[PROPOSAL] Incomplete working copies (issue #695)

I'd like to propose a new solution to this issue, and hopefully
get it into 1.5. What i'm really looking for is the kind of
flexibility Perforce has with its client specs in which parts of
a tree you check out.

I don't think Ben Reser's proposal
(http://svn.haxx.se/dev/archive-2005-07/0398.shtml) covers this.
Using his first example, there is no way to avoid pulling in
trunk/foo/images/another-big-dir when it is added.

This is based on an idea from Karl Fogel.

        Implementing Incomplete Directory Support in SVN
       ==================================================

Many users have very large trees of which they only want to
checkout certain parts. checkout -N is not today up to this
task. This proposal introduces the --depth option to the
checkout, switch, and update subcommands as a replacement for -N,
which allows working copies to have very specific contents,
leaving out everything the user does not want.

This is similar to Perforce's client specs, but without the
ability to have a repository entry have a different name in the
working copy. We actually already have this capability in
switch.

Depth
=====

We have a new "depth" field in .svn/entries, which has three
possible values: 0, 1, or infinity. Only this_dir entries may
have depth:0 or depth:1; all others have depth:inf.

   depth:0 ----------> Updates will not pull in any files or
                        subdirectories not already present.

   depth:1 ----------> Updates will pull in any files or
                        subdirectories not already present; those
                        subdirectories' this_dir entries will
                        have depth:0.

   depth:inf --------> Updates will pull in any files or
                        subdirectories not already present; those
                        subdirectories' this_dir entries will
                        have depth:inf.

The --depth option sets depth values as it updates the working
copy, setting any new subdirectories' this_dir depth values as
described above.

User interface
==============

Affected commands:

    * checkout
    * switch
    * update

The -N option becomes a synonym for --depth 1 for these commands.
This changes the existing -N behavior for these commands, but in
a trivial way (see below).

checkout without --depth or -N behaves the same as it does today.
switch and update without --depth or -N behave the same way as
today IFF the working copy is fully depth:inf. switch and update
without --depth or -N will NOT change depth values (exception: a
missing directory specified on the command line will be pulled
in).

Thus, 'checkout' is identical to 'checkout --depth inf', but
'switch' and 'update' are not the same as 'switch --depth inf'
and 'update --depth inf'. The former update entries according to
existing depth values, while the latter pulls in everything.

To get started, run checkout with --depth 0 or --depth 1. If
additional files or directories are desired, pull them in with
update commands using appropriate --depth options.

Examples
========

svn co http://.../A

    Same as today; everything has depth:inf.

svn co -N http://.../A

    Today, this creates wc containing only mu. Now, this will be
    identical to 'svn co --depth 1 /A'.

svn co --depth 0 http://.../A Awc

    Creates wc Awc, but *empty*.

    Awc/.svn/entries this_dir depth:0

svn co --depth 1 http://.../A Awc1

    Creates wc Awc1 with all files and all subdirectories, but
    subdirectories are *empty*.

    Awc1/.svn/entries this_dir depth:1
                                    B
                                    C
    Awc1/B/.svn/entries this_dir depth:0
    Awc1/C/.svn/entries this_dir depth:0
    ...

svn up Awc/B:

    Since B is not yet checked out, add it at depth infinity.

    Awc/.svn/entries this_dir depth:0
                                    B
    Awc/B/.svn/entries this_dir depth:inf
                                    ...
    Awc/B/E/.svn/entries this_dir depth:inf
                                    ...
    ...

svn up Awc

    Since A is already checked out, don't change its depth, just
    update it. B and everything under it is at depth:inf, so it
    will be updated just as today.

svn up --depth 1 Awc/D

    Since D is not yet checked out, add it at depth 1.

    Awc/.svn/entries this_dir depth:0
                                    B
                                    D
    Awc/D/.svn/entries this_dir depth:1
                                    ...
    Awc/D/G/.svn/entries this_dir depth:0
    ...

svn up --depth 0 Awc/B/E

    Remove everything under E, but leave E as an empty directory
    since B is depth:inf.

    Awc/.svn/entries this_dir depth:0
                                    B
                                    D
    Awc/B/.svn/entries this_dir depth:inf
                                    ...
    Awc/B/E/.svn/entries this_dir depth:0
    ...

svn up --depth 0 Awc/D

    Remove everything under D, and D itself since A is depth:0.

    Awc/.svn/entries this_dir depth:0
                                    B

svn up Awc/D

    Bring D back at depth:inf.

    Awc/.svn/entries this_dir depth:0
                                    ...
    Awc/D/.svn/entries this_dir depth:inf
                                    ...
    ...

svn up --depth 1 Awc

    Bring in everything that's missing (C/ and mu) and empty all
    subdirectories (and set their this_dir to depth:0).

    Awc/.svn/entries this_dir depth:1
                                    B
                                    C
    Awc/B/.svn/entries this_dir depth:0
    Awc/C/.svn/entries this_dir depth:0
    ...

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Received on Fri Jun 23 07:36:44 2006