title: Fetching Go package dependencies using tags
body: <p>How can I fetch all the dependencies of Go packages at once using version tags on specific imports ?</p>
  
  <p>Say I have my go tree with multiple packages in it :</p>
  
  <pre><code>src/
      foo/
          bar/               (go code in package bar)
              x.go
          quux/              (go code in package main)
              y.go
  </code></pre>
  
  <p>Now let the package `bar' depends on a third party library that use tag versions<br>
  (i.e. usually fetched with : <strong>go get -tags mylib_2.0 github.com/user/mylib</strong>)</p>
  
  <p>What I want to do is to specify a tag on the import line
  so that <strong>go get ./...</strong> on my tree gets the correct version scheme. Something like:</p>
  
  <pre><code>import "github.com/user/mylib" `tags=mylib_2.0`
  </code></pre>