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by mbp at sourcefrog
import all docs from arch |
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Killing versions |
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**************** |
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Sometimes people really need to rewrite history. The canonical |
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example is that they have accidentally checked confidential |
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information into the wrong tree. |
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There is a tension between two imperatives: |
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* Accurately record all history. |
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* Remove critical information. |
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Of course we cannot control who may have made use of the information |
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in the time it was public, but often these things are caught early enough. |
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After history has been rewritten, anything that depends on that |
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history may be inconsistent. We cannot consistently continue on a |
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version that has had some revisions knocked out; therefore it seems |
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simplest to kill the version over all. |
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You can make a tag onto a new version from a previous consistent |
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revision. |
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Downstream users will need to switch on to the new version. |
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We can mark the version as killed so that mirroring will delete the |
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revisions and clients looking at the version can suggest switching. |
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This should be an extremely infrequent operation so it is OK that it |
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is simple as long as it fulfils the basic requirement. |
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A related problem is that people sometimes commit the wrong log |
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message, or (more seriously) the wrong files. It is common to notice |
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immediately afterwards. |
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Uncommit |
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-------- |
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I think this is the best and most useful option at the moment: the |
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`uncommit command`_ undoes the last commit, and nothing else. It can |
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be repeated to successively remove more and more history. |
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.. _`uncommit command`: cmdref.html#uncommit |
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Example:: |
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% cd my-project |
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% bzr add launch-codes.txt |
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% bzr commit -m 'add launch codes' |
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A launch-codes.txt |
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recorded r23 |
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[oops!] |
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% bzr uncommit |
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[now back to just before the commit command] |
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% bzr status |
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A launch-codes.txt |
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% bzr revert launch-codes.txt |
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% bzr status |
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? launch-codes.txt |
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If anyone else has depended on the option then the branches will have |
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diverged and that needs to be resolved somehow, probably by the other |
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people starting a new branch with the correct commit. In particular |
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uncommitting from a shared branch will break anyone who has seen that |
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revision; possibly there needs to be a policy option on such branches |
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to deny uncommit. |
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If someone else on that shared branch did a the equivalent of a |
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switch_ command then they would bring their changes onto the correct |
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basis. Would it be reasonable to do that automatically? |
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.. _switch: cmdref.html#switch |
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UI proposals |
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------------ |
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Aaron's proposal:: |
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% cd my-project |
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% baz add launch-codes.txt |
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% baz commit -s 'add launch codes' |
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recorded patch-4 |
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% baz add good-code.c |
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% baz commit -s 'add good code' |
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recorded patch-5 |
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[oops!] |
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% baz undo patch-3 |
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% baz pull patch-5 |
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% baz commit --as-latest |
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renamed old branch to my-project-old-1 |
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% baz eradicate my-project-old-1 |
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Long form:: |
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% cd my-project |
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% baz add launch-codes.txt |
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% baz commit -s 'add launch codes' |
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recorded patch-4 |
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% baz add good-code.c |
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% baz commit -s 'add good code' |
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recorded patch-5 |
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[oops!] |
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% cd ../ |
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% baz fork my-project--patch3 my-project-fixed |
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% cd my-project-fixed |
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% baz pull ../my-project patch5 |
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% cd ../ |
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% rm -rf my-project |
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% mv my-project-fixed my-project |
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Robert's proposal:: |
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% cd my-project |
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% baz add launch-codes.txt |
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% baz commit -s 'add launch codes' |
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recorded patch-4 |
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% baz add good-code.c |
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% baz commit -s 'add good code' |
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recorded patch-5 |
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[oops!] |
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% baz branch patch-3 $(baz tree-version) |
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% baz pull . patch-5 |
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% baz eliminate patch-4 |