Default ranges to empty array when no edit session

Previously an exception would be thrown if a '/' pattern was evaluated
when there was no active edit session.

src/packages/command-panel/lib/commands/composite-command.coffee

@@ -6,7 +6,7 @@ class CompositeCommand
   constructor: (@subcommands) ->
 
   execute: (project, editSession) ->
-    currentRanges = editSession?.getSelectedBufferRanges()
+    currentRanges = editSession?.getSelectedBufferRanges() ? []
     @executeCommands(@subcommands, project, editSession, currentRanges)
 
   executeCommands: (commands, project, editSession, ranges) ->
@@ -60,4 +60,3 @@ class CompositeCommand
 
   isRelativeAddress: ->
     _.all(@subcommands, (command) -> command.isAddress() and command.isRelative())
-

src/packages/command-panel/spec/command-interpreter-spec.coffee

@@ -205,6 +205,17 @@ describe "CommandInterpreter", ->
         runs ->
           expect(interpreter.lastRelativeAddress.subcommands[0].regex.toString()).toEqual "/Array/"
 
+      describe "when there is no active edit session", ->
+        it "returns no error messages and does not throw an error", ->
+          errorMessages = null
+
+          waitsForPromise ->
+            interpreter.eval('/something').done (results) ->
+              {errorMessages} = results
+
+          runs ->
+            expect(errorMessages.length).toBe 0
+
     describe "address range", ->
       describe "when two addresses are specified", ->
         it "selects from the begining of the left address to the end of the right address", ->