Always perform division on numbers returned by functions.

Closes sass#973

Author: nex3

doc-src/SASS_CHANGELOG.md

@@ -3,6 +3,11 @@
 * Table of contents
 {:toc}
 
+## 3.2.13 (Unreleased)
+
+* Numbers returned by user-defined functions now trigger division, just like
+  numbers stored in variables.
+
 ## 3.2.12
 
 * Add a couple missing `require`s, fixing some load errors, especially when

doc-src/SASS_REFERENCE.md

@@ -761,7 +761,7 @@ However, there are three situations where the `/` will be interpreted as divisio
 These cover the vast majority of cases where division is actually used.
 They are:
 
-1. If the value, or any part of it, is stored in a variable.
+1. If the value, or any part of it, is stored in a variable or returned by a function.
 2. If the value is surrounded by parentheses.
 3. If the value is used as part of another arithmetic expression.
 
@@ -771,6 +771,7 @@ For example:
       font: 10px/8px;             // Plain CSS, no division
       $width: 1000px;
       width: $width/2;            // Uses a variable, does division
+      width: round(1.5)/2;        // Uses a function, does division
       height: (500px/2);          // Uses parentheses, does division
       margin-left: 5px + 8px/2px; // Uses +, does division
     }

lib/sass/script/funcall.rb

@@ -100,16 +100,17 @@ def _perform(environment)
         splat = @splat.perform(environment) if @splat
         if fn = environment.function(@name)
           keywords = Sass::Util.map_hash(@keywords) {|k, v| [k, v.perform(environment)]}
-          return perform_sass_fn(fn, args, keywords, splat)
+          return without_original(perform_sass_fn(fn, args, keywords, splat))
         end
 
         ruby_name = @name.tr('-', '_')
         args = construct_ruby_args(ruby_name, args, splat, environment)
 
         unless Functions.callable?(ruby_name)
-          opts(to_literal(args))
+          without_original(opts(to_literal(args)))
         else
-          opts(Functions::EvaluationContext.new(environment.options).send(ruby_name, *args))
+          without_original(opts(Functions::EvaluationContext.new(environment.options)
+              .send(ruby_name, *args)))
         end
       rescue ArgumentError => e
         message = e.message
@@ -170,6 +171,13 @@ def to_literal(args)
 
       private
 
+      def without_original(value)
+        return value unless value.is_a?(Number)
+        value = value.dup
+        value.original = nil
+        return value
+      end
+
       def construct_ruby_args(name, args, splat, environment)
         args += splat.to_a if splat
 

test/sass/script_test.rb

@@ -510,6 +510,30 @@ def test_boolean_ops_short_circuit
 
   # Regression Tests
 
+  def test_user_defined_function_forces_division
+    assert_equal(<<CSS, render(<<SASS))
+a {
+  b: 10px; }
+CSS
+@function foo()
+  @return 20px
+
+a
+  b: (foo() / 2)
+SASS
+
+    assert_equal(<<CSS, render(<<SASS))
+a {
+  b: 10px; }
+CSS
+@function foo()
+  @return 20px
+
+a
+  b: foo() / 2
+SASS
+end
+
   def test_funcall_has_higher_precedence_than_color_name
     assert_equal "teal(12)", resolve("teal(12)")
     assert_equal "tealbang(12)", resolve("tealbang(12)")