From c59eaa05bb0345bde3ec08a49c1a31b4abec6fa2 Mon Sep 17 00:00:00 2001
From: Sebastian Serth <Sebastian.Serth@hpi.de>
Date: Fri, 14 Apr 2023 13:37:45 +0200
Subject: [PATCH] Handle bootstrapping of Poseidon when no environments

When starting Poseidon with an empty Nomad cluster, the list of existing environments is empty. In this case, however, our error handler threw an error, which was not correct.

Fixes CODEOCEAN-M7
---
 lib/runner/strategy/poseidon.rb | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/runner/strategy/poseidon.rb b/lib/runner/strategy/poseidon.rb
index 54ccf526..1f222a5b 100644
--- a/lib/runner/strategy/poseidon.rb
+++ b/lib/runner/strategy/poseidon.rb
@@ -27,12 +27,11 @@ class Runner::Strategy::Poseidon < Runner::Strategy
     case response.status
       when 200
         response_body = parse response
-        execution_environments = response_body[:executionEnvironments]
 
-        if execution_environments.nil?
+        if response_body.key? :executionEnvironments
           raise(Runner::Error::UnexpectedResponse.new("Could not get the list of execution environments in Poseidon, got response: #{response.as_json}"))
         else
-          execution_environments
+          response_body[:executionEnvironments] || []
         end
       else
         handle_error response