How To Slide Your Release Past The Incubator

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Who am I?

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I am not a Lawyer

  • I’m not a lawyer, and nothing on these sides is legal advice

  • Occasionally I get things wrong

  • My understanding has changed over time

  • Sometimes it’s complex, and there’s more than one “right” answer

  • I’m a volunteer and not paid to do this. Not even by my day job

  • This talk contains my views and may not represent the incubator as a whole

What is the Apache Incubator?

  • Main entry point for new projects

  • Where communities come to learn the Apache Way

  • Links existing projects with a community around them

Why we Have an Incubating Process?

  • Ensure donations comply with the Apache 2.0 license

  • Podling follows the ASF structure of contributors, committers and PMC members

  • Podling grants more responsibility via meritocracy

  • Ensure that decision making is done in the open

  • People act as individuals, not the company they work for

  • Podling learns to follow the Apache Way

The Apache Way

  • Charity - For the public good. Software costs nothing

  • Pragmatic - Business friendly

  • Community - Collaboration, consensus and diversity

  • Merit - The more you do you more responsibility you have. Not just code contributions

  • Open - Everything in the public view. Discussions occur on mailing lists. Everyone can participate

  • Consensus - Work together to find ways forward

Apache License

  • Permissive license - you can do what you want

  • Business friendly - can be used for commercial projects

  • Requires source headers, a LICENSE and (optionally) a NOTICE file

  • If your are not an ASF project:

    • You don’t need to publish the source

    • You don’t have to give back to the project

    • You don’t need to ask for permission to use

State of Play

  • 48 projects in the incubator

  • 306 IPMC members (but not all are active)

  • Projects usually stay around 2 years in the incubator

  • A dozen or so successful releases a month

  • About 80% of releases pass the incubator

Source Releases

  • Must be cryptographically signed

  • Must have an incubating disclaimer (there’s two now)

  • Have LICENSE and NOTICE file that follow Apache policy

  • Follow licensing terms of any 3rd party bundled software

  • 3rd party files are compatible with the Apache license

  • Source files have ASF headers

  • Contain source code and no compiled code

Work in Progress Disclaimer

  • Less strict and your release may not comply with ASF policy

  • Must still be legal

  • You can list known issues

  • Issues noted must be fixed before graduation

Incubator Vote Process

  • Podling creates a release candidate

  • Vote on dev mailing list until 3 +1 votes and more +1 than -1

  • If vote fails need to make a new release candidate

  • Vote on incubator general mailing list

  • Need 3 +1 and more +1 than -1 by IPMC members

  • If vote fails need to make a new release candidate

  • Can release once vote passes and 72 hours pass

Why Your Release May Get a -1

  • Unexpected binary in the source release

  • Includes Category X licensed software (usually GPL)

  • Included Category B license software

  • LICENSE or NOTICE issue

  • Copyright issue

  • Missing license header or header issue

  • Contains encryption software

Representative Voting

  • About 80% of releases pass

  • Slight improvement on past years

  • Work in progress disclaimer will change this

-1 is Not a Veto

  • Release votes need 3 +1 votes and more +1 than -1 votes to pass

  • Only IPMC votes are binding but good to take notice of other votes

  • People can change their minds and vote again

  • People can put up conditional votes

  • A -1 vote needs a good reason

It Doesn’t Have to be Perfect

  • Incubating projects are not expected to get it right the first time

  • May not be familiar with policy at the start

  • Policy an guidelines doesn’t cover all situations

  • Different projects may do things in different ways

  • A release containing no surprises is a good thing

Make it Easy to Review

  • Don’t make people have to think hard about it

  • Provide well-named artefacts

  • Don’t try to be clever with licensing or headers or rat exclusions

  • Include compile instructions in the release

  • Make it easy to compile

There’s Not One Right Answer

  • Documentation can sometimes be confusing and sometimes out of date

  • Some cultural knowledge isn’t well documented

  • Large IPMC and some differing opinions on what is “correct”

  • Often multiple ways to solve the same issue

  • If in doubt err on the side of caution, often changes needed are minimal


Again guidelines not rules. You can do things in a different way.

Top Level Projects As Examples

  • Policy changes over time / may be out of date

  • A project may have its own reasons for doing something in a certain way

  • Take care when looking at TLPs for examples

  • Probably better to look at TLPs that have recently graduated

Cryptographic Signing

  • Release must be cryptographically signed

  • Keys need to be RSA with at least 4096 bits

  • Good idea to use an email address

  • Use sha256 or sha512 for hash


  • Two different disclaimers

  • Put in a file called DISCLAIMER or DISCLAIMER_WIP

  • Could also be in README


  • Good idea to tag releases

  • That way that can be easily compared to what is released

  • Can also be easily checked out and built if needed in the future

  • Note that git tags can be changed so provide hash in vote email


  • This is where a lot of the issues occur

  • Observed some reluctance to understand

  • Language barrier to even those who speak English

  • Can be complex

  • ASF Policy does change over time

Developers vs Licensing

  • We’re not the only people who have difficulty or frustration with licensing

  • Apache projects tend to be on average a lot better!

  • External projects often:

    • Have unclear licenses

    • Include code under a different, sometimes incompatible, licenses

    • If Apache 2.0 licensed are missing a NOTICE file

    • Try to use funny licenses

33 Copies of BSD

WTF Intel Lawyers

Only Dead People


Documentation Issues vs Errors

  • It’s better to have a documentation issue than a licensing error

  • Minor issues are OK to be fixed in the next release

  • If you’re unsure a license should be listed list it

Universal Donor

  • Give anyone confidence they can use our software without any legal issues

  • All software within an artefact is compatible with the Apache 2.0 licence

  • Means it can be used for commercial and non-commercial purposes

Guiding Principle

  • The LICENSE and NOTICE files accurately represent the contents of the distribution they belong to

  • Don’t mention stuff that’s not include in the release

  • There’s need to mention external dependencies in LICENSE and NOTICE

  • Applies to both source and binary artefacts

May Contain Nuts

  • When bundling software check to see what it contains

  • In particular look for Category B and Category X software

  • Look at photos or other resources like fonts that you may not have permissions to distribute or may be under another license

  • Check links in code

  • Manual inspection is not always required but often a good idea


  • Great tool for finding binaries and licenses in your source release

  • Not perfect but very handy

  • Will not find double headers

  • Will not check for multiple licenses in the same file

  • Only knows about a few licenses

  • Often exclusions can be too wide and miss something

Rat Output


Finding Licenses

  • One way is to use find and grep
    find . -type f -exec grep -i "$1" {} \;

  • Search for common license names “GPL”, “BSD”, “MIT”

  • Search for “copyright” and pipe to sort -u

  • Compare between releases

Pesky JS files

  • JS files, especially minified ones, are often missing license headers or license details

  • Some license require full text to be contained somewhere

  • Lots are under non-Apache licenses including GPL

  • Other included other bundled software e.g. jQuery and Bootstrap

  • Licenses change between versions

  • Take care!

Other People’s Cat Photos

  • Copy all the images!
    find . -name "*.jpg" -exec cp {} images \;

  • View all images using your OS or favourite image browsing tool

  • If you find something that may be suspect:

    • Look at image metadata

    • Find it with a Google reverse image search

Troublesome Fonts

  • Licensing around fonts can be complex

  • Look at font meta-data

  • Make sure you have permission to distribute

  • As fonts are binary may not be evident to users how they are licensed. You may want to make that clear in the LICENSE file

License File

  • License file named LICENSE or LICENSE.txt in the root directory

  • Contains Apache license and list of licenses of bundled software in a distribution

  • Short form pointer to license preferred

  • May have different contents for source and binary

License File


Notice File

  • Contains ASF copyright and developed at the ASF notice

  • Keep year up to date

  • Only add what is needed

    • Relocated copyright notices

    • Content from bundled Apache software notice files

    • All other required notices

  • In general licensing info shouldn’t be in the notice file

Notice file


Required Notices

  • Some confusion to what to what a required notice is

  • Advertising clauses (but are probably category X)

  • Link to the source / how to get original

  • State changes made

  • Are not copyright notices

Category A

  • Can bundle software and can depend on

  • Doesn’t add any restrictions above and beyond what the Apache License 2.0 does

  • Common licenses include:
    Apache License 2.0, Apache License 1.1, 2 or 3 clause BSD (without advertising clause), MIT/X11, W3C, Unicode, CC copyright only

Category B

  • Probably can’t include in a source release

  • Contains some restriction of use

  • May be able to use the binary form to limit the chance of corruption

  • Common license include:
    Common Development and Distribution License (CDDL), Eclipse Public License (EPL), Mozilla Public License (MPL), most Creative Common licenses

Category X

  • Can’t depend on

  • Can’t bundle software

  • A few exceptions for build tools and optional dependencies

  • Common Category X include:
    GPL, LGPL, CC non commercial, JSON, BSD 4 clause, Apache 1.0?

No Unexpected Binary Files

  • No compiled source in a source release

  • No exes, dlls, jars or class files please

  • No minified JS without source


  • All Apache licensed source files should have an ASF header

  • Don’t include a copyright line

  • Use correct header

Can Compile From Code

  • Helps to have clear instructions on how to in the release

  • If it doesn’t work on a platform, please note that

  • If you need to install a 3rd party component to get it to compile, please note that

  • Make it easy to compile

Apache Wombat

Wombat Walk Through

  • Get boilerplate LICENSE and NOTICE files via curl

  • Get NOTICE file to correct copyright and year

  • Add Bootstrap’s MIT license to LICENSE

  • index.html contains HTML shiv which is dual licensed MIT/GPL

  • Add HTML shiv MIT to LICENSE

  • index.html depends on Respond.js and jQuery but not bundled

  • Bootstrap bundles normalize.js add MIT to LICENSE

  • Glyphicon fonts are MIT license add to LICENSE

Nice to Haves

  • Up to date README

  • Up to date CHANGES

  • KEYS file published

  • list of DEPENDENCIES

Common Mistakes

  • Unexpected binary files in the source release

  • Contents of LICENSE and NOTICE files

  • Source and binary have same LICENSE and NOTICE

  • Missing headers

  • Issues missed due to Rat exclusions

  • Issues missed due to automation

  • Missing DISCLAIMER

  • Release not in the correct place

Binary Distributions

  • Not considered an official release

  • Need to comply the same way with ASF policies as source distributions

  • LICENSE and NOTICE may be different as the contents of the release is often different from the source release

Where to Ask for Help

The Incubator is Broken

  • Every few years this comes up, I don’t think it is, but like most things, it’s not perfect

  • It adds a lot of value for a relatively small amount of work for those involved

  • Follow the general list and see what issues incubating projects do/don’t run into

  • We could do with more help. Get involved! You don’t have to be an ASF member

  • We need more people reviewing releases and helping improve documentation

We’re here to help

How can we improve? Please email the incubator mailing list at: We’re happy to talk about it. Perhaps a bit too much :-)


Ask now, see me after the session, or email me, Your Name at Your email.

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