Made extension virtualenv aware by exporting VIRTUAL_ENV when bin/python detected from project root

Author: rob-a-bolton

lib/main.js

@@ -1,6 +1,7 @@
 const cp = require("child_process");
 const { shell } = require("electron");
 const { AutoLanguageClient } = require("atom-languageclient");
+const { Directory } = require("atom");
 
 // Ref: https://github.com/nteract/hydrogen/blob/master/lib/autocomplete-provider.js#L33
 // adapted from http://stackoverflow.com/q/5474008
@@ -30,8 +31,19 @@ class PythonLanguageClient extends AutoLanguageClient {
   async startServerProcess(projectPath) {
     await new Promise(resolve => atom.whenShellEnvironmentLoaded(resolve));
 
+    var venvPromise = new Directory(projectPath).getSubdirectory('bin')
+                                                .getFile('python')
+                                                .exists();
+
+    var pylsEnvironment = Object.assign({}, process.env);
+
+    if(await venvPromise) {
+      pylsEnvironment['VIRTUAL_ENV'] = projectPath;
+    }
+
     const childProcess = cp.spawn(atom.config.get("ide-python.pylsPath"), {
-      cwd: projectPath
+      cwd: projectPath,
+      env: pylsEnvironment
     });
     childProcess.on("error", err =>
       atom.notifications.addError(