Password protected PDF causes crash

[gjask]

Current behaviour

When I try to open password protected PDF file the application crashes.

Expected behaviour

Either a dialog asking for password should pop up and the application should use that password to decrypt the file and continue as usual. Or a dialog informing about why protected files cannot be used could be shown instead.

How to reproduce

1. create password protected PDF or download this one test-protected.pdf
2. try to open it in PDFSlicer

Context

# Running PDFSlicer from terminal to get output logged
[jask@hal3042 ~]$ flatpak run com.github.junrrein.PDFSlicer
[2022-06-08 14:51:58.853] [default] [info] Welcome to PDF Slicer
[2022-06-08 14:51:58.853] [default] [info] Logging to file: /home/jask/.var/app/com.github.junrrein.PDFSlicer/config/com.github.junrrein.PDFSlicer/log.txt
poppler/error: Incorrect password
poppler/error: Incorrect password

# Checking return code
[jask@hal3042 ~]$ echo $?
139

# Checking log
[jask@hal3042 ~]$ cat /home/jask/.var/app/com.github.junrrein.PDFSlicer/config/com.github.junrrein.PDFSlicer/log.txt
[2022-06-08 10:54:48.025] [default] [info] Welcome to PDF Slicer
[2022-06-08 10:54:48.025] [default] [info] Logging to file: /home/jask/.var/app/com.github.junrrein.PDFSlicer/config/com.github.junrrein.PDFSlicer/log.txt
[2022-06-08 10:54:48.167] [default] [warning] Error while loading config file: No such file or directory
[2022-06-08 10:54:48.180] [default] [warning] Error while loading window state: Soubor klíče nemá skupinu „window-state“
[2022-06-08 10:54:48.180] [default] [warning] Error while loading zoom level: Soubor klíče nemá skupinu „misc“