I am using the guide to setup a development environment on ubuntu 16.04 from https://www.openproject.org/development/setting-up-development-environment/ but it is failing for me on branches dev, release/8.0 as well as stable/8 when trying to install jQuery-ui. It looks like a '/' is missing from github url right after https.
Installing jQuery-ui with npm install jquery-ui@git+https://github.com/jquery/jquery-ui.git#74f8a0ac952f6f45f773312292baef1c26d81300 succeeds, but doesn't help my npm install

Any clue what I should do to resolve this ?

Here is the full output:

cse@openproject-dev:~/openproject$ npm install

> openproject@0.1.0 postinstall /home/cse/openproject
> cd frontend && npm install

npm ERR! addLocal Could not install /home/cse/openproject/frontend/jquery-ui@git+https:/github.com/jquery/jquery-ui.git#74f8a0ac952f6f45f773312292baef1c26d81300
npm ERR! Linux 4.4.0-135-generic
npm ERR! argv "/home/cse/.nodenv/versions/6.11.0/bin/node" "/home/cse/.nodenv/versions/6.11.0/bin/npm" "install"
npm ERR! node v6.11.0
npm ERR! npm  v3.10.10
npm ERR! path /home/cse/openproject/frontend/jquery-ui@git+https:/github.com/jquery/jquery-ui.git#74f8a0ac952f6f45f773312292baef1c26d81300
npm ERR! code ENOENT
npm ERR! errno -2
npm ERR! syscall open

npm ERR! enoent ENOENT: no such file or directory, open '/home/cse/openproject/frontend/jquery-ui@git+https:/github.com/jquery/jquery-ui.git#74f8a0ac952f6f45f773312292baef1c26d81300'
npm ERR! enoent ENOENT: no such file or directory, open '/home/cse/openproject/frontend/jquery-ui@git+https:/github.com/jquery/jquery-ui.git#74f8a0ac952f6f45f773312292baef1c26d81300'
npm ERR! enoent This is most likely not a problem with npm itself
npm ERR! enoent and is related to npm not being able to find a file.
npm ERR! enoent

npm ERR! Please include the following file with any support request:
npm ERR!     /home/cse/openproject/frontend/npm-debug.log

npm ERR! Linux 4.4.0-135-generic
npm ERR! argv "/home/cse/.nodenv/versions/6.11.0/bin/node" "/home/cse/.nodenv/versions/6.11.0/bin/npm" "install"
npm ERR! node v6.11.0
npm ERR! npm  v3.10.10
npm ERR! code ELIFECYCLE
npm ERR! openproject@0.1.0 postinstall: `cd frontend && npm install`
npm ERR! Exit status 254
npm ERR!
npm ERR! Failed at the openproject@0.1.0 postinstall script 'cd frontend && npm install'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the openproject package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     cd frontend && npm install
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs openproject
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!     npm owner ls openproject
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /home/cse/openproject/npm-debug.log

The entry in package.json  looks correct to me. https://github.com/opf/openproject/blob/dev/frontend/package.json#L89

We did however change that recently so my suspicion is that git+https is not supported by npm 3 (I'm using node LTS 8.11 for development which ships with npm 6.2).

Can you try installing node LTS 8.11 and try again? I will update the development guide.

Best,

Oliver

You are spot on. I tried both node 8.11.4 (npm 5.6.0) and node 8.12.0 (npm 6.4.1), and they both seem to work flawlessly. Since 8.12.0 is the latest LTS at the time of writing, I suggest to use that version in the docs. 

thanks for your help!

Great to hear. I have updated the guide to use the newest LTS. https://github.com/opf/openproject/edit/dev/docs/development/development-environment-ubuntu.md

Since these versions are very volatile, the notice above still stands, we suggest to aways use the latest LTS for development since that's likeley what we'll use.

Understood. Thanks again!