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This page pertains to UD version 2.

Release checklist

This checklist is meant to provide guidance for teams contributing treebank data for a new release of Universal Dependencies. It was created for release v1.2 and applies, unless otherwise noted, to any upcoming release.


Executive summary

Repository and files

Every language has its own GitHub repository called UD_Language, where Language is the name of the language. For example, the repository for Finnish is called UD_Finnish. Make sure to create the repository for your language if it does not already exist. Some languages have more than one treebank and the additional treebanks have their own repositories with a -Treebank identifier after the language name. For example, UD_Finnish-FTB is the repository for the FinnTreeBank, while the plain UD_Finnish holds the Turku Dependency Treebank.

Every language repository should contain the following five files (where xx is the ISO code for the given language; if this is not the first treebank for the language, use xx_y instead, where y is the lowercased treebank identifier):

  1. xx-ud-train.conllu
  2. xx-ud-dev.conllu
  3. xx-ud-test.conllu temporary rule for UD 2.0: do not publish the test set! Validate it offline and then send it by e-mail to ud.conll.shared.task.2017@gmail.com.
  4. README.txt or README.md
  5. LICENSE.txt

The first three files contain the treebank data split into a training, development and test set. These should be in CONLL-U format and conform to the universal guidelines. They need to be validated as described below.

If the treebank consists of more than 20,000 words, make the test set and dev set at least 10,000 words each, even if it leaves you with training data smaller than development data (that is necessary for the CoNLL 2017 shared task). There is no upper limit on the size of dev/test. If you cannot reach 10,000 words of test data, use a more typical split, e.g. 80-10-10% (but the treebank will not be included in the shared task).

The training-development-test data split should be stable across releases. It should not happen that a sentence that was once part of training data ever appears in the test data, and vice versa (except for sentences that are naturally occurring duplicates in independent texts). We want to prevent accidental misguided results of experiments where people take a parser trained on UD 1.1 and apply it to test data from UD 1.2. We decided to make an exception to this rule for UD 2.0 where it is needed to achieve 10K test or dev, on the ground that v2 annotation is not backward-compatible anyway.

The README.txt file contains basic documentation of the treebank and machine-readable metadata for the UD main page (see below) and the LICENSE.txt specifies under what license the treebank is made available.

Repositories of released treebanks also contain a stats.xml file, which is generated as part of the release-building process, using the script conllu-stats.pl available from the tools repository. Data providers do not have to care about this file.

The README file

The README file should minimally contain the following information:

  1. A description of the treebank and its origin (creation method, data sources, etc.)
  2. A description of how the data was split into training, development and test sets
  3. Basic statistics about number of sentences, tokens, etc.
  4. Acknowledgments and references that should be cited when using the treebank
  5. A machine-readable section with language metadata. This is described below.

Note that the basic statistics can be produced using the script conllu-stats.pyavailable from the tools repository and run as follows:

$ python conllu-stats.py --stats ../UD_Finnish/*.conllu

For previously released corpora, the README file should also include a “changelog” section summarizing changes between versions e.g. as follows


2015-05-15 v1.1
    * Added lemmas
    * Corrected tokenization in sentences 123 and 456

Language metadata

The readme file contains metadata used to generate the overview table on the UD main page: data source, license, genres, and documentation status. The format of this metadata is described here

The table on the front page is automatically generated from special lines in the README.txt or README.md file for every language. This means that in order to add a new language, also its repository must be created, minimally with the readme file. Here is an example of the language metadata block from the Finnish README file

=== Machine-readable metadata (DO NOT REMOVE!) ================================
Documentation status: complete
Data source: semi-automatic
Data available since: UD v1.0
License: CC BY-SA 4.0
Genre: blog wiki legal news fiction
Contributors: Ginter, Filip; Kanerva, Jenna; Laippala, Veronika; Missilä, Anna; Pyysalo, Sampo
Contact: turku@treebank.org

This block can be anywhere in the readme file. The properties are as follows:

Repository branches

While the official UD release is always through Lindat, many users of UD source their data from the GitHub language repositories. Therefore, the master branch of every language should contain the last, officially released version of the data for the given language. The development in between releases should happen on the dev branch of the repository. Although it is currently not locked, treebank maintainers should never touch the master branch, they should always push to dev. At release time, the release task force will take care of merging the contents of the dev branch into master. Please do not submit pull requests from the dev branch (or from anywhere else) to the master branch. This is not needed for the release merge to take place, and if someone overlooks the destination branch and accepts the pull request, it will again result in a commit to the master branch at wrong time.

(To make things a bit more confusing, this policy of data repositories does not apply to some other repositories that we use. In the docs repository you must work with the pages-source branch. That is done automatically if you edit the documentation in your browser via the edit page link. You will also need to access the tools repository and upload the deprel and feat_val files specific for your treebank. In this case, please use the master branch.)

If you have no previous experience with Git, here is a quick tutorial on how to deal with the branches. Please refer to on-line documentation of Git and Github for more details. The tutorial assumes that you are communicating with Github from a Linux shell. The interface may be different if your OS is Windows. If you are working only with the Github web interface, you are not dependent on your operating system but you must remember to switch the Branch: master drop-down menu (left-hand side of the page) to Branch: dev; it always starts in master by default. In contrast, when you want to clone the repository to your local system, you need the address that is hidden under Clone or download in the right-hand side of the page, and that address is common for all branches. Our example is the Italian repository. Here is how you clone the repo to your system (git clone is the command, the remainder is the address copied from the Github web):

git clone git@github.com:UniversalDependencies/UD_Italian.git
Cloning into 'UD_Italian'...
remote: Counting objects: 215, done.
remote: Total 215 (delta 0), reused 0 (delta 0), pack-reused 215
Receiving objects: 100% (215/215), 6.98 MiB | 4.55 MiB/s, done.
Resolving deltas: 100% (134/134), done.
Checking connectivity... done.

Then enter the cloned folder and switch to (“checkout”) the dev branch. Your copy of the repository knows that such a branch exists on the server but it only creates your local copy of that branch once you ask for it. You may subsequently want to call git pull to make sure that you have the latest contents of the dev branch from the server:

cd UD_Italian
git checkout dev
Branch dev set up to track remote branch dev from origin.
Switched to a new branch 'dev'
git branch
* dev
git pull
Already up-to-date.

Once you do this, you are all set. Your copy will stay switched to the dev branch unless you call git checkout master (or other git checkout) again. You will probably mostly need just git status, git diff, git add, git commit, git push and git pull commands. All pushes and pulls will be done against the remote dev branch.


Data format and repository

Up-to-date automatic validation runs of the repositories are available here. These are based on the dev branch of the data and use the validate.py script described below.

The final data validation is an important step and each file released in the project is expected to validate as conforming to the basic requirements on the data and format. For this purpose, there is a validation script in the tools repository.

$ git clone git@github.com:UniversalDependencies/tools.git
$ cd tools
$ python validate.py -h

In general, you validate the data like so:

python validate.py --lang=xx [file.conllu]

for example for Finnish:

$ python validate.py --lang=fi ../UD_Finnish/fi-ud-dev.conllu 
*** PASSED ***

Among other items, the script also validates the language-specific set of tags and relations and therefore it needs to know about these. The language-specific lists are stored in data/deprel.xx (language-specific relations) and data/feat_val.xx (language-specific features). In addition data/*.ud stores the UD taglists. Before you can validate data for a given language, you need to produce and commit the necessary tag lists. You can make the initial lists like so:

$ python conllu-stats.py --deprels=langspec path_to_your_data/*.conllu > data/deprel.xx
$ python conllu-stats.py --catvals=langspec path_to_your_data/*.conllu > data/feat_val.xx

This will gather the language-specific lists in descending order by their frequency. It is important to check the resulting files for correctness, because otherwise the validation would of course be a no-op. Once you have checked the lists manually, you can add them to the repository:

$ git add data/deprel.xx data/feat_val.xx
$ git commit -m "Adding language-specific data for xx."
$ git push

Since the v2.0 release, whitespace is allowed in the FORM and LEMMA fields under conditions specified in here. This is supported in the validator through the UD-wide file data/tokens_w_space.ud and its language-specific variants data/tokens_w_space.xx. In these files, each line is a Python regular expression defining the permissible forms and lemmas that can contain a whitespace.


For the v1.3 release, we have created an additional number of tests which try to uncover possible logical inconsistencies in the treebank data. Automatic validation runs for this syntax validation are available here. Unlike the data format and repository validation, this validation machinery is not streamlined enough to be distributed for offline use, therefore it is important to regularly push your data to the dev branch of the repository.

The tests are specified in the file gen_index/stests.yaml and rely on the query language of the SETS search interface.

Language-specific guidelines

Every treebank should be accompanied by a set of language-specific guidelines at http://universaldependencies.org/. These guidelines should minimally specify the following:

  1. Tokenization: How was word segmentation performed? Does the treebank include multiword tokens?
  2. POS tags: What universal POS tags (if any) are not used?
  3. Features: What universal features are not used? What language-specific features/values have been added?
  4. Relations: What universal relations are not used? What language-specific subtypes have been added?

There are more detailed guidelines for language-specific documentation. Also see the general guidelines about how to contribute (which covers the conventions used in writing UD documentation, such as how to format examples).

Building the release

Documentation of the steps to be taken by the release task force is on a separate page.