A tool to exchange changesets between different version control systems
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setup.py Cosmetic Jun 1, 2008


Tailor 1.0


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 |
+--------------+         +------------+            +------------+

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.


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.


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!


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


$ sh run-all-test.sh


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).


  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


    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.

    1. 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.


    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.

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

      $ tailor -v --configfile cmfcore.tailor
  1. 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.


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:

verbose = True
projects = tailor

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

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

repository = file:///tmp/testtai
module = /project1
subdir = svnside

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:

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

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

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

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

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:

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

module = calife--pam--3.0
repository = roberto@keltia.net--2003-depot
subdir = tla

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:

#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





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

module = net.venge.monotone.cvssync.attrs
subdir = mtnside-net.venge.monotone.cvssync.attrs

module = net.venge.monotone.de
subdir = mtnside-net.venge.monotone.de

module = net.venge.monotone.svn_import
subdir = mtnside-net.venge.monotone.svn_import

module = net.venge.monotone
subdir = mtnside-net.venge.monotone

# Targets
module = branches/net.venge.monotone.cvssync
subdir = svnside-net.venge.monotone.cvssync

module = branches/net.venge.monotone.cvssync.attrs
subdir = svnside-net.venge.monotone.cvssync.attrs

module = branches/net.venge.monotone.de
subdir = svnside-net.venge.monotone.de

module = branches/net.venge.monotone.svn_import
subdir = svnside-net.venge.monotone.svn_import

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


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.


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


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

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:

patch-name-format=[%(project)s @ %(revision)s]: %(firstlogline)s
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.


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.


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:

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

target = monotone:productA
source = svn:sourceA

target = monotone:productB
source = darcs:sourceB

target = monotone:productC
source = svn:sourceC

target = darcs:
source = svn:sourceC


module = every.thing.productA

module = every.thing.productB

module = every.thing.productC

module = /productA

repository = http://some.server.com/darcs/productB

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.


Sample config fragment:

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

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.

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': 'Á',
  '\xc9': 'É',
  '\xcd': 'Í',
  '\xd3': 'Ó',
  '\xd6': 'Ö',
  '\xd5': 'Ő',
  '\xda': 'Ú',
  '\xdc': 'Ü',
  '\xdb': 'Ű',
  '\xe1': 'á',
  '\xe9': 'é',
  '\xed': 'í',
  '\xf3': 'ó',
  '\xf6': 'ö',
  '\xf5': 'ő',
  '\xfa': 'ú',
  '\xfc': 'ü',
  '\xfb': 'ű',
  '\xf1': 'ñ',
  '\xdf': 'ß',
  '\xe5': 'å'
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.


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.

metadir : string

The location of the _darcs repository, relative to subdir. This is useful, e.g., to handle svn:externals, and more generally to merge multiple sources to a single darcs repository.

_darcs by default.

It allows you to specify the location of the _darcs repository, which makes it possible to have the following structure:

- target_repo
  | _darcs
  | source_repo_A
    | source_repo_C
    | source_repo_D
  | source_repo_B
    | source_repo_E

Every source_repo (from A to E) is registered in target_repo, merging them in a single darcs repository (but you still need five target repository in the config file, to specify each metadir).

Here is a sample config (from a real-world example) to give you and idea of how I use it (with a "disjunct working directories" scheme):

projects = cil,ocamlutil
root-directory = /tmp/test

source = svn:cil
start-revision = 10792
state-file = cil.tailor.state
target = darcs:cil
filter-badchars = True

source = svn:ocamlutil
start-revision = 10719
state-file = ocamlutil.tailor.state
target = darcs:ocamlutil
filter-badchars = True

module = /trunk/cil
repository = svn://hal.cs.berkeley.edu/home/svn/projects
subdir = cil-svn

subdir = cil-patched

module = /trunk/ocamlutil
repository = svn://hal.cs.berkeley.edu/home/svn/projects
subdir = cil-svn/ocamlutil

subdir = cil-patched/ocamlutil
metadir = ../_darcs


This setting must not be mistaken with the --repodir option from darcs. It should always match the following regexp: (../)*_darcs, since the metadir must be somewhere above subdir for darcs to handle it automatically.

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
  tailor -c from-intermediary.tailor

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.

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.
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

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" \

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:

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.


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

Example: module = branches/branch.name

[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:

patch-name-format = ''
source = darcs:source
target = darcs:target
start-revision = INITIAL

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

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

debug = False
verbose = True

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

python-path = /opt/src/bzr.dev
subdir = bzrside

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,
    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)

            if fname[-3:] == '.py':
        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.


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

keys = console

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

keys = root

level = INFO
handlers = console

keys = 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 ...
source = bzr:source
target = hg:target

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


level = DEBUG
handlers = 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.


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.


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

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