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Introduction to Bazaar
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======================
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Bazaar's goal is *to make a distributed version control system that
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open source developers will love to use*.  Using Bazaar should feel
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good.
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.. epigraph::
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  Language designers want to design the perfect language. They want to
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  be able to say, "My language is perfect. It can do everything." But
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  it's just plain impossible to design a perfect language, because
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  there are two ways to look at a language. One way is by looking at
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  what can be done with that language. The other is by looking at how
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  we feel using that language -- how we feel while programming.
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  Because of the Turing completeness theory, everything one
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  Turing-complete language can do can theoretically be done by another
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  Turing-complete language, but at a different cost. You can do
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  everything in assembler, but no one wants to program in assembler
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  anymore. From the viewpoint of what you can do, therefore, languages
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  do differ -- but the differences are limited. For example, Python
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  and Ruby provide almost the same power to the programmer.
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  Instead of emphasizing the what, I want to emphasize the how part: how
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  we feel while programming.
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  -- `Yukihiro Matsumoto`__
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__ http://www.artima.com/intv/ruby.html
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Bazaar tries to make simple things simple, and complex things
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possible.  In particular:
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 * Distributed operation is easy: you can work while disconnected; you
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   can fork any other project; you can contribute changes back
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   easily.  
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 * The system is designed to scale to supporting very large trees with
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   a lot of history.  No operations require downloading the entire
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   history of the project.
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 * Changes can be "cherry-picked" out of branches as needed.   Because
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   of dependencies between 
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History-sensitive merging
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=========================
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Baz keeps track of what changes have been merged into a branch.  You
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can repeatedly merge from one branch into another and Baz will pull
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across only the new changes since you last merged.
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Speed
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=====
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For most users, the most important factor for performance is to avoid
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unnecessary network round trips.  Baz tries hard to avoid ever
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downloading the same data twice.  
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Remote archives are automatically cached on your local machine by
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default.  If you have ever accessed a remote revision you should be
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able to get it again without going to the network.  The cache policy
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may be tuned.
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Code history
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============
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One important function of a revision control system is to maintain a
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record of when, why, how and by whom changes were made. 
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Baz requires that branches and archives be named.
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Unlike most other systems, Baz keeps a record for each changeset of
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which branches and archives it passed through on its way to its
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eventual destination.  This allows people to go back later and see the
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context in which the patch was written or merged.
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Scalability
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===========
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We regularly test Baz on projects with tens of thousands of commits,
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and tens of thousands of files.
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Merging
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=======
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The basic method of integration is a three-way merge.  Baz selects an
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appropriate basis version
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File renaming
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=============
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Baz allows files and directories to be renamed in a project.  Unlike
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Subversion, Baz will correctly merge changes spanning file renames.
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This is done by automatically assigning a unique ID to each file,
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which is persistent across renames.
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