hgvs is intended to be a community project. Contributions of source code, test cases, and documentation are welcome!

This section describes development conventions and practices for the hgvs project. The intention is to help developers get up-to-speed quickly.


  • Development occurs in the default branch. (Release branches are named for the major-minor release, e.g., 0.4.x.)
  • Versioning follows Semantic Versioning.
  • The code version is determined solely by the hg tags. This version appears in the package name (e.g., hgvs-0.4.4-py2.py3-none-any.whl) and in the version returned by hgvs.__version__. Updating to a specific version (e.g., hg up -r 0.4.0) will get you exactly that version.
  • All significant development must have an associated issue in hgvs issues; create an issue if necessary. Other changes may have have an issue. Please develop using a bookmark or branch named for the issue, such as 44-normalization.
  • Pull requests should be narrowly focused around a bug or feature. Discrete commits with good log messages facilitate review. Consider collapsing/squashing commits with hgvs rebase --collapse ... to make the PR concise. Submit PRs against the default branch head (or close to it).
  • Abide by current code style. Use make reformat to reformat all code with yapf prior to submitting a PR.
  • Email the hgvs-discuss mailing list if you have questions.
  • Test your code with make test before you submit a PR.
  • Currently, only Python 2.7 is supported. Support for Python 3.5 is slated for the next release (#190).

A Quick Contribution Example

  • Clone the project locally with

    $ hg clone<your_username>/hgvs
  • Create a virtualenv (recommended)

    $ mkvirtualenv hgvs

    There are other ways to make python virtual environment. How you do this isn’t important, but using a virtual environment is good practice.

  • Prepare your environment

    $ make develop

    The Makefile in hgvs wraps functionality in, and also provides many useful rules. See make for more information.

  • Make a branch (for significant changes)

    If you expect to change multiple files, please work in a branch. Please name the branch like 141-formatter-class.

  • Code, code, code!

    You probably want to test code with:

    $ make test

    See Local UTA and make for tips on accellerating testing.

  • Reformat code

    This command will reformat the entire package in-place.:

    $ make reformat
    $ hg commit -m 'fixes #141: implements Formatter class'

    Be sure to commit changes afterward!

  • Commit and push:

    $ make test
    $ hg push

Using a local/alternative UTA instance

  • Install UTA from a PostgreSQL as described at in the UTA README.
  • Specify an alternate UTA instance.

The easiest way to use a UTA instance other than the default is by setting UTA_DB_URL. The format is postgresql://<user>:<pass>@<host>/<db>/<schema>. For example:


explicitly selects the public database, and


selects a local instance. Developers can test connectivity like this:

$ UTA_DB_URL=postgresql://localhost/uta/uta_20140210 make test-quick

See hgvs/dataproviders/ for current UTA database URLs.

Get Cozy with make

The hgvs package includes a GNU Makefile that aids nearly all developer tasks. It subsumes much of the functionality in While using the Makefile isn’t required to develop, it is the official way to invoke tools, tests, and other development features. Type make for hgvs-specific help.

Some of the key targets are:

develop:Prepare the directory for local development.
install:Install hgvs (as with python install).
test:Run the default test suite (~4 minutes).
test-quick:Run the quick test suite (~35s) of most functionality.
clean, cleaner, cleanest:
 Remove extraneous files, leaving a directory in various states of tidiness.
docs:Make the sphinx docs in docs/build/html/.

Code Style

The package coding style is based roughly on PEP8, with the following changes:

column_limit = 120
spaces_before_comment = 4
split_before_named_assigns = True

These code conventions are uniformly enforce by yapf. The entire code base is periodically automatically reformatted for consistency.


The following code variable conventions are used for most of the hgvs code base. They should be considered aspirations rather than reality or policy. Understanding these conventions will help uses and developers understand the code.


A note on variable suffixes If a particular variant type is expected, a suffix is often added to variable names. e.g., var_c in a function argument list signifies that a SequenceVariant object with type=’c’ is expected.

hgvs*:a string representing an HGVS variant name.
var*:a hgvs.variant.SequenceVariant object

Release Process

hgvs uses a home-grown tool, clogger, to generate change logs. This section documents the process. (Clogger will be released at some point, but it is currently really only executable by Reece.)

clogger’s primary goal is to propose a preliminary changelog based on commit messages between specified release tags. That .clog file is a simple format like this:

clog format: 1; -*-outline-*-
* 0.4.1 (2015-09-14)
Changes since 0.4.0 (2015-09-09).
** Bug Fixes
*** fixes #274, #275: initialize normalizer with same alt_aln_method as AssemblyMapper [43e174d6f8af]
*** fixes #276: raise error when user attempts to map to/from c. with non-coding transcript [3f7b659f4f02]

.clog files should be edited for readability during the release process and committed to the repo (in hgvs/docs/changelog/).

A Makefile in the same directory generates an .rst file from the .clog. This file must also be committed to the repo. This file becomes the release changelog.

Finally, releases are bundled by major.minor versions in a file like 0.4.rst (no patch level). That file must be edited to include the new release and committed to the repo.

Specific Example – 0.4.3 release

The 0.4.x branch has two recent changes for the 0.4.3 release. Here’s how the release was prepared:

hg up 0.4.x
hg tag 0.4.3cl

cd docs/changelog
make 0.4.3cl.clog
mv 0.4.3cl.clog 0.4.3.clog
#edit 0.4.3.clog for readability
make 0.4.3.rst
#edit 0.4.rst to add 0.4.3 to index

cd ../.. (hgvs top-level), then hg status should now look like:

M docs/changelog/0.4.rst
A docs/changelog/0.4.3.clog
A docs/changelog/0.4.3.rst

Check your work. Type make docs, then view build/sphinx/html/changelog/0.4.3.html.

Now we’re ready to finish up:

hg tag --remove 0.4.3cl
hg com -m 'added docs for 0.4.3 release'
hg tag 0.4.3
hg push
make upload # (builds distribution and uploads to pypi)