Sometimes failure is an option. I am working inside a complex scripting environment. It would be better if when svn update detects a conflict that the update did not occur and that the command would fail. The versioned versions of the file could still be crated and maybe another one that would have the standard conflict markers, but the original file should be unchanged versus copied into the .mine.
The exit code should be non-zero, so it is easy to detect. This new behaviour would only occur with a new option to --accept, I like "--accept failure". Another addition that work with "--accept failure" is if svn update also had --dry-run. Thanks for your considering this feature. Marc Pawlowsky