Stop tokenizing line when the same rule is pushed more than once

Previously Rails classes would infinitly loop if the Ruby on Rails
grammar was loaded but the Ruby grammar had not been. This occurred
because a rule was continually pushing itself on the stack but never
advancing.

Now if the position does not advance and the last two rules in the
stack have the same scope the last rule is popped and the entire line
is tokenized with the current scopes.

Closes #524 #486

spec/app/text-mate-grammar-spec.coffee

@@ -488,6 +488,29 @@ describe "TextMateGrammar", ->
           expect(tokens[2].value).toBe "SELECT"
           expect(tokens[2].scopes).toEqual ["source.js", "comment.line.double-slash.js", "keyword.other.DML.sql"]
 
+    describe "when the position doesn't advance and rule includes $self and matches itself", ->
+      it "token the entire line using the rule", ->
+        grammar = new TextMateGrammar
+          name: "test"
+          scopeName: "source"
+          repository: {}
+          patterns: [
+            {
+              name: "text"
+              begin: "(?=forever)"
+              end: "whatevs"
+              patterns: [
+                include: "$self"
+              ]
+            }
+          ]
+
+        {tokens} = grammar.tokenizeLine("forever and ever")
+
+        expect(tokens.length).toBe 1
+        expect(tokens[0].value).toBe "forever and ever"
+        expect(tokens[0].scopes).toEqual ["source", "text"]
+
   describe "language-specific integration tests", ->
     lines = null
 

src/app/text-mate-grammar.coffee

@@ -155,9 +155,19 @@ class TextMateGrammar
           ))
         break
 
-      if position == previousPosition and ruleStack.length == previousRuleStackLength
-        console.error("Popping rule because it loops at column #{position} of line '#{line}'", _.clone(ruleStack))
-        ruleStack.pop()
+      if position == previousPosition
+        if ruleStack.length == previousRuleStackLength
+          console.error("Popping rule because it loops at column #{position} of line '#{line}'", _.clone(ruleStack))
+          ruleStack.pop()
+
+        [penultimateRule, lastRule] = ruleStack[-2..]
+        if lastRule? and penultimateRule.scopeName == lastRule.scopeName
+          ruleStack.pop()
+          tokens.push(new Token(
+            value: line[position...line.length]
+            scopes: scopes
+          ))
+          break
 
     ruleStack.forEach (rule) -> rule.clearAnchorPosition()
     { tokens, ruleStack }