Add ability to set up transitions without specifying from - these will allow transitioning from ANY state

lib/aasm/supporting_classes/event.rb

@@ -13,34 +13,11 @@ module AASM
       # executes the transition guards to determine if a transition is even
       # an option given current conditions.
       def may_fire?(obj, to_state=nil, *args)
-        transitions = @transitions.select { |t| t.from == obj.aasm_current_state }
+        _fire(obj, true, to_state, *args) # true indicates test firing
-        return false if transitions.size == 0
-
-        result = false
-        transitions.each do |transition|
-          next if to_state and !Array(transition.to).include?(to_state)
-          if transition.perform(obj, *args)
-            result = true
-            break
-          end
-        end
-        result
       end
   
       def fire(obj, to_state=nil, *args)
-        transitions = @transitions.select { |t| t.from == obj.aasm_current_state }
+        _fire(obj, false, to_state, *args) # false indicates this is not a test (fire!)
-        return nil if transitions.size == 0
-
-        next_state = nil
-        transitions.each do |transition|
-          next if to_state and !Array(transition.to).include?(to_state)
-          if transition.perform(obj, *args)
-            next_state = to_state || Array(transition.to).first
-            transition.execute(obj, *args)
-            break
-          end
-        end
-        next_state
       end
 
       def transitions_from_state?(state)
@@ -112,6 +89,32 @@ module AASM
         self
       end
 
+      # Execute if test? == false, otherwise return true/false depending on whether it would fire
+      def _fire(obj, test, to_state=nil, *args)
+        if @transitions.map(&:from).any?
+          transitions = @transitions.select { |t| t.from == obj.aasm_current_state }
+          return nil if transitions.size == 0
+        else
+          transitions = @transitions
+        end
+
+        result = test ? false : nil
+        transitions.each do |transition|
+          next if to_state and !Array(transition.to).include?(to_state)
+          if transition.perform(obj, *args)
+            if test
+              result = true
+            else
+              result = to_state || Array(transition.to).first
+              transition.execute(obj, *args)
+            end
+
+            break
+          end
+        end
+        result
+      end
+
       def _fire_callbacks(action, record)
         case action
           when Symbol, String
@@ -122,9 +125,12 @@ module AASM
       end
 
       def transitions(trans_opts)
+        # Create a separate transition for each from state to the given state
         Array(trans_opts[:from]).each do |s|
           @transitions << AASM::SupportingClasses::StateTransition.new(trans_opts.merge({:from => s.to_sym}))
         end
+        # Create a transition if to is specified without from (transitions from ANY state)
+        @transitions << AASM::SupportingClasses::StateTransition.new(trans_opts) if @transitions.empty? && trans_opts[:to]
       end
 
     end

spec/models/silencer.rb

@@ -9,9 +9,14 @@ class Silencer
     event :cry do
       transitions :from => :silent, :to => :crying
     end
+
     event :smile do
       transitions :from => :crying, :to => :smiling
     end
+
+    event :smile_any do
+      transitions :to => :smiling
+    end
   end
 
 end

spec/unit/state_transition_spec.rb

@@ -20,6 +20,12 @@ describe 'transitions' do
     sub.should be_silent
   end
 
+  it 'should not raise an exception when from is nil even if whiny' do
+    silencer = Silencer.new
+    silencer.smile_any!.should be_true
+    silencer.should be_smiling
+  end
+  
 end
 
 describe AASM::SupportingClasses::StateTransition do