can reproduce :)

[ztomer]

I'm not sure about the regularity - tried it now and it didn't misbehave, on other occasions, it crashes regularly.

More information: the steam window cannot be controlled using Hammerspoon - trying to move/resize it doesn't work (the window flickers, shows an image on the target location, and returns to the original position - it may or may not be related).

[cmsj]

This will be fixed when #256 lands :)

[trishume]

Now I know which app was causing my problems :P

I had Steam running as well.

[tnorthcutt]

This seems to be biting me with PhpStorm. This code in init.lua:

hs.hotkey.bind(hyper, "Up", function()
  local win = hs.window.focusedWindow()
  local f = win:frame()
  local screen = win:screen()
  local max = screen:frame()

  f.x = max.x
  f.y = max.y
  f.w = max.w
  f.h = max.h
  win:setFrame(f)
end)

Results in this console output:

/Users/travis/.hammerspoon/init.lua:125: attempt to index a nil value (local 'win')
stack traceback:
    /Users/travis/.hammerspoon/init.lua:125: in function </Users/travis/.hammerspoon/init.lua:121>
stack traceback:

I'm very new to Hammerspoon, but I dug around and found the id of the window object I'm trying to operate on, and it looks like it indeed doesn't have a :frame() value.

Any suggestions on a workaround? Or, any ways I can provide better debug info and possibly help fix this behavior? Like I said, I'm new to Hammerspoon (and Lua), but I'm happy to try to put together a PR if someone can point me in the right direction.

[trishume]

@tnorthcutt Your issue is unrelated to this Github issue, but that's okay, I'm happy to attempt to help.

attempt to index a nil value (local 'win') sounds more like win is nil, which would happen if you used this shortcut without a focused window, which can happen sometimes on OSX.

[lowne]

@tnorthcutt if the problem is hs.window.focusedWindows() returns nil, try using hs.window.frontmostWindow() instead; otherwise, to debug easily from the console, you can use hs.window.find() (or just hs.window()) with part of the title; for example (I use the Hammerspoon Console window itself in this example, substitute in the first command acordingly):

> w=hs.window'console'

> w
hs.window: Hammerspoon Console (0x7fc887a9e018)

> w:frame()
hs.geometry.rect(2688.0,23.0,1152.0,1066.0)

If w is nil, then no window was found; if w is valid, but w:frame() returns nil, then it's a different problem that needs further scrutiny.

[tnorthcutt]

@trishume @lowne thanks for the replies. Unfortunately this is both an issue of hs.window.focusedWindow() returning a window object, but that object not having a :frame() object (I hope my terminology is correct), and it being an intermittent issue, which I can't reproduce this time. I'll try some more things to get it reproducible then try those suggestions @lowne.

Cheers!

[tnorthcutt]

This popped up again today, so I tried switching to frontmostWindow() as per @lowne's suggestion, and it worked! Thanks for the help.

[loisaidasam]

I was experiencing similar issues in OSX for both focusedWindow() and frontmostWindow() returning nil, and found this solution:

https://stackoverflow.com/questions/34743870/lua-hammerspoon-hs-window-focusedwindow-is-nil-when-assigned-to-a-variable

which suggests going to:

System Preferences > Security & Privacy > Privacy tab > Accessibility

and then check the box to allow Hammerspoon to control your computer