=========================
 External Library README
=========================

This directory contains two kinds of things: external dependencies
specified in package.json (which gets installed into the node_modules
directory), and full copies of third-party code, which we call
embedded code copies.


External dependencies specified in package.json
===============================================

package.json is a file that specifies external code dependencies. We
download those using the "npm" tool. As a developer of MediaGoblin,
install npm however is convenient for you (for example, apt-get
install npm).

If you are "merely installing" MediaGoblin (and aren't attempting to
change its code), you should know that the MediaGoblin team's main
release download, also known as the MediaGoblin mulltipack tarball,
contains a copy of all the code specified via package.json.

As a general rule, always specify dependencies in package.json using
"==" to pin to a specific release that you have tested MediaGoblin
with. The MediaGoblin team always welcomes patches that merely change
the version of a dependency so long as you have tested that the app
works. Doing this is a valuable and significant contribution to the
project.

Other notes about the contents of package.json:

* Inconsolata is available in the npm repositories, but it does not
  include the OTF font format, and at the time of writing it appears
  that PIL needs OTF/TTF and cannot accept a WOFF font file. For this
  reason, we have avoided using the Inconsolata package from npm.

* Lato is available in NPM as connect-fonts-lato, but the font file
  has a different hash than the file currently in extlib, so we are
  sticking with our extlib version until someone has time to test
  the NPM version. (That could be you!)


Embedded code copies
====================

DO NOT "FIX" CODE IN THIS DIRECTORY.

ONLY UPSTREAM VERSIONS OF SOFTWARE GO IN THIS DIRECTORY.

This directory is provided as a courtesy to our users who might be
unable or unwilling to find and install libraries we depend on.

If we "fix" software in this directory, we hamstring users who do the
right thing and keep a single version of upstream libraries in a
system-wide library.  We introduce subtle and maddening bugs where
our code is "accidentally" using the "wrong" library version.  We may
unwittingly interfere with other software that depends on the
canonical release versions of those same libraries!

Forking upstream software for trivial reasons makes us bad citizens in
the Free Software community and adds unnecessary heartache for our
users.  Don't make us "that" project.


FAQ
===

:Q: What should we do when we find a bug in upstream software?

:A: First and foremost, REPORT THE BUG, and if possible send in a patch.

    Watch for a release of the upstream software and integrate with it
    when it's released.

    In the meantime, work around the bug, if at all possible.  Usually,
    it's quite possible, if slightly harder or less efficient.

:Q: What if the bug can't be worked around?

:A: If the upstream developers have accepted a bug patch, it's
    undesirable but acceptable to apply that patch to the library in
    the ``extlib/`` dir.  Ideally, use a release version for upstream or a
    version control system snapshot.

    Note that this is a last resort.

:Q: What if upstream is unresponsive or won't accept a patch?

:A: Try again.

:Q: I tried again, and upstream is still unresponsive and nobody's
    checked on my patch.  Now what?

:A: If the upstream project is moribund and there's a way to adopt it,
    propose having the MediaGoblin dev team adopt the project.  Or, adopt
    it yourself.

:Q: What if there's no upstream authority and it can't be adopted?

:A: Then we fork it.  Make a new name and a new version. Include it in
    ``lib/`` instead of ``extlib/``, and use the GMG_* prefix to change
    the namespace to avoid collisions (or something like that).

    This is a last resort; consult with the rest of the dev group
    before taking this radical step.

:Q: What about submodules?

:A: pdf.js is supplied as a submodule, and other software may use that too,
    to add a new submodule:
     git submodule add <git-repo-of-fun-project> extlib/fun-project

    Use it just like a snapshotted extlib directory. When a new clone of mediagoblin
    is made you need to run

     git submodule init
     git submodule update

    As noted in HackingHowto

Thanks
======

This policy originally copied from Status.net.  Many many thanks to them
for working out such a nice system for doing things.
