throw an exception when whitespace is found within an alias keyword

lib/vagrant/environment.rb

@@ -57,6 +57,9 @@ module Vagrant
     # The directory where temporary files for Vagrant go.
     attr_reader :tmp_path
 
+    # File where command line aliases go.
+    attr_reader :aliases_path
+
     # The directory where boxes are stored.
     attr_reader :boxes_path
 
@@ -123,6 +126,7 @@ module Vagrant
       @data_dir   = @home_path.join("data")
       @gems_path  = Vagrant::Bundler.instance.plugin_gem_path
       @tmp_path   = @home_path.join("tmp")
+      @aliases_path = @home_path.join("aliases")
       @machine_index_dir = @data_dir.join("machine-index")
 
       # Prepare the directories

lib/vagrant/errors.rb

@@ -108,6 +108,10 @@ module Vagrant
       error_key(:active_machine_with_different_provider)
     end
 
+    class AliasInvalidError < VagrantError
+      error_key(:alias_invalid_error)
+    end
+
     class BatchMultiError < VagrantError
       error_key(:batch_multi_error)
     end

templates/locales/en.yml

@@ -378,6 +378,12 @@ en:
         Machine name: %{name}
         Active provider: %{active_provider}
         Requested provider: %{requested_provider}
+      alias_invalid_error: |-
+        The defined alias is not valid. Please review the information below
+        to help resolve the issue:
+
+        Alias: %{alias}
+        Message: %{message}
       batch_multi_error: |-
         An error occurred while executing multiple actions in parallel.
         Any errors that occurred are shown below.

test/unit/vagrant/alias_test.rb

@@ -25,6 +25,18 @@ describe Vagrant::Alias do
       end
     end
 
+    it "raises an error on invalid keywords" do
+      keywords = [
+        "keyword with a space = command",
+        "keyword\twith a tab = command",
+        "keyword\nwith a newline = command",
+      ]
+
+      keywords.each do |keyword|
+        expect { interpreter.interpret(keyword) }.to raise_error(Vagrant::Errors::AliasInvalidError)
+      end
+    end
+
     it "properly interprets a simple alias" do
       keyword, command = interpreter.interpret("keyword=command")
 
@@ -45,5 +57,12 @@ describe Vagrant::Alias do
       expect(keyword).to eq("keyword")
       expect(command).to eq("command = command")
     end
+
+    it "allows keywords with non-alpha-numeric characters" do
+      keyword, command = interpreter.interpret("keyword! = command")
+
+      expect(keyword).to eq("keyword!")
+      expect(command).to eq("command")
+    end
   end
 end