Version Control with Subversion

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Chapter 7: Advanced Topics

Automatic Property Setting

Properties are a powerful feature of Subversion, acting as key components of many

Subversion features discussed elsewhere in this and other chapters—textual diff and

merge support, keyword substitution, newline translation, etc. But to get the full

benefit of properties, they must be set on the right files and directories. Unfortu-

nately, that can be a step easily forgotten in the routine of things, especially since fail-

ing to set a property doesn’t usually result in an obvious error condition (at least

compared to, say, failing to add a file to version control). To help your properties get

applied to the places that need them, Subversion provides a couple of simple but use-

ful features.

Whenever you introduce a file to version control using the

svn add or svn import

commands, Subversion runs a very basic heuristic to determine if that file consists of

human-readable or non-human-readable content. If the latter is the decision made,

Subversion will automatically set the

svn:mime-type property on that file to

application/octet-stream (the generic this is a collection of bytes MIME type). Of

course, if Subversion guesses incorrectly, or if you wish to set the

svn:mime-type

property to something more precise—perhaps image/png or ...