# Tailor 1.0

Contents

- About
- Installation
- Testing
- Operation
  - Examples
  - CVS start-revision
- Resolving conflicts
- Shortcomings
- Config file format
  - Configuration sections
    - Default
    - Projects
    - Repositories
      - Common options
      - aegis
      - arx
      - baz
      - bzr
      - cdv
      - cvs
      - cvsps
      - darcs
        - Big repositories
      - git target
      - hg
      - monotone
      - p4
      - svn
      - tla
  - Disjunct working directories
  - Using a Python script as configuration file
    - Pre-commit and post-commit hooks
      - Example 1
      - Example 2
      - Example 3
  - State file
  - Logging
- Further help
- Authors
  - Aegis support
  - ArX support
  - Bazaar support
  - Git support
  - Monotone support
  - Perforce support
  - Tla support
- License
- About this document

# About

Tailor is a tool to migrate changesets between Aegis, ArX, Baz, Bazaar, CVS, Codeville, Darcs, Git, Mercurial, Monotone, Perforce, Subversion and Tla [1] repositories.

This script makes it easier to keep the upstream changes merged in a branch of a product, storing needed information such as the upstream URI and revision in special properties on the branched directory.

The following ascii-art illustrates the usual scenario:

                             +------------+            +------------+
    +--------------+         | Immutable  |            | Working    |
    | Upstream CVS |-------->| darcs      |----------->| darcs      |
    | repository   | tailor  | repository | darcs pull | repository |
    +--------------+         +------------+            +------------+
                                                             |^
                                                             ||
                                                             ||
                                                             v|
                                                            User

Ideally you should be able to swap and replace "CVS server" and "darcs repository" with any combination of the supported systems.

It's still lacks the ability of doing a two way sync.

[1] | Aegis, ArX and Codeville systems may be used only as the target backend, since the source support isn't coded yet. Contributions on these backends will be very appreciated, since I do not use them enough to figure out the best way to get pending changes and build tailor ChangeSets out of them. To the opposite, Baz (1.0, not Bazaar), Perforce and Tla are supported only as source systems.

# Installation

tailor is written in Python, and thus Python must be installed on your system to use it. It has been successfully used with Python 2.3, 2.4 and 2.5.

Since it relies on external tools to do the real work such as cvs, darcs [2] and svn, they need to be installed as well, although only those you will actually use.

Make tailor executable:

    $ chmod +x tailor

You can either run tailor where it is currently located, or move it along with the vcpx directory to a location in your PATH.

There's even a standard setup.py that you may use to install the script using Python's conventional distutils.

[2] | Darcs 1.0.2 is too old, 1.0.3 is good, 1.0.4 (the fourth release candidate is under final testing) is recommended since it's faster in most operations!

# Testing

Tailor has more than 50 unit and operational tests, that you can run with the following command line:

    $ tailor test -v

Since some tests take very long to complete, in particular the operational tests, you may prefer the execution of a single suite:

    $ tailor test -v Darcs

or even a single test within a suite:

    $ tailor test StateFile.testJournal

To obtain a list of the test, use `--list` option. As usual with:

    $ tailor test --help

you will get some more details.

More recently, a suite of functional tests was added, in the directory `./test-scripts`: these are simple shell scripts that basically build a source repository, create a configuration file and run tailor, checking the result. You can execute them with:

    $ sh test-svn2svn-simple.sh

or:

    $ sh run-all-test.sh

# Operation

tailor needs now a configuration file that collects the various bits of information it needs to do its job.

The simplest way of starting out a new configuration is by omitting the `--configfile` command line option, and specifying the other as needed plus `--verbose`: in this situation, tailor will print out an equivalent configuration that you can redirect to a file, that you later will pass as `--configfile` (or simply `-c`).

## Examples

1. Bootstrap a new tailored project, starting at upstream revision 10

   1. First create a config file:

          $ tailor --verbose -s svn -R http://svn.server/path/to/svnrepo \
                   --module /Product/trunk -r 10 --subdir Product \
                   ~/darcs/MyProduct > myproject.tailor

   2. Modify it as you like (mostly adjusting root-directories and the like):

          $ emacs myproject.tailor

   3. Run tailor on it:

          $ tailor --configfile myproject.tailor

2. Bootstrap a new product, fetching its whole CVS repository and storing under SVN

   1. First create a config file:

          $ tailor --verbose --source-kind cvs --target-kind svn \
                   --repository :pserver:cvs.zope.org:/cvs-repository \
                   --module CMF/CMFCore --revision INITIAL \
                   --target-repository file:///some/where/svnrepo \
                   --target-module / cmfcore > cmfcore.tailor

   2. Modify it as you like (mostly adjusting root-directories and the like):

          $ emacs cmfcore.tailor

   Note

   By default, tailor uses "." as `subdir`, to mean that it will extract upstream source directly inside the `root-directory`.

   This is known to cause problems with CVS as source, with which you could see some wierd error like

       $ cvs -q -d ...:/cvsroot/mymodule checkout -d . ... mymodule
       cvs checkout: existing repository /cvsroot/mymodule does not match /cvsroot/mymodule/mymodule
       cvs checkout: ignoring module mymodule

   When this is the case, the culprit may be a CVS shortcoming not being able to handle `-d .` in the right way. Specify a different `subdir` option to avoid the problem.

   3. Run tailor on it once, to bootstrap the project:

          $ tailor -D -v -c cmfcore.tailor

      If the target repository is on the local filesystem (ie, it starts with `file:///`) and it does not exist, tailor creates a new empty Subversion repository at the specified location.

   Note

   Before step d) below, you may want to install an appropriate hook in the repository to enable the propset command to operate on unversioned properties, as described in the svn manual. Then you can specify '--use-propset' option, and tailor will put the original author and timestamp in the proper svn metadata instead of appending them to the changelog.

   Other than the annoying repository manual intervention, this thread and this other explain why using `-r{DATE}` may produce strange results with this setup.

   4. Run tailor again and again, to sync up with latest changes:

          $ tailor -v --configfile cmfcore.tailor

3. Given the configuration file shown below in Config file format, the following command:

       $ tailor --configfile example.tailor

   is equivalent to this one:

       $ tailor --configfile example.tailor tailor

   in that they operate respectively on the default project(s) or the ones specified on the command line (and in this case there is just a single default project, tailor).

   This one instead:

       $ tailor -c example.tailor tailor tailor-reverse

   operates on both projects.

## CVS start-revision

With CVS, you can specify a particular point in time specifying a start-revision with a timestamp like `2001-12-25 23:26:48 UTC`.

To specify also a particular branch, prepend it before the timestamp, as in `unstable-branch 2001-12-25 23:26:48 UTC`.

To migrate the whole history of a specific branch, use something like `somebranch INITIAL`.

# Resolving conflicts

Should one of the replayed changes generate any conflict, tailor will prompt the user to correct them. This is done after the upstream patch has been applied and before the final commit on the target system, so that manually tweaking the conflict can produce a clean patch.

# Shortcomings

Tailor currently suffers of the following reported problems:

1. It does not handle "empty" CVS checkouts, in other words you cannot bootstrap a project that has nothing in its CVS upstream repository, or from a point in time where this condition was true.
2. It's completely unsupported under Windows, evenif it now uses 2.4's subprocess that seems able to hide Windows crazyness...
3. ArX and Codeville are (currently) only supported as target; Baz and Tla only as source.
4. Specifying `--subdir .` may not work, in particular when dealing with remote CVS repositories (it does when the CVS repository is on local machine).

This list will always be incomplete, but I'll do my best to keep it short :-)

# Config file format

When your project is composed by multiple upstream modules, it is easier to collect such information in a single file. This is done by specifying the --configfile option with a file name as argument. In this case, tailor will read the above information from a standard Python ConfigParser file.

For example:

    [DEFAULT]
    verbose = True
    projects = tailor

    [tailor]
    root-directory = /tmp/n9
    source = darcs:tailor
    target = svn:tailor
    state-file = tailor.state

    [tailor-reverse]
    root-directory = /tmp/n9
    source = svn:tailor
    target = darcs:tailor
    state-file = reverse.state

    [svn:tailor]
    repository = file:///tmp/testtai
    module = /project1
    subdir = svnside

    [darcs:tailor]
    repository = ~/WiP/cvsync
    subdir = darcside

The configuration may hold one or more projects and two or more repositories: project names do not contains colons ":", repository names must and the first part of the name before the colon specify the kind of the repository. So, the above example contains two projects, one that goes from darcs to subversion, the other in the opposite direction.

The `[DEFAULT]` section contains the default values, that will be used when a specific setting is missing from the particular section.

You can specify on which project tailor should operate by giving its name on the command line, even more than one. When not explicitly given, tailor will look at `projects` in the `[DEFAULT]` section, and if its missing it will loop over all projects in the configuration.

The following simpler config just go in one direction, for a single project, so no need neither for `[DEFAULT].projects` nor command line arguments. Also, notice the usage of the repository short cut: the `source` and `target` will be implicitly loaded from cvs:pxlib and hg:pxlib respectively:

    [pxlib]
    source = cvs:
    target = hg:
    root-directory = ~/mypxlib
    start-revision = INITIAL
    subdir = pxlib

    [cvs:pxlib]
    repository = :pserver:anonymous@cvs.sf.net:/cvsroot/pxlib
    module = pxlib

    [hg:pxlib]

This will use a single directory, `pxlib` to contain both the source and the target system. If you prefer keeping them separated, you just need to specify a different directory for each repository [3], as in:

    [pxlib]
    source = cvs:pxlib
    target = hg:pxlib
    root-directory = ~/mypxlib
    start-revision = INITIAL

    [cvs:pxlib]
    repository = :pserver:anonymous@cvs.sf.net:/cvsroot/pxlib
    module = pxlib
    subdir = original
    delay-before-apply = 10

    [hg:pxlib]
    subdir = migrated

This will extract upstream CVS sources into `~/mypxlib/original`, and create a new Mercurial repository in `~/mypxlib/migrated`.

The following example shows the syntax of Baz sources:

    [project]
    target = hg:target
    start-revision = base-0
    root-directory = /tmp/calife
    state-file = hidden
    source = baz:source

    [baz:source]
    module = calife--pam--3.0
    repository = roberto@keltia.net--2003-depot
    subdir = tla

    [hg:target]
    repository = /tmp/HG/calife-pam
    subdir = hg

Note the usage of `hidden` for the state file name: given the importance of this file, that at the same time is of no interest by the user, this will store that information inside the same directory used by the target repository for its metadata, with the name `tailor.state`. In this particular example, it will end up as `/tmp/calife/hg/.hg/tailor.state`.

Last, a complete example used to migrate the whole Monotone source repository under Subversion:

    [DEFAULT]
    #debug = True
    #verbose = True
    start-revision = INITIAL
    root-directory = /tmp/rootdir-Monotone
    source = monotone:
    target = svn:
    source-repository = /home/user/Monotone/monotone-database.mtn
    target-repository = file:///tmp/svn-repository
    use-propset = True

    # Projects
    [net.venge.monotone.cvssync]

    [net.venge.monotone.cvssync.attrs]

    [net.venge.monotone.de]

    [net.venge.monotone.svn_import]

    [net.venge.monotone]

    # Sources
    [monotone:net.venge.monotone.cvssync]
    module = net.venge.monotone.cvssync
    subdir = mtnside-net.venge.monotone.cvssync

    [monotone:net.venge.monotone.cvssync.attrs]
    module = net.venge.monotone.cvssync.attrs
    subdir = mtnside-net.venge.monotone.cvssync.attrs

    [monotone:net.venge.monotone.de]
    module = net.venge.monotone.de
    subdir = mtnside-net.venge.monotone.de

    [monotone:net.venge.monotone.svn_import]
    module = net.venge.monotone.svn_import
    subdir = mtnside-net.venge.monotone.svn_import

    [monotone:net.venge.monotone]
    module = net.venge.monotone
    subdir = mtnside-net.venge.monotone

    # Targets
    [svn:net.venge.monotone.cvssync]
    module = branches/net.venge.monotone.cvssync
    subdir = svnside-net.venge.monotone.cvssync

    [svn:net.venge.monotone.cvssync.attrs]
    module = branches/net.venge.monotone.cvssync.attrs
    subdir = svnside-net.venge.monotone.cvssync.attrs

    [svn:net.venge.monotone.de]
    module = branches/net.venge.monotone.de
    subdir = svnside-net.venge.monotone.de

    [svn:net.venge.monotone.svn_import]
    module = branches/net.venge.monotone.svn_import
    subdir = svnside-net.venge.monotone.svn_import

    [svn:net.venge.monotone]
    module = trunk
    subdir = svnside-net.venge.monotone

[3] | NB: when the source and the target repositories specify different directories with the `subdir` option, tailor uses `rsync` to keep them in sync, so that tool needs to be installed.

## Configuration sections

### Default

The `[DEFAULT]` section in the configuration file may set the default value for any of the recognized options: when a value is missing from a specific section it is looked up in this section.

One particular option, `projects`, is meaningful only in the `[DEFAULT]` section: it's a comma separated list of project names, the one that will be operated on by tailor when no project is specified on the command line. When the there are no `projects` setting nor any on the command line, tailor activates all configured projects, in order of appearance in the config file.

### Projects

A project is identified by a section whose name does not contain any colon (":") character, and configured with the following values:

Note

If a particular option is missing from the project section, its value is obtained looking up the same option in the `[DEFAULT]` section.

root-directory : string
  This is where all the fun will happen: this directory will contain the source and the target working copy, and usually the state and the log file. It supports the conventional ~user to indicate user's home directory and defaults to the current working directory.
subdir : string
  This is the subdirectory, relative to the root-directory, where tailor will extract the source working copy. It may be '.' for some backend kinds. The source and target backends will use this value if they don't explicitly override it.
state-file : string
  Name of the state file needed to store tailor last activity. When this is set to `hidden`, the state file will be named `tailor.state`, possibly under the target's `METADIR`.
source : string
  The source repository: a repository name is something like "darcs:somename", that will be loaded from the homonymous section in the configuration. As a short cut, the "somename" part may be omitted: in that case, the project name will be appended to the specified prefix.
target : string
  The counterpart of source, the repository that will receive the changes coming from there.

Non mandatory options:

verbose : bool
  Print the commands as they are executed.
debug : bool
  Print also their output.
before-commit : tuple
  This is a function name, or a sequence of function names enclosed by brackets, that will be executed on each changeset just before it get replayed on the target system: this may be used to perform any kind of alteration on the content of the changeset, or to skip some of them.
after-commit : tuple
  This is a function name, or a sequence of function names enclosed by brackets, that will be executed on each changeset just after the commit on the target system: this may be used for example to create a tag.
subdir : string
  The name of the subdirectory, under `root-directory`, that will contain the source and target repositories/working directories.
start-revision : string
  This identifies from when tailor should start the migration. It can be either `INITIAL`, to indicate the start of the history, or `HEAD` to indicate the current latest changeset, or a backend specific way of indicate a particular revision/tag in the history. See also CVS start-revision above.
patch-name-format : string

  Some backends have a distinct notion of patch name and change log, others just suggest a policy that the first line of the message is a summary, the rest if present is a more detailed description of the change. With this option you can control the format of the name, or of the first line of the changelog.

  The prototype may contain `%(keyword)s` such as 'author', 'date', 'revision', 'firstlogline', 'remaininglog' or 'project'. It defaults to `[%(project)s @ %(revision)s]` [4].

  When you set it empty, as in

      [project]
      patch-name-format = ""

  tailor will keep the original changelog as is.

remove-first-log-line : bool

  Remove the first line of the upstream changelog. This is intended to go in pair with `patch-name-format`, when using its 'firstlogline' variable to build the name of the patch. The default is `False`.

  A reasonable usage is:

      [DEFAULT]
      patch-name-format=[%(project)s @ %(revision)s]: %(firstlogline)s
      remove-first-log-line=True

refill-changelogs : bool
  Off by default, when active tailor reformats every changelog before committing on the target system.

[4]

Modifying the changelog may have subtle consequences! Under darcs, for example, you may hit issue772 by producing hash collisions, that happens when two distinct patches carry the same "unique" identifier (the hash is computed using date, author, changelog and other details, but not the actual content): the default setting, that adds a differentiating prefix, is safer from that point of view.

### Repositories

All the section whose name contains at least one colon character denote a repository. A single repository may be shared by zero, one or more projects. The first part of the name up to the first colon indicates the kind of the repository, one of `aegis`, `arx`, `baz`, `bzr`, `cdv`, `cvs`, `darcs`, `git`, `hg`, `monotone`, `p4`,``svn`` and `tla`.

Note

If a particular option is missing from the repository section, its value is obtained looking up the same option in the section of the project currently using the repository, falling back to the `[DEFAULT]` section.

Some options may be shared with others repositories, like in the following example, where the common settings for the target monotone repository are set just once:

    [DEFAULT]
    target-repository = /bigdisk/my-huge-repository.mtn
    target-keyid = test@example.com
    target-passphrase = lala
    source-repository = http://svn.someserver.com

    [productA]
    target = monotone:productA
    source = svn:sourceA

    [productB]
    target = monotone:productB
    source = darcs:sourceB

    [productC]
    target = monotone:productC
    source = svn:sourceC

    [productC_darcs]
    target = darcs:
    source = svn:sourceC

    ...

    [monotone:productA]
    module = every.thing.productA

    [monotone:productB]
    module = every.thing.productB

    [monotone:productC]
    module = every.thing.productC

    [svn:sourceA]
    module = /productA

    [darcs:sourceB]
    repository = http://some.server.com/darcs/productB

    [svn:sourceC]
    module = /productC

For some backends, for example for those that like `darcs` do not make a distinction between repository and working copy and thus the former may be assumed by `root-directory` (and possibly `subdir`), the config section may be completely omitted, as done for productC_darcs above.

#### Common options

repository : string
  When a repository is used as a source, it must indicate its origin with `repository`, and for some backends also a `module`, but are not required when it's a target system, even if some backend may use the information to create the target repository (like `svn` backend does).
subdir : string

  When the source and target repositories use different subdirectories, tailor uses `rsync` to copy the changes between the two after each applied changeset. When the source repository basedir is a subdirectory of target basedir tailor prefixes all paths coming from upstream to match the relative position.

  This defaults to the project's setting.

command : string
  Backends based on external command line tool such as svn or darcs offers this option to impose a particular external binary to be used, as done below in the example about disjunct working directories.
python-path : string
  For pythonique backends such as bzr and hg this indicates where the respective library is located.
encoding : string

  States the charset encoding the particular repository uses, and it's particularly important when it differs from local system setup, that you may inspect executing:

      python -m locale

encoding-errors-policy : string
  By default is strict, that means that Python will raise an exception on Unicode conversion errors. Valid options are ignore that simply skips offending glyphs and replace where unrecognized entities are replaced with a place holder.
delay-before-apply : integer

  Sometime the migration is fast enough to put the upstream server under an excessive load. When this is the case, you may specify `delay-before-apply = 5`, that is the number of seconds tailor will wait before applying each changeset.

  It defaults to None, ie no delay at all.

post-commit-check : bool

  After each commit tailor will perform a check on the target working directory asserting there's no changes left. This is particularly useful when trying to debug source backends... at a little cost.

  True by default.

#### aegis

Sample config fragment:

    [aegis:target]
    #
    # Set the aegis project as the tailor module, tailor will *not*
    # create the aegis project for you!
    #
    module = $AEGIS_PROJECT
    #
    # the subdir will be used as the working directory for aegis
    # changes, it *must* be different from the source:subdir.
    #
    subdir = aegisside

#### arx

#### baz

#### bzr

#### cdv

#### cvs

changeset-threshold : integer

  Maximum number of seconds allowed to separated commits to different files for them to be considered part of the same changeset.

  180 by default.

freeze-keywords : bool

  With this enabled (it is off by default) tailor will use `-kk` flag on checkouts and updates to turn off the keyword expansion. This may help minimizing the chance of spurious conflicts with later merges between different branches.

  False by default.

tag-entries : bool

  CVS and CVSPS repositories may turn off automatic tagging of entries, that tailor does by default to prevent manual interventions in the CVS working copy, using `tag_entries = False`.

  True by default.

trim-module-components : integer

  When the checked out tree involves CVS modules on the server Tailor fails to build up the ChangeSets view from the `cvs rlog` output, since in that case the paths that Tailor finds in the log refers to the real location of the entries on the server, and not, as usual, relatives to the root of the checked out tree. Of course, Tailor must be exact in correlating the information coming from the log and the actual checked out content in the filesystem, so in this case, by default it fails with an obscure message at bootstrap time.

  Given that most of the time it's simply a matter of a common prefix, this option offers the so called "far-from-perfect-poor-man-workaround" to the CVS/Tailor shortcoming, until a better solution arises.

  When you set this to an integer greater than zero, the parser will cut off that many components from the beginning of the pathnames it finds in the log.

  0 (zero) by default.

#### cvsps

freeze-keywords : bool

  With this enabled (it is off by default) tailor will use `-kk` flag on checkouts and updates to turn off the keyword expansion. This may help minimizing the chance of spurious conflicts with later merges between different branches.

  False by default.

tag-entries : bool

  CVS and CVSPS repositories may turn off automatic tagging of entries, that tailor does by default to prevent manual interventions in the CVS working copy, using `tag_entries = False`.

  True by default.

#### darcs

init-options : string
  By default empty, may specify options used to initialize the target repository, for example to use the newer `darcs-2`.
look-for-adds : bool
  By default tailor commits only the entries explicitly mentioned by the upstream changeset. Sometimes this is not desiderable, maybe even as a quick workaround to a tailor bug. This option allows a more relaxed view of life using `record --look-for-adds`.
replace-badchars : string

  Apparently some darcs repo contains some characters that are illegal in an XML stream. This is the case when one uses non-utf8 accents. To be safe, you can replace them with their xml-safe equivalent. The given string must be a regular and valid Python dictionary, with each substitution keyed on the character to be replaced. By default it's:

      {
        '\xc1': '&#193;',
        '\xc9': '&#201;',
        '\xcd': '&#205;',
        '\xd3': '&#211;',
        '\xd6': '&#214;',
        '\xd5': '&#336;',
        '\xda': '&#218;',
        '\xdc': '&#220;',
        '\xdb': '&#368;',
        '\xe1': '&#225;',
        '\xe9': '&#233;',
        '\xed': '&#237;',
        '\xf3': '&#243;',
        '\xf6': '&#246;',
        '\xf5': '&#337;',
        '\xfa': '&#250;',
        '\xfc': '&#252;',
        '\xfb': '&#369;',
        '\xf1': '&#241;',
        '\xdf': '&#223;',
        '\xe5': '&#229;'
      }

start-revision : string

  Under darcs this may be either the name of a tag or the hash of an arbitrary patch in the repository, plus the ordinary `INITIAL` or `HEAD` symbols.

  Note

  If you want to start from a particular patch, giving its hash value as `start-revision`, you must use a `subdir` different from `"."`. [5]

split-initial-changeset-level : integer

  Sometime it's desiderable to avoid the impact of the huge patch produced by the bootstrap step, that's basically a snapshot of the whole working directory. This option controls that: if greater than zero, the initial import will be splitted in multiple changesets, one per directory not deeper than the specified level. A value of 1 will build a changeset for the top level contents (directories and files), then a changeset for each subtree. Finally, a tag will comprehend all the changesets.

  0 by default.

##### Big repositories

To migrate a big darcs repository it is faster doing a chunked approach, that is using an intermediary repository where you pull say a couple of hundreds patches at a time from the real source repository, and then run tailor, in a loop. The following script illustrates the method:

    mkdir /tmp/intermediary-repo
    cd /tmp/intermediary-repo
    darcs init --darcs-2
    while python -c "print 'y'*200+'d'" | darcs pull --quiet real-source-repo
    do
      tailor -c from-intermediary.tailor
    done

When darcs is the target, consider setting a value of 1 or even 2 for the option split-initial-changeset-level.

#### git target

parent-repo : string

  Relative path to a git directory to use as a parent. This is one way to import branches into a git repository, which creates a new git repository borrowing ancestry from the parent-repo. It is quite a simple way, and thus believed to be quite robust, but spreads branches across several git repositories. If this parameter is not set, and `repository` is not set either, the branch has no parent.

  The alternative is to specify a `repository` parameter, to contain all git branches. The .git directory in the working copy for each branch will then only contain the `.git/index` file.

branch : string
  The name of the branch to which to commit. It is only used in single-repository mode (using `repository`, see above). The default is to use the "master" branch.
branchpoint : string

  A reference to the git commit which is the parent for the first revision on the branch to be imported. It can be a tag name or any syntax acceptable by git (eg. something like "tag~2", if you want to correct the idea of where the branchpoint is).

  Since tailor generates mostly-stable SHA-1 revisions, you can usually also use a SHA-1 as branchpoint. Just import your trunk first, find the correct SHA-1, and setup and import your branch. This is especially useful since the current cvs source implementation misses many tags.

overwrite-tags : bool

  By default the backend does not overwrite previous tag with a newer by the same name, and stops with an error. This flag allows you to force git to override preceeding tag with the same name.

  False by default.

#### hg

#### monotone

keyid : string
  Monotone key id to use for commits. The specified key must exist on keystore. Takes precedence over keygenid.
keygenid : string
  Id of a new keypair to generate and store in the repository. The keypair is used for commits. Ignored if keyid is specified.
passphrase : string
  Passphrase to use for commits. Must be specified unless you have one on your .monotonerc file
custom-lua : string
  Optional custom lua script. If present, is written into _MTN/monotonerc.

#### p4

depot-path : string

  The path within the depot indicating the root of all files that will be replicated.

  This is used both for determining changes as well as mapping file locations from changesets to the filesystem.

  Example: `//depot/project/main/`

p4-client : string

  The perforce client spec to use.

  Example: `myhostname-tailor`

p4-port : string

  The address of the perforce server.

  Example: `perforce.mycompany.com:1666`

#### svn

filter-badchars : bool (or string)

  Activate (with True) or activate and specify (with a string) the filter on the svn log to eliminate illegal XML characters.

  False by default, when set to True the following characters are washed out from the upstream changes:

      allbadchars = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09" \
                    "\x0B\x0C\x0E\x0F\x10\x11\x12\x13\x14\x15" \
                    "\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F\x7f"

  If this is not right or enough, you can specify a string value instead of the boolean flag, containing the characters to omit, as in:

      filter-badchars=\x00\x01

use-propset : bool

  Indicate that tailor is allowed to properly inject the upstream changeset's author and timestamp into the target repository. As stated above, this requires a manual intervention on the repository itself and thus is off by default, and tailor simply appends those values to the changelog. When active at bootstrap time and the repository is local, tailor creates automatically a minimal `hooks/pre-revprop-change` script inside the repository, so no other intervention is needed.

  False by default.

propset-date : bool
  By default True, can be used to avoid setting the `svn:date` property on the Subversion revision, and thus problem with `-r{DATE}` mentioned above. When this is False, the original timestamp gets appended to the revision log.
use-limit : bool
  By default True, should be set to False when using old Subversion clients, since `log --limit` was introduced with version 1.2. By using this option tailor can fetch just the revision it needs, instead of transfering whole history log.
commit-all-files : bool
  By default True, commits all files from current changeset. Lets Subversion check the changes self. Set it to False, then whish to commits only changed files, that tailor detects, perhaps a network speedup. But a False can be insert an extra revision on long dep paths with lot of files. You would see two revisions on target, where the source have only one. For a true convert should leave it True.
trust-root : bool
  Tailor by default verifies that the specified `repository` effectively points to the root of a Subversion repository, eventually splitting it and adjusting `module` accordingly. This is sometimes undesiderable, for example when the root isn't public and cannot be listed. Setting this option to True disable the check and tailor takes the given `repository` and `module` as-is.
ignore-externals : bool
  By default the Subversion backend does not consider the external references defined in the source repository. This option force Tailor to behave as it did up to 0.9.20.
svn-tags : string

  Name of the directory used for tags: tailor will copy tagged revisions under this directory.

  `/tags` by default.

svn-branches : string

  Name of the directory used for branches: tailor will copy branches under that directory.

  `/branches` by default.

  Note

  Target module for branches must start with `branches/`. Every branch must configure in a single-repository mode.

  Example: `module = branches/branch.name`

#### tla

[5] | This is because when you use `subdir = .` tailor uses `darcs pull` instead of `darcs get`, and the former does not accept the option `--to-match`.

## Disjunct working directories

A particular case happens when the `subdir` specified in the source is different from the one in target as in:

    [tailor-d1-to-d2]
    patch-name-format = ''
    source = darcs:source
    target = darcs:target
    start-revision = INITIAL

    [darcs:source]
    repository = http://darcs.arstecnica.it/tailor
    subdir = tailor_d1

    [darcs:target]
    darcs-command = /usr/local/bin/darcs2
    init-options = --darcs-2
    subdir = tailor_d2

In this particular case, the kind may be the same, allowing particular migrations between the same kind of VC, as showed.

Tailor will use `rsync` to move the changes applied in the source subdirectory to the target one.

## Using a Python script as configuration file

Instead of executing `tailor --configfile project.tailor.conf` you can prepend the following signature to the config itself:

    #!/usr/bin/env /path/to/tailor

Giving execute mode to it will permit the launch of the tailor process by running the config script directly:

    $ ./project.tailor.conf

When a config file is signed in this way [6], either you pass it as argument to `--configfile` or executed as above, tailor will actually execute it as a full fledged Python script, that may define functions that alter the behaviour of tailor itself.

### Pre-commit and post-commit hooks

A common usage of this functionality is to define so called hooks, sequences of functions that are executed at particular points in the tailorization process.

#### Example 1

Just to illustrate the functionality, consider the following example:

    #!/usr/bin/env tailor

    """
    [DEFAULT]
    debug = False
    verbose = True

    [project]
    target = bzr:target
    root-directory = /tmp/prova
    state-file = tailor.state
    source = darcs:source
    before-commit = before
    after-commit = after
    start-revision = Almost arbitrarily tagging this as version 0.8

    [bzr:target]
    python-path = /opt/src/bzr.dev
    subdir = bzrside

    [darcs:source]
    repository = /home/lele/WiP/cvsync
    subdir = darcside
    """

    def before(wd, changeset):
        print "BEFORE", changeset
        changeset.author = "LELE"
        return changeset

    def after(wd, changeset):
        print "AFTER", changeset

With the above in a script called say `tester`, just doing:

    $ chmod 755 tester
    $ ./tester

will migrate the history from a darcs repository to a Bazaar one, forcing the author to a well-known name :-)

#### Example 2

A pre commit hook may even alter the content of the files. The following function replaces the DOS end-of-line convention with the UNIX one:

    def newlinefix(wd, changeset):
        from pyutil import lineutil
        lineutil.lineify_all_files(wd.basedir, strip=True,
                                   dirpruner=lineutil.darcs_metadir_dirpruner,
                                   filepruner=lineutil.source_code_filepruner)
        return True

It uses zooko's pyutil [7] toolset. Another approach would be looping over changeset.entries and operating only on added or changed entries.

#### Example 3

This loops over the file touched by a particular changeset and tries to reindent it if it's a Python file:

    def reindent_em(wd, changeset):
        import reindent
        import os

        for entry in changeset.entries:
            fname = os.path.join(wd.basedir, entry.name)

            try:
                if fname[-3:] == '.py':
                    reindent.check(fname)
            except Exception, le:
                print "got an exception from attempt to reindent" \
                      " (maybe that file wasn't Python code?):" \
                      " changeset entry: %s, exception:" \
                      " %s %s %s" % (entry, type(le), repr(le),
                                     hasattr(le, 'args') and le.args,)
                raise le
        return True

You have to find reindent.py in your Python distribution and put it in your python path. Beware that this has some drawbacks: be sure to read ticket 8 annotations if you use it.

[6] | Tailor does actually read just the first two bytes from the file, and compare them with "#!", so you are free to choose whatever syntax works in your environment.

[7] | Available either at https://yumyum.zooko.com:19144/pub/repos/pyutil or http://zooko.com/repos/pyutil.

## State file

The state file stores two things: the last upstream revision that has been applied to the tree, and a sequence of pending (not yet applied) changesets, that may be empty. In the latter case, tailor will fetch latest changes from the upstream repository.

## Logging

Tailor uses the Python's logging module to emit noise. Its basic configuration is hardwired and corresponds to the following:

    [formatters]
    keys = console

    [formatter_console]
    format =  %(asctime)s [%(levelname).1s] %(message)s
    datefmt = %H:%M:%S

    [loggers]
    keys = root

    [logger_root]
    level = INFO
    handlers = console

    [handlers]
    keys = console

    [handler_console]
    class = StreamHandler
    formatter = console
    args = (sys.stdout,)
    level = INFO

Another handler is added at runtime that appends any message in a file named `projectname.log` inside the root directory. This file contains much more details than those usually reaching the console, and may be of some help to understand what went wrong.

However, you can completely override the default adding a supersection `[[logging]]` to the configuration file, something like:

    # ... usual tailor config ...
    [project]
    source = bzr:source
    target = hg:target

    # Here ends tailor config, and start the one for the logging
    # module

    [[logging]]

    [logger_tailor.BzrRepository]
    level = DEBUG
    handlers = tailor.source

    [handler_tailor.source]
    class = SMTPHandler
    args = ('localhost', 'from@abc', ['tailor@abc'], 'Tailor log')

# Further help

See the output of `tailor -h` for some further tips. The official documentation is available as a set of wiki pages managed by a Trac instance, but there is also this page on the Darcs wiki that may give you some other hints.

The development of Tailor is mainly driven by user requests at this point, and the preferred comunication medium is the dedicated mailing list [8].

I will be more than happy to answer any doubt, question or suggestion you may have on it. I'm usually hanging out as "lelit" on the `#tailor` IRC channel on the freenode.net network. Do not hesitate to contact me either by email or chatting there.

[8] | I wish to say a big Thank you to Zooko, for hosting the ML and for supporting Tailor in several ways, from suggestions to bug reporting and fixing.

# Authors

Lele Gaifax <lele@nautilus.homeip.net>

Since I'm not currently using all the supported systems (so little time, so many VCSs...) I'm not in position to test them out properly, but I'll do my best to keep them in sync, maybe with your support :-)

## Aegis support

Aegis support was contributed by Walter Franzini.

## ArX support

ArX support was contributed by Walter Landry.

## Bazaar support

Bazaar support was contributed by Johan Rydberg. Nowadays it's being maintained by Lalo Martins.

## Git support

Git support was contributed by Todd Mokros.

## Monotone support

Monotone support was kindly contributed by Markus Schiltknecht and further developed by rghetta, that was able to linearize the multi-headed monotone history into something tailor groks. Kudos! More recently, Henry Nestler contributed various enhancements, like using `automate` instead `list` and tag support.

## Perforce support

Perforce support was kindly contributed by Dustin Sallings.

## Tla support

Tla support was contributed by Robin Farine.

# License

Tailor is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program in the file `COPYING`. If not, see this web page.

# About this document

This document and most of the internal documentation use the reStructuredText format so that it can be easily converted into other formats, such as HTML. For more information about this, please see:

> http://docutils.sourceforge.net/rst.html