Fix DRb specs that were failing for me locally.

As the comment explains, I have had to configure my network
adapter in a non-standard way, and it causes
`IPSocket.getaddress(Socket.gethostname)` to raise an error
for me.

A couple of the DRb specs were failing as a result. The use of
`return` from `ensure` caused the error to be ignored (the fact
that `local_drb` was not set caused it to return false). This was
confusing, and using `return` from `ensure` is a horrible practice. I have refactored to avoid the issue, rescuing
errors explicitly.

Author: myronmarston

lib/rspec/core/runner.rb

@@ -150,19 +150,28 @@ def self.installed_at_exit?
       end
 
       # @private
-      # rubocop:disable Lint/EnsureReturn
       def self.running_in_drb?
-        if defined?(DRb) && DRb.current_server && DRb.current_server.alive?
-          require 'socket'
-          require 'uri'
-          local_ipv4 = IPSocket.getaddress(Socket.gethostname)
-          local_drb = ["127.0.0.1", "localhost", local_ipv4].any? { |addr| addr == URI(DRb.current_server.uri).host }
-        end
-      rescue DRb::DRbServerNotFound
-      ensure
-        return local_drb || false
+        return false unless defined?(DRb)
+
+        server = begin
+                   DRb.current_server
+                 rescue DRb::DRbServerNotFound
+                   return false
+                 end
+
+        return false unless server && server.alive?
+
+        require 'socket'
+        require 'uri'
+
+        local_ipv4 = begin
+                       IPSocket.getaddress(Socket.gethostname)
+                     rescue SocketError
+                       return false
+                     end
+
+        ["127.0.0.1", "localhost", local_ipv4].any? { |addr| addr == URI(DRb.current_server.uri).host }
       end
-      # rubocop:enable Lint/EnsureReturn
 
       # @private
       def self.trap_interrupt

spec/rspec/core/runner_spec.rb

@@ -162,6 +162,14 @@ def interrupt
 
       before do
         allow(::DRb).to receive(:current_server) { drb_server }
+
+        # To deal with some network weirdness at my workplace, I had to
+        # configure my network adapter in a non-standard way that causes
+        # `IPSocket.getaddress(Socket.gethostname)` to raise
+        # `SocketError: getaddrinfo: nodename nor servname provided, or not known`
+        # I'm not sure why this happens, but to keep the specs here passing,
+        # I have to stub this out :(.
+        allow(IPSocket).to receive(:getaddress) { "127.0.0.1" }
       end
 
       context "when drb server is started with 127.0.0.1" do
@@ -200,6 +208,20 @@ def interrupt
         it { should be_falsey }
       end
 
+      context "when IPSocket cannot resolve the current hostname" do
+        let(:drb_server) do
+          instance_double(::DRb::DRbServer, :uri => "druby://localhost:0000/", :alive? => true)
+        end
+
+        before do
+          allow(::IPSocket).to receive(:getaddress).and_raise(
+            SocketError, "getaddrinfo: nodename nor servname provided, or not known"
+          )
+        end
+
+        it { should be_falsey }
+      end
+
       context "when no drb server is running" do
         let(:drb_server) do
           raise ::DRb::DRbServerNotFound