#1363 SANE: "Feeder" (simplex) scans both sides with Kodak kds_s2000 — source set to "ADF", duplex option never set

[Bernd Geiselmann]

Environment

• NAPS2 8.2.1, Linux (Zorin OS 18.1 / Ubuntu 24.04 base), x86_64
• Driver: SANE
• Scanner: Kodak Alaris S2050, official Kodak Linux driver, device id "kds_s2000:S2000"

Summary
A profile with paper source "Feeder" (simplex) scans BOTH sides instead of front
only. The source dropdown offers just "Feeder" and "Duplex"; choosing "Feeder"
produces two images per sheet. Duplex profiles work correctly.

Root cause (confirmed via NAPS2 debug log)
This driver exposes two relevant options:
duplex -> StringList: front,back,both (default: both) [non-standard enum]
source -> StringList: ADF,ADF Front,ADF Back,ADF Both,ADF Duplex (default: ADF)

For a Feeder profile, NAPS2 sets the source to plain "ADF" and never sets the
"duplex" option, so it stays at its default "both" -> both sides scanned.

Relevant debug log lines:
Scan source: Feeder; bit depth: BlackAndWhite; dpi: 300; page size: 210x297 mm
Option: 5 duplex Duplex Mode ... StringList front,back,both
Option: 13 source Scan source ... StringList ADF,ADF Front,ADF Back,ADF Both,ADF Duplex
Maybe setting source
Setting source to ADF
(No "Setting duplex ..." line appears anywhere.)

Confirmed simplex via scanimage (single sheet, batch mode -> 1 image each):
scanimage -d 'kds_s2000:S2000' --source 'ADF Front' # 1 page (front only)
scanimage -d 'kds_s2000:S2000' --source 'ADF' --duplex front # 1 page (front only)

Suggested fix
For PaperSource=Feeder on backends exposing this pattern, either select the
"ADF Front" source value when present, and/or explicitly set the "duplex" option
to "front" -- i.e. handle the front|back|both enum form, not only boolean yes|no.
(Correspondingly set duplex=both / source "ADF Duplex" for the Duplex case.)

Full debug log attached.