Does not start on Kobo Touch (attempt to call field 'isKindle')

[RenaKunisaki]

• KOReader version: koreader-kobo-v2019.12
• Device: Kobo Touch model N905C

Issue

Koreader crashes immediately at startup.

Steps to reproduce

1. Install KSM 09
2. Install Koreader
3. Boot
4. Select "start koreader"

crash.log (if applicable)

crash.log

[RenaKunisaki]

Quick and dirty patch to fontlist.lua to get it working:

63c63,64
<     return CanvasContext.isKindle() and kindle_fonts_blacklist[f]
---
>     --return CanvasContext.isKindle() and kindle_fonts_blacklist[f]
>       return false
67,69c68,70
<     if CanvasContext.isAndroid() or CanvasContext.isDesktop() then
<         return require("frontend/ui/elements/font_settings"):getPath()
<     else
---
>     --if CanvasContext.isAndroid() or CanvasContext.isDesktop() then
>     --    return require("frontend/ui/elements/font_settings"):getPath()
>     --else
71c72
<     end
---
>     --end

[poire-z]

./luajit: frontend/fontlist.lua:63: attempt to call field 'isKindle' (a nil value)
stack traceback:
    frontend/fontlist.lua:63: in function 'isInFontsBlacklist'
    frontend/fontlist.lua:87: in function '_readList'
    frontend/fontlist.lua:81: in function '_readList'
    frontend/fontlist.lua:98: in function 'getFontList'
    frontend/ui/font.lua:247: in function 'getFace'
    ./tools/kobo_touch_probe.lua:76: in function 'init'
    frontend/ui/widget/widget.lua:48: in function 'new'
    frontend/device/kobo/device.lua:375: in function 'touchScreenProbe'
    ./reader.lua:141: in main chunk

The crash is similar to the one we investigated in #5688, but not the reason.

koreader/reader.lua

Lines 139 to 158 in d647c62

	-- Touch screen
	if Device:needsTouchScreenProbe() then
	Device:touchScreenProbe()
	end
	-- Handle global settings migration
	local SettingsMigration = require("ui/data/settings_migration")
	SettingsMigration:migrateSettings(G_reader_settings)
	-- Document renderers canvas
	local CanvasContext = require("document/canvascontext")
	CanvasContext:init(Device)
	-- UI mirroring for RTL languages, and text shaping configuration
	local Bidi = require("ui/bidi")
	Bidi.setup(lang_locale)
	-- Avoid loading UIManager and widgets before here, as they may
	-- cache Bidi mirroring settings. Check that with:
	-- for name, _ in pairs(package.loaded) do print(name) end

I think the real fix is moving lines 139-142 after line 158, as Device:touchScreenProbe() may do UIManager:show(TouchProbe:new{}).
Can you revert your quick and dirty patch, and try it, and tell us if it works and you don't see other bad things?

Although I know nothing about that tools/kobo_touch_probe.lua. Is that supposed to be a one-time thingy? Would it be too late to have that done on line 158?
Was that a first/fresh install, without any config/settings that would have been carried from a previous version?

[NiLuJe]

The probe is done on Device init, IIRC. Possibly once only, I can't recall.

EDIT: Or it's its result that's used on Device init, which would explain the current order... :/.

[Frenzie]

Should be only once because it stores the result.

[poire-z]

OK, so it should be an issue only on first install on Kobo touch (so, hopefully no real need to release a 2019-12.2...)
So, the logical change would be this (even if language/bidi would be english & LTR on first launch after fresh install):

--- a/reader.lua
+++ b/reader.lua
@@ -134,23 +134,26 @@ if Device:hasEinkScreen() then
     end
     if Device.screen.sw_dithering and G_reader_settings:isTrue("dev_no_sw_dither") then
         Device.screen:toggleSWDithering()
     end
 end
--- Touch screen
-if Device:needsTouchScreenProbe() then
-    Device:touchScreenProbe()
-end

 -- Handle global settings migration
 local SettingsMigration = require("ui/data/settings_migration")
 SettingsMigration:migrateSettings(G_reader_settings)

 -- Document renderers canvas
 local CanvasContext = require("document/canvascontext")
 CanvasContext:init(Device)

+-- Touch screen (this may display some widget, on first install on Kobo Touch,
+-- so have it done after CanvasContext:init() but before Bidi.setup() to not
+-- have mirroring mess x/y probing).
+if Device:needsTouchScreenProbe() then
+    Device:touchScreenProbe()
+end
+
 -- UI mirroring for RTL languages, and text shaping configuration
 local Bidi = require("ui/bidi")
 Bidi.setup(lang_locale)
 -- Avoid loading UIManager and widgets before here, as they may
 -- cache Bidi mirroring settings. Check that with:

@RenaKunisaki : can you try by just replacing koreader/reader.lua with this one: reader.lua.txt
(after removing your quick & dirty patch, and backuping/removing any settings.reader.lua).
Testing a first launch (if you see some touch screen probe widget), and subsequent launches (you shouldn't see it anymore).

[RenaKunisaki]

@RenaKunisaki : can you try by just replacing koreader/reader.lua with this one: reader.lua.txt
(after removing your quick & dirty patch, and backuping/removing any settings.reader.lua).
Testing a first launch (if you see some touch screen probe widget), and subsequent launches (you shouldn't see it anymore).

Yep, that seems to have done it.