[0.18.24] Sync Mods with Save doesn't guarantee replay continuation

[Skibisky]

I had started a save with replay enabled with friends, after trying out some other mods, I pressed 'sync mods with save' to resume it.
After it had finished downloading and restarting there were several unexpected behaviours:

1. A more recent version of a mod was downloaded that was compatible with my basegame (space-exploration 0.3.x, which wanted 0.18.27+)
2. An old version of a disabled mod was *replaced* by an updated version of the mod (the old version was removed from the mods folder).
3. A newer version of the mod was enabled, instead of the version of the mod that was identical to the save.

I was running a save with ~20 mods, but the unexpected behaviour can be demonstrated with the below.

Reproduce:

1. Download 0.18.24 at https://factorio.com/get-download/0.18. ... n64-manual
2. Get space-exploration_0.2.18.zip (and dependencies) from mod website
3. Get alien-biomes 0.5.3
4. Start a game with replay enabled
5. Save game, disable mods, restart
6. Press sync mods with save.
7. Load the save, check that replay saving remains enabled for the save (unlikely).
8. update all mods (space-exp 0.3.x and alien-biomes 0.5.5), then disable them (eg. playing on a different map)
9. Sync mods with original save.
10. Load the save, check that replay saving remains enabled for the save.

Expected behaviour:

Replay recording of the save remains.
The versions of the mods in the sync list are the same as what was in the save.
The enabled/downloaded versions of the mods are compatible with base-game.
No old version of a mod.zip is removed/replaced from mod folder.

Observed behaviour:

Some mods are activated fine (usually because there is no new version)
Mods for which you have several downloaded versions of will activate the latest version, not the version which was originally used in the save.
Mods which are disabled may prompt to download, which will be the latest version, and not guaranteed to be compatible with the current Factorio version.
If the mod gets loaded, replay recording is disabled because of mod/settings mismatch/missing.

Current work-around:

Go through the list of mods+versions in the load window, download the specific version zip from the mod website, add to mod folder manually, manually change version either in UI or mod-list.json

Additional notes:

With space-exploration, 'sync mods with save' would never "finish" because the downloaded version would be instantly disabled because of the incompatible base game, which would then prompt to download a new version...
I would be nice to download specific versions via the in-game mod browser.

[Rseding91]

Thanks for the report. That's all working as intended. The sync functionality doesn't do anything with or care about replays. It simply activates and downloads the latest version of the mod(s) the save was using.