fix(default): Check for wrapped nil in filter (#162)

CHANGELOG.md

@@ -9,6 +9,7 @@
 ### Bug Fixes
 
 - Fixed rendering `{{ block.super }}` with several levels of inheritance
+- Fixed checking dictionary values for nil in `default` filter
 
 
 ## 0.10.1

Sources/Filters.swift

@@ -11,7 +11,8 @@ func lowercase(_ value: Any?) -> Any? {
 }
 
 func defaultFilter(value: Any?, arguments: [Any?]) -> Any? {
-  if let value = value {
+  // value can be optional wrapping nil, so this way we check for underlying value
+  if let value = value, String(describing: value) != "nil" {
     return value
   }
 

Tests/StencilTests/FilterSpec.swift

@@ -136,6 +136,14 @@ func testFilter() {
       let result = try template.render(Context(dictionary: [:]))
       try expect(result) == "Hello World"
     }
+    
+    $0.it("checks for underlying nil value correctly") {
+      let template = Template(templateString: "Hello {{ user.name|default:\"anonymous\" }}")
+      let nilName: String? = nil
+      let user: [String: Any?] = ["name": nilName]
+      let result = try template.render(Context(dictionary: ["user": user]))
+      try expect(result) == "Hello anonymous"
+    }
   }
 
   describe("join filter") {