Allow generating --dev projects outside Phoenix source

[jeffkreeftmeijer]

Right now, generating a Phoenix project with the --dev flag throws an error if the generated project is not inside the installer directory in the Phoenix source;

  $ mix phoenix.new /Users/jeff/opensource/phoenix_edge --dev
  Compiled lib/phoenix_new.ex
  Generated phoenix_new app
  ** (Mix) --dev project must be inside Phoenix directory

After poking around for a bit, I wasn’t able to find a reason for this, and I found that projects generated with the --dev flag would work properly anywhere if I just changed the path to Phoenix to an absolute one in the project’s mix.exs file.

So, I removed the code that checks if the project path is inside phoenix/installer and simply returned the absolute path to the Phoenix source when the --dev flag is used, which results in this line in the generated mix.exs file;

  [{:phoenix, path: "/Users/jeff/opensource/phoenix", override: true},

That eliminates the "--dev project must be inside Phoenix directory”-error and cleans up installer/lib/phoenix_new.ex quite a bit. What do you think? Did I miss anything?

[josevalim]

Hey @jeffkreeftmeijer, the issue I ran with this was related to brunch. I believe brunch can't find your assets if you use absolute paths. Try scaffolding a resource in an app with --dev and see if the delete button works and see if Phoenix.Socket is there.

[josevalim]

And thanks for the PR!

[jeffkreeftmeijer]

Hey @josevalim, thanks for the pointers and your quick reply. Brunch worked fine for me, so I did some testing and found that the assets were generated properly on Brunch 1.8.5, but not on earlier versions.

So, depending on "^1.8.5" instead of "^1.8.1" would solve this issue. Do you want me to change that in package.json?

[josevalim]

Yes, please. I am also worried about this:

https://github.com/jeffkreeftmeijer/phoenix/blob/dev-projects-outside-phoenix-directory/installer/lib/phoenix_new.ex#L466

This means the brunch file has a path to "../Users/jeff/..". It would be really weird if that is working. If you can check that too, it would be great, if not, I can check it before merging. Thank you!

[jeffkreeftmeijer]

After some more testing, I found Phoenix.Socket was indeed missing, caused by using the absolute path to phoenix.js in the Phoenix source in web/static/js/app.js;

  import {Socket} from "/Users/jeff/opensource/phoenix/web/static/js/phoenix"

It works with a relative path, so I think our best bet is to reinstate phoenix_static_path and have that return a relative path from the project directory to the phoenix source directory. What do you think?

Also, I tried finding something like Ruby's Pathname#relative_path_from in Elixir, but couldn't find it. Does a function like that exist, before I reinvent the wheel?

[josevalim]

We have Path.relative_from but it is not guaranteed to give a relative path if they are two distinct path structures. In other words, if you have it /foo/bar and /bat/bat, it won't make it ../../foo/bar because they are disjoint.

At this point, I am wondering if it is worth to continue chasing this. The --dev flag is a development only thing, so we can try things out, and requiring the same filepath seems like an OK restriction.

[jeffkreeftmeijer]

Yes, I found Path.relative_from, but wondered if I was missing anything.

This seemed like a simple thing to do as my first patch, but I agree this has gotten out of hand a little, so I'll close this. Thanks a lot for your help!

[wsmoak]

Thanks for exploring whether this could be changed! #1227 proposes adding more info to the README so the next person along doesn't have to re-discover it. :)