Problem with libustream-mbedtls and libubox in SNAPSHOT r11814-0b7d779dcf

opkg install libustream-mbedtls
Installing libustream-mbedtls20150806 (2019-11-05-c9b66682-1) to root...
Installing libubox20170601 (2019-11-24-07413cce-1) to root...
Collected errors:
 * check_data_file_clashes: Package libubox20170601 wants to install file /lib/
	But that file is already provided by package  * libubox20191226
 * opkg_install_cmd: Cannot install package libustream-mbedtls.

In a situation like this, do I use --force-depends or --nodeps or both?

In a situation like this, you flash the current snapshot - then install all needed packages at once.

Not much that you can do than wait (or build the image by yourself).

libubox was updated yesterday and the new version is contained in the firmware images (created by the phase1 buildbot for ath79), but other optional packages (like luci) are compiled separately by the phase2 buildbot (for mips_24kc), and there the new build run is not yet completed, so the known packages list differs from the phase1 results. (depedency list claims an older version of libubox than the one that you already have in the image itself)