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Revision 6 as of 2008-12-24 07:10:07

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Filtered Views


Introducing filtered views

Views provide a mask over the tree so that users can focus on a subset of a tree when doing their work. There are several cases where this masking can be helpful. For example, technical writers and testers on many large projects may prefer to 'see' just the directories/files in the project of interest to them. Developers may also wish to break a large set of changes into 'stages' by using views.

After creating a view, commands that support a list of files - status, diff, commit, etc - effectively have that list of files implicitly given each time. An explicit list of files can still be given to these commands but the nominated files must be within the current view. In contrast, tree-centric commands - pull, merge, update, etc. - continue to operate on the whole tree but only report changes relevant to the current view. In both cases, Bazaar notifies the user each time it uses a view implicitly so that it is clear that the operation or output is being masked accordingly.

The Filtered Views feature is now ready for testing. Please help us get this feature right by:

  • downloading the code
  • reading the draft User Documentation (below)
  • experimenting with it
  • reporting your findings to the mailing list.

To get started, grab the latest code from

Testing setup

Until filtered views are merged into, there are a few things to setup before you can use filtered views. Firstly, be sure you're using a branch of Bazaar that implements filtered views. Secondly, this feature isn't production strength yet so play around in a scratch branch, not your master branch of important code! Thirdly, the default format doesn't support views yet so upgrade your (scratch) branch to 1.12-preview format.

Here's an example of how to get setup for testing this feature on Linux:

  ln -s ~/bzr/repo/bzr.views/bzr ~/bin/bzrfv
  bzrfv branch my-project my-test
  cd my-test
  bzrfv upgrade --1.12-preview

Remaining instructions below will simply refer to bzr so be sure to use bzrfv if that's the script/alias you're using to run the appropriate code.

User documentation

Creating a view

This is done by specifying the files and directories using the view command like this:

  bzr view file1 file2 dir1 ...

The output is:

  Using 'my' view: file1, file2, dir1

Listing the current view

To see the current view, use the view command without arguments:

  bzr view

If no view is current, a message will be output saying No current view.. Otherwise the name and content of the current view will be displayed like this:

  'my' view is: a, b, c

Switching between views

In most cases, a view has a short life-span: it is created to make a selected change and is deleted once that change is committed. At other times, you may wish to create one or more named views and switch between them.

To define a named view and switch to it:

    bzr view --name view-name file1 dir1 ...

For example:

  bzr view --name doc NEWS doc/
  Using 'doc view: NEWS, doc/

To list a named view:

  bzr view --name view-name

To switch to a named view:

  bzr view --switch view-name

To list all views defined:

  bzr view --all

Temporarily disabling a view

To disable the current view without deleting it, you can switch to the pseudo view called off. This can be useful when you need to see the whole tree for an operation or two (e.g. merge) but want to switch back to your view after that.

To disable the current view without deleting it:

  bzr view --switch off

Deleting views

To delete the current view:

  bzr view --delete

To delete a named view:

  bzr view --name view-name --delete

To delete all views:

  bzr view --delete --all

Open Issues

Commit after merge

Selective file commits after a merge aren't (currently) supported by Bazaar, so users need to switch off the view before committing a merge. Perhaps we should explicitly detect that a merge has happened and make bzr commit not implicitly use a view in this case? Or perhaps it still should but only w.r.t. reporting of what gets committed?

File existence

Should we be allowed to create a view containing non-existent files? Right now, no checking is done. Perhaps we should at least produce a warning if a file doesn't exist.

Rename and delete tracking

If the view file contains a list of paths, what happens when things are renamed? Can we trap this and either follow the rename or complain? For example, if a view contains README and doc/ and README gets renamed to README.txt, should the view be implicitly updated?

Likewise, if a file listed in a view is deleted, should the view be implicitly updated?

One option is for the view command to take a --refresh parameter that updates a view definition so that it only contains existing files. It would then be up to the user as to when to do the refreshing.

Design Notes


  • aim for general design useful for both:
    • reduced tree (ala cvs) useful for translators, etc.
    • focussed work (ala git index) useful for breaking large changes into smaller commits
  • provide feedback each time view is being used
  • do lots of tests as we go


1. Store metadata in a new file: .bzr/checkout/view - explicitly doesn't propagate

2. If a view is being invoked, then first message displayed is:

  • Ignoring files outside view: (details of view)

3. If specifying explicit files, error if they are not inside the view.

4. Commands that need to support views include:

  • status
  • diff
  • commit
  • add
  • remove
  • revert
  • mv
  • merge
  • update
  • pull

Some further details are given here: