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Diffstat (limited to 'doc/design/assistant/transfer_control.mdwn')
| -rw-r--r-- | doc/design/assistant/transfer_control.mdwn | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/doc/design/assistant/transfer_control.mdwn b/doc/design/assistant/transfer_control.mdwn index 070b12246..204f5d090 100644 --- a/doc/design/assistant/transfer_control.mdwn +++ b/doc/design/assistant/transfer_control.mdwn @@ -63,3 +63,21 @@ Some examples of using groups: The above is all well and good for those who enjoy boolean algebra, but how to configure these sorts of expressions in the webapp? + +## the state change problem + +Imagine that a trusted repo has setting like `not copies=trusted:2` +This means that `git annex get --auto` should get files not in 2 trusted +repos. But once it has, the file is in 3 trusted repos, and so `git annex +drop --auto` should drop it again! + +How to fix? Can it even be fixed? Maybe care has to be taken when +writing expressions, to avoid this problem. One that avoids it: +`not (copies=trusted:2 or (in=here and trusted=here and copies=trusted:3))` + +Or, expressions could be automatically rewritten to avoid the problem. + +Or, perhaps simulation could be used to detect the problem. Before +dropping, check the expression. Then simulate that the drop has happened. +Does the expression now make it want to add it? Then don't drop it! +How to implement this simulation? |