Ideal version control in a production

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I've been thinking what an ideal software version control in a production looks like.

In my opinion an ideal way of version control should satisfy all of these.

a) A software bug fix must be reflected to the work environment automatically.
b) An interface modification of a software must be version controlled and artists must be able to chose which version of the software to use for each project.
c) An artist must be able to open a scene data as it was when it was modified last time. It means softwares (plug-ins etc.) must be the same as what it was including bugs.

I think a) and b) can be solved by defining naming rules carefully referencing this idea. For c) we will need to use a version control system. It'll be good to version control all the softwares in a file server and offer artists, access it through a symbolic link, and offer some utility tool with GUI for artists to retrieve a snapshot of the softwares and change the symbolic link.

Of course I know there are lots of reasons that cannot be simply done, historical reason, human resource, data size, data convert, artist preference, tools/scene data that depend on existing systems, network requirement, and sometimes a boundary between data and tools are not clear ... but it's still important to think about a symple ideal case to get a picture of a good production infrastructure.