backslash(es) in markdown code let joplin freeze (forever)

[chrismade]

Environment

Joplin version: Joplin 2.1.9 (prod, win32) - happened also on earlier version (but I was not able to deliver repro instructions)
Platform: win32
OS specifics:

Client ID: 9803ea6e019c41fc90ce229638d50153
Sync Version: 2
Profile Version: 39
Keychain Supported: No

Revision: 882d663

Steps to reproduce

1. take a text like this
   D:\daten\muell>dir \s\b
   D:\daten\muell\boot.img
   D:\daten\muell\dtbo.img
   D:\daten\muell\install
   D:\daten\muell\META-INF
   D:\daten\muell\system.new.dat.br
   D:\daten\muell\system.patch.dat
   D:\daten\muell\system.transfer.list
   D:\daten\muell\vbmeta.img

2. open any note - switch into markdown editor and find (or create a code block - using the 3 backticks )
   or doubleclick on an existing code in RTF editor which open the code editor
   try to insert with copy/paste the text from [1] or likely any other text that contains backslash like the text from [1]

3. Joplin freezes immediately - reboot does not help - Joplin freezes on open - only remedy is to remove folder "JoplinProfile" and start re-sync (if you are lucky to have your notes synced somewhere - nextcloud in my case)

Describe what you expected to happen

expected to insert this text like any other text on paste -

if I replace all backslash by regular slash everything works as expected - text is inserted, no freeze

Logfile

I have the logfiles but it seems these do not contain any useful info regarding this issue as freeze happens immediately - of course I will upload logfile on request but instructions above should help to repro the case even without logfile

[laurent22]

I cannot replicate this issue. Any chance you could switch to safe mode (Under Help menu), then right-click on the note and export as JEX? That way we'll have the exact note to replicate the issue.

[chrismade]

@laurent22 - I agree the procedure above cannot repro the issue - but thanks to your instructions I created a note in "safe" mode, exported as JEX - and the moment I toggle from "safe" to "regular" it freezes -
07_08_2021.txt

file renamed from JEX to TXT - can you repro the issue with that file ?

[roman-r-m]

I can reproduce it with your file
This is coming from highlight.js, looks very similar to this issue highlightjs/highlight.js#2375 although that exact bug is fixed in the version Joplin is using.

[roman-r-m]

Upgrading highlight.js to the latest version fixes it.

[chrismade]

wow I deeply impressed - I guess that's something which comes with the exe file and I can't fix it myself, right ?
btw - Joplin is an excellent tool, OneNote is now history for me (still need to convert a few hundred notes) - pls keep up the good work!

[roman-r-m]

wow I deeply impressed - I guess that's something which comes with the exe file and I can't fix it myself, right ?

i think setting language explicitly would help in this particular case. something like

```bat

...

```

[laurent22]

@roman-r-m, do you have a working version of it? And if so, any chance you could create a PR with it?

[roman-r-m]

Sure: #5278

I haven't tested it much, only verified that the above attached file no longer causes Joplin to freeze + a few basic checks.