Part of bzrlib
Testament - a summary of a revision for signing. A testament can be defined as "something that serves as tangible proof or evidence." In bzr we use them to allow people to certify particular revisions as authentic. The goal is that if two revisions are semantically equal, then they will have a byte-for-byte equal testament. We can define different versions of "semantically equal" by using different testament classes; e.g. one that includes or ignores file-ids. We sign a testament rather than the revision XML itself for several reasons. The most important is that the form in which the revision is stored internally is designed for that purpose, and contains information which need not be attested to by the signer. For example the inventory contains the last-changed revision for a file, but this is not necessarily something the user cares to sign. Having unnecessary fields signed makes the signatures brittle when the same revision is stored in different branches or when the format is upgraded. Handling upgrades is another motivation for using testaments separate from the stored revision. We would like to be able to compare a signature generated from an old-format tree to newer tree, or vice versa. This could be done by comparing the revisions but that makes it unclear about exactly what is being compared or not. Different signing keys might indicate different levels of trust; we can in the future extend this to allow signatures indicating not just that a particular version is authentic but that it has other properties. The signature can be applied to either the full testament or to just a hash of it. Testament format 1 ~~~~~~~~~~~~~~~~~~ * timestamps are given as integers to avoid rounding errors * parents given in lexicographical order * indented-text form similar to log; intended to be human readable * paths are given with forward slashes * files are named using paths for ease of comparison/debugging * the testament uses unix line-endings ( )
Class | Testament | Reduced summary of a revision. |
Class | StrictTestament | This testament format is for use as a checksum in bundle format 0.8 |
Class | StrictTestament3 | This testament format is for use as a checksum in bundle format 0.9+ |