[0.9.2] Provide better error message when updater fails

[production]

With version 0.9.1, I followed this thread to insert a line in entities.lua: https://forums.factorio.com/forum/vie ... oil#p18268

The updater extracted some files, but quit when it noticed that entities.lua wasn't as expected. The result was an installation where some files were updated, other files were not, and the game wouldn't start at all. I ended up reinstalling the game from scratch.

In the future, before overwriting any files, the updater should check that all files are as expected. And quit *before* overwriting anything if the user has made local changes. If you do this, hopefully in the future your installer won't break a patched but working installation.

[production]

You should be able to reproduce this by installing 0.9.1 (Linux 64-bit), inserting the line in the thread I linked above into entities.lua, and then attempting to update to 0.9.2. The update will be unsuccessful, and if you run the game again, it will fail to start.

[kovarex]

When the source file is different, the update can never work, and although slpwnd suggested to change it, it breaks the updater.
Core files should never be changed, the same change could be achieved by making a small mod instead, so this is not a bug.
(Changed the name of the topic installer->updater)

[sparr]

Even if this isn't supposed to work, it's still a bug that the user is not informed of why the game is broken. At the very least, there should be a dialog that says "update process interrupted due to change in file XXX".

[kovarex]

Even if this isn't supposed to work, it's still a bug that the user is not informed of why the game is broken. At the very least, there should be a dialog that says "update process interrupted due to change in file XXX".

That is true, moving back to bugs

[cube]

In 0.9.4 all update packages will be checked before the update is applied. On windows this means that no updates at all will be performed if a problem is detected, on linux and mac this will work per update (every update is checked before it is applied, but some other updates can be installed before one fails).