[Haml] Fix some form_tag nuttiness.

Closes gh-227

doc-src/HAML_CHANGELOG.md

@@ -11,6 +11,9 @@
 * Fix parsing of `if` and `case` statements whose values were assigned to variables.
   This is still bad style, though.
 
+* Fix `form_for` and `form_tag` when they're passed a block that
+  returns a string in a helper.
+
 ## 3.0.15
 
 [Tagged on GitHub](http://github.com/nex3/haml/commit/3.0.15).

lib/haml/helpers/action_view_mods.rb

@@ -140,15 +140,16 @@ def content_tag(*args)
       module FormTagHelper
         def form_tag_with_haml(url_for_options = {}, options = {}, *parameters_for_url, &proc)
           if is_haml?
-            if block_given?
+            wrap_block = block_given? && block_is_haml?(proc)
+            if wrap_block
               oldproc = proc
               proc = haml_bind_proc do |*args|
                 concat "\n"
                 with_tabs(1) {oldproc.call(*args)}
               end
             end
             res = form_tag_without_haml(url_for_options, options, *parameters_for_url, &proc) + "\n"
-            res << "\n" if block_given?
+            res << "\n" if wrap_block
             res
           else
             form_tag_without_haml(url_for_options, options, *parameters_for_url, &proc)
@@ -160,12 +161,13 @@ def form_tag_with_haml(url_for_options = {}, options = {}, *parameters_for_url,
 
       module FormHelper
         def form_for_with_haml(object_name, *args, &proc)
-          if block_given? && is_haml?
+          wrap_block = block_given? && is_haml? && block_is_haml?(proc)
+          if wrap_block
             oldproc = proc
             proc = proc {|*args| with_tabs(1) {oldproc.call(*args)}}
           end
           res = form_for_without_haml(object_name, *args, &proc)
-          res << "\n" if block_given? && is_haml?
+          res << "\n" if wrap_block
           res
         end
         alias_method :form_for_without_haml, :form_for
@@ -191,7 +193,8 @@ def fragment_for_with_haml(*args, &block)
       module FormTagHelper
         def form_tag_with_haml(url_for_options = {}, options = {}, *parameters_for_url, &proc)
           if is_haml?
-            if block_given?
+            wrap_block = block_given? && block_is_haml?(proc)
+            if wrap_block
               oldproc = proc
               proc = haml_bind_proc do |*args|
                 concat "\n"
@@ -218,7 +221,8 @@ def form_tag_with_haml(url_for_options = {}, options = {}, *parameters_for_url,
 
       module FormHelper
         def form_for_with_haml(object_name, *args, &proc)
-          if block_given? && is_haml?
+          wrap_block = block_given? && is_haml? && block_is_haml?(proc)
+          if wrap_block
             oldproc = proc
             proc = haml_bind_proc do |*args|
               tab_up
@@ -229,7 +233,7 @@ def form_for_with_haml(object_name, *args, &proc)
             concat haml_indent
           end
           form_for_without_haml(object_name, *args, &proc)
-          concat "\n" if block_given? && is_haml?
+          concat "\n" if wrap_block
           Haml::Helpers::ErrorReturn.new("form_for") if is_haml?
         end
         alias_method :form_for_without_haml, :form_for

test/haml/helper_test.rb

@@ -5,6 +5,10 @@ class ActionView::Base
   def nested_tag
     content_tag(:span) {content_tag(:div) {"something"}}
   end
+
+  def wacky_form
+    form_tag("/foo") {"bar"}
+  end
 end
 
 module Haml::Helpers
@@ -176,6 +180,15 @@ def @base.protect_against_forgery?; false; end
 HAML
   end
 
+  def test_form_tag_in_helper_with_string_block
+    def @base.protect_against_forgery?; false; end
+    assert_equal(<<HTML, render(<<HAML, :action_view))
+<form #{rails_form_attr}action="/foo" method="post">#{rails_form_opener}bar</form>
+HTML
+#{rails_block_helper_char} wacky_form
+HAML
+  end
+
   def test_haml_tag_name_attribute_with_id
     assert_equal("<p id='some_id'></p>\n", render("- haml_tag 'p#some_id'"))
   end