build instructions do not work as stated in "getting started"

[doebi]

Hi. I am trying to get going with thunderbird development, but although following the getting started the build fails.

These are the instructions I am following:
https://developer.thunderbird.net/thunderbird-development/building-thunderbird

getting mercurial, source checkout and setting up prerequisites works fine.
Without a custom mozconfig I am also able to successfully build firefox, but as soon as I add mozconfig, it breaks.

The error I get: TypeError: 'NoneType' object is not subscriptable
More log: https://pastebin.com/ZPUv5PW0

This is the content of my mozconfig as recommended in the getting started:

ac_add_options --enable-project=comm/mail
ac_add_options --enable-debug

When reading further links on your documentation I discovered several broken links:
https://developer.mozilla.org/en-US/Configuring_Build_Options
https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/mach

Are these docs out of date. If so, where can I find up to date ones?
How do I get started with thunderbird development?

Thanks.

[jobisoft]

The definition of

ac_add_options --enable-project=comm/mail

has been changed recently. Can you try if enable-application instead of enable-project works?

[doebi]

Looking promising. Build is running. Thanks.

This little detail cost me a full day of work. :/

[jobisoft]

What release are you building? comm-central or comm-beta?

[doebi]

I have both checked out, since this was part of the troubleshooting process. ATM: comm-beta

[jobisoft]

enable-application is the old flag and enable-project is the new one. We will check why the new one is not working as expected.

Thanks for notifying us. I am very sorry for your hassle.

[jfx2006]

My fault, I updated the docs prematurely.

--enable-project works as documented now on comm-central. (Since bug 1803012 this week.)

It will work on comm-beta when 109 goes to beta next week.

For comm-esr102, --enable-application is still needed, I will take care of that in an upcoming release.

[jfx2006]

Side note.. the docs should probably state in big bold type that they are for building comm-central, and YMMV when building beta or stable. These are development docs. Development happens on comm-central.