consistent crash on file load

[BrainDamage]

• KOReader version: v2019.04-14-g58d88b1
• Device: Kobo Aura H2O2

Issue

consistent crash on file load ( the file is possibly corrupted )

crash.log (if applicable)

crash.log

[NiLuJe]

Yep, it is.

[Frenzie]

Ah, this is the background to #4929.

I'm surprised MuPDF takes down the whole program here.

[Frenzie]

How did you manage to save the last opened document if it crashed, btw?

[BrainDamage]

I simply pressed "open next file" at the end of a file, from a previous file in the same folder.
It launched the current one, saved settings ( I guess ) and then crashed

[Frenzie]

But that's not how it works. If I open a file and crash the program, the in memory settings crash with it. Something like the last opened document will be lost. Generally speaking I consider this a bug, not a feature, but those settings will only be saved in case of a clean exit. Never in between. Settings pertaining to a specific document will be saved when exiting the document. This too is a bug, for which I've prepared a solution but I haven't wanted to tackle migration.

If you purposefully edit the last file pointer to a broken file or break the file afterward, you'll see this on startup:

On closer inspection of your log, the program does not actually crash. It seems to quit when it should be showing you the file browser. Do you have any special settings?

INFO  quitting uimanager
04/16/19-16:18:44 INFO  no dialog left to show

[Frenzie]

Oh, never mind. There's a code path that leads to a proper exit, possibly to prevent memory corruption? That's what'll cause it to save the last opened file.

koreader/frontend/apps/reader/readerui.lua

Lines 465 to 484 in 717db55

	function ReaderUI:showReaderCoroutine(file, provider)
	UIManager:show(InfoMessage:new{
	text = T(_("Opening file '%1'."), file),
	timeout = 0.0,
	})
	-- doShowReader might block for a long time, so force repaint here
	UIManager:forceRePaint()
	UIManager:nextTick(function()
	logger.dbg("creating coroutine for showing reader")
	local co = coroutine.create(function()
	self:doShowReader(file, provider)
	end)
	local ok, err = coroutine.resume(co)
	if err ~= nil or ok == false then
	io.stderr:write('[!] doShowReader coroutine crashed:\n')
	io.stderr:write(debug.traceback(co, err, 1))
	UIManager:quit()
	end
	end)
	end

It can be easily triggered by this CBZ test file. It's a random source code file renamed .png.

not-a-png.cbz.zip

I've never encountered this code path before, in the past five years. ;-)