provisioners/ansible(both): Quote host_vars if needed

This patch is based on @subimage's inputs in the related GitHub issue.
Thanks again!

Fix #8597

CHANGELOG.md

@@ -13,6 +13,7 @@ BUG FIXES:
 
 - guests/shell_expand_guest_path : Properly expand guest paths that include relative path alias [GH-8918]
 - hosts/linux: Remove duplicate export folders before writing /etc/exports [GH-8945]
+- provisioners/ansible(both): Add single quotes to the inventory host variables, only when necessary [GH-8597]
 - provisioners/ansible(both): Add the "all:vars" section to the inventory when defined in `groups` option [GH-7730]
 - provisioners/ansible_local: Extra variables are no longer truncated when a dollar ($) character is present [GH-7735]
 - provisioners/file: Align file provisioner functionality on all platforms [GH-8939]

plugins/provisioners/ansible/provisioner/base.rb

@@ -148,7 +148,13 @@ module VagrantPlugins
           end
           s = nil
           if vars.is_a?(Hash)
-            s = vars.each.collect{ |k, v| "#{k}=#{v}" }.join(" ")
+            s = vars.each.collect {
+              |k, v|
+                if v.is_a?(String) && v.include?(' ') && !v.match(/^('|")[^'"]+('|")$/)
+                  v = %Q('#{v}')
+                end
+                "#{k}=#{v}"
+              }.join(" ")
           elsif vars.is_a?(Array)
             s = vars.join(" ")
           elsif vars.is_a?(String)

test/unit/plugins/provisioners/ansible/provisioner_test.rb

@@ -291,11 +291,15 @@ VF
 
       it "adds host variables (given in Hash format) to the generated inventory" do
         config.host_vars = {
-          machine1: {"http_port" => 80, "comments" => "'some text with spaces'"}
+          machine1: {
+            "http_port" => 80,
+            "comments" => "'some text with spaces and quotes'",
+            "description" => "text with spaces but no quotes",
+          }
         }
         expect(Vagrant::Util::Subprocess).to receive(:execute).with(any_args) {
           inventory_content = File.read(generated_inventory_file)
-          expect(inventory_content).to match("^" + Regexp.quote(machine.name) + ".+http_port=80 comments='some text with spaces'$")
+          expect(inventory_content).to match("^" + Regexp.quote(machine.name) + ".+http_port=80 comments='some text with spaces and quotes' description='text with spaces but no quotes'")
         }.and_return(default_execute_result)
       end
 

website/source/docs/provisioning/ansible_common.html.md

@@ -93,7 +93,7 @@ Some of these options are for advanced usage only and should not be used unless
     ansible.host_vars = {
       "host1" => {"http_port" => 80,
                   "maxRequestsPerChild" => 808},
-                  "comments" => "'text with spaces'",
+                  "comments" => "text with spaces",
       "host2" => {"http_port" => 303,
                   "maxRequestsPerChild" => 909}
     }