Uploading multiple files with “Save to Files” fails, says it “doesn’t exist”

Expected behavior

Uploading multiple files or photos to Nextcloud with Save to Files should mark them for upload correctly and quickly.

Actual behavior

Selecting multiple files from Files or media from Photos, then using Save to Files to try to save to Nextcloud gives the error:

Can’t Copy “Filename.EXT”

The file “Filename.EXT” couldn’t be copied because it either doesn’t exist or the folder it is being copied to doesn’t exist.

If you do a single file/photo at a time, then it goes through, but doesn’t actually upload anyway thanks to issue #1018 that I reported long ago.

Steps to reproduce

Select multiple files from the Files app or multiple media from the Photos app, press the share button, and use Save to Files. Choose any location inside Nextcloud including the root directory. Press Save.

iOS version

13.3

App version

2.25.3.6

Server configuration

Operating system: Debian (Docker)

Web server: Apache?

Database: mysql 10.4.11

PHP version: 7.3.13

Nextcloud version: 16.0.4

Start by reproducing the Save to Files share flow with multiple files from Files or Photos, using the reported iOS and app versions as context. Trace the upload handoff for multiple selections and compare it with the single-file path; done means multiple items are accepted, saved to a Nextcloud location, and actually uploaded rather than showing the copy error.