fix(dataDirs): fix crash when python is not in path

[Jaykul]

Properly handle the case when guessSysPrefix can't find anything (i.e.: when python isn't installed)

[rgbkrk]

Welcome to the nteract party! 🎉

[rgbkrk]

Tests fail locally on my system, though I'm not sure if/what I should change.

$ npm t

> jupyter-paths@1.1.0 test /Users/kylek/code/src/github.com/nteract/jupyter-paths
> mocha

  dataDirs
    1) returns a promise that resolves to a list of directories that exist
    ✓ works even in the absence of python
    ✓ returns a promise that resolves to a list of directories that exist (104ms)
    2) returns immediately with a guess by default

  runtimeDir
    ✓ returns the directory where runtime data is stored

  configDirs
    3) returns a promise that resolves to a list of directories that exist
    ✓ returns a promise that resolves to a list of directories that exist
    4) returns immediately with a guess by default

  4 passing (129ms)
  4 failing

  1) dataDirs returns a promise that resolves to a list of directories that exist:

      AssertionError: expected [ Array(4) ] to deeply equal [ Array(4) ]
      + expected - actual

       [
         "/users/kylek/library/jupyter"
      -  "/usr/local/cellar/python/2.7.13/frameworks/python.framework/versions/2.7/share/jupyter"
      +  "/usr/local/cellar/python3/3.6.1/frameworks/python.framework/versions/3.6/share/jupyter"
         "/usr/local/share/jupyter"
         "/usr/share/jupyter"
       ]

      at Proxy.assertEqual (node_modules/chai/lib/chai/core/assertions.js:1012:19)
      at Proxy.methodWrapper (node_modules/chai/lib/chai/utils/addMethod.js:57:25)
      at jp.dataDirs.then (test/jupyter_paths_spec.js:28:37)
      at <anonymous>

  2) dataDirs returns immediately with a guess by default:

      AssertionError: expected [ Array(4) ] to deeply equal [ Array(4) ]
      + expected - actual

       [
         "/users/kylek/library/jupyter"
      -  "/usr/local/cellar/python/2.7.13/frameworks/python.framework/versions/2.7/share/jupyter"
      +  "/usr/local/cellar/python3/3.6.1/frameworks/python.framework/versions/3.6/share/jupyter"
         "/usr/local/share/jupyter"
         "/usr/share/jupyter"
       ]

      at Proxy.assertEqual (node_modules/chai/lib/chai/core/assertions.js:1012:19)
      at Proxy.methodWrapper (node_modules/chai/lib/chai/utils/addMethod.js:57:25)
      at Context.it (test/jupyter_paths_spec.js:67:26)

  3) configDirs returns a promise that resolves to a list of directories that exist:

      AssertionError: expected [ Array(4) ] to deeply equal [ Array(4) ]
      + expected - actual

       [
         "/users/kylek/.jupyter"
      -  "/usr/local/cellar/python/2.7.13/frameworks/python.framework/versions/2.7/etc/jupyter"
      +  "/usr/local/cellar/python3/3.6.1/frameworks/python.framework/versions/3.6/etc/jupyter"
         "/usr/local/etc/jupyter"
         "/etc/jupyter"
       ]

      at Proxy.assertEqual (node_modules/chai/lib/chai/core/assertions.js:1012:19)
      at Proxy.methodWrapper (node_modules/chai/lib/chai/utils/addMethod.js:57:25)
      at jp.configDirs.then (test/jupyter_paths_spec.js:86:37)
      at <anonymous>

  4) configDirs returns immediately with a guess by default:

      AssertionError: expected [ Array(4) ] to deeply equal [ Array(4) ]
      + expected - actual

       [
         "/users/kylek/.jupyter"
      -  "/usr/local/cellar/python/2.7.13/frameworks/python.framework/versions/2.7/etc/jupyter"
      +  "/usr/local/cellar/python3/3.6.1/frameworks/python.framework/versions/3.6/etc/jupyter"
         "/usr/local/etc/jupyter"
         "/etc/jupyter"
       ]

      at Proxy.assertEqual (node_modules/chai/lib/chai/core/assertions.js:1012:19)
      at Proxy.methodWrapper (node_modules/chai/lib/chai/utils/addMethod.js:57:25)
      at Context.it (test/jupyter_paths_spec.js:107:26)

[rgbkrk]

"My" jupyter is the python3 one whereas the expected is the Python2 jupyter. I think we'll ship with this as a major bump and assume that's just a me thing.

[rgbkrk]

$ npm version major && npm publish && git push && git push --tags
v2.0.0
+ jupyter-paths@2.0.0
Counting objects: 4, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 2.87 KiB | 0 bytes/s, done.
Total 4 (delta 2), reused 0 (delta 0)
remote: Resolving deltas: 100% (2/2), completed with 2 local objects.
To github.com:nteract/jupyter-paths.git
   d6e574c..e8d440b  master -> master
Counting objects: 1, done.
Writing objects: 100% (1/1), 155 bytes | 0 bytes/s, done.
Total 1 (delta 0), reused 0 (delta 0)
To github.com:nteract/jupyter-paths.git
 * [new tag]         v2.0.0 -> v2.0.0

[rgbkrk]

@lgeiger ^^

Shipped a new jupyter-paths as a major release.

[lgeiger]

@rgbkrk I'll test it on my system tomorrow.

[Jaykul]

@rgbkrk So the difference between guessSysPrefix and what jupyter --paths actually returns is obviously because the first python in your path is not the same version where you actually have jupyter installed (or at least, not the same python as the first place in your path where jupyter exists?).

In any case --in my lack of experience with this-- I would guess the fix would be to search for jupyter instead of python 😉