title: Vscode - variable expansion in .env file
body: <p>Running python tests in VSCode.  I have a <code>.env</code> file that <strong>is</strong> loading (I can add new vars, and see the change reflected in a <code>print(...</code> of <code>os.environ</code>.</p>
  <p>However, variable expansion within that file is doing something odd.  It seems to expand <code>${workspaceFolder}</code> in some cases (specifically, <code>PYTHONPATH=</code>) but <strong>not</strong> others. ??</p>
  <p>Here's my <code>.env</code> file.  Again, it <strong>is</strong> loading, as I can see changes if i add vars, or change the contents of the (fully working) <code>PYTHONPATH</code> var:</p>
  <pre><code>FOOBAR1=${workspaceFolder}/foobar1.txt
  PYTHONPATH=${workspaceFolder}/backend/src:/tmp/foo-2:${env:PYTHONPATH}
  </code></pre>
  <p>however <code>print(</code>'ing all the <code>os.environ</code>'s shows:</p>
  <pre><code>...
          ?
          v
  FOOBAR1=/foobar1.txt
  PYTHONPATH=/home/-omitted-/backend/src:/tmp/foo-2:
  ...
  </code></pre>
  <p><code>${workspaceFolder}</code> is expanded for one var, but not the other??  I've tried re-ordering.  Don't see anything here or on google.</p>
  <p>Help !?  Thank you!</p>