Uploading of a malformed ppd leads to bad user experience

[ajoga]

Summary

Uploading a malformed PPD shows a successful upload, but of course on the Add printer page the corresponding driver is absent from the Driver name menu.

Steps to reproduce

Facultative : get official PPD from authoritative source

Fetch the PPDs from http://download.ebz.epson.net/dsc/search/01/search/?OSC=LX for the C3900 laser printer. It is also attached to this issue here.

Steps to reproduce

• Upload the bad PPD.
• The user can see the uploaded file :

• Go to the Add printer page. In Driver name, Epson AL-C3900 is nowhere to be found.

Hints

I was put on track about the malformed PPD thanks to a warning in the logs : W [2022-02-18T13:32:20.164Z] libppd: [PPD Collections] Missing Product in /var/snap/ps-printer-app/common/ppd//secc3900.ppd!

Thankfully the tool cupstestppd made me on track that the Product property of the PPD was misformatted ; setting it from the original value of EPSON AL-C3900 to (AL-C3900) leads ps-printer-app to display the printer in the Driver name menu :

Expected hebavior

• When uploading an unusable PPD, it could be rejected with an en-user friendly error including the log line above
• When an exception is making the PPD unusable, maybe raise more than a warning ? Or maybe give a hint on the UX including the log line above ?

[tillkamppeter]

Now uploading a malformed PPD warns the user with the same output as cupstestppd does. The PPD will not get rejected but at least the user gets warned.

Thanks, @metabiswadeep for your great work on this!