From 393dc88a10534083353e4851d45759115d9dada0 Mon Sep 17 00:00:00 2001
From: Kyle Fuller <kyle@fuller.li>
Date: Sun, 27 Nov 2016 04:22:37 +0000
Subject: [PATCH] fix(extends): Support multiple extends

Fixes #60
---
 CHANGELOG.md                                 |  3 +++
 Sources/Inheritence.swift                    | 27 ++++++++++++++------
 Tests/StencilTests/InheritenceSpec.swift     |  6 +++++
 Tests/StencilTests/fixtures/child-child.html |  2 ++
 4 files changed, 30 insertions(+), 8 deletions(-)
 create mode 100644 Tests/StencilTests/fixtures/child-child.html

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2afa164..769ab2d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,9 @@
   index will now resolve to `nil` instead of causing a crash.
   [#72](https://github.com/kylef/Stencil/issues/72)
 
+- Templates can now extend templates that extend other templates.
+  [#60](https://github.com/kylef/Stencil/issues/60)
+
 
 ## 0.6.0
 
diff --git a/Sources/Inheritence.swift b/Sources/Inheritence.swift
index fd3ef73..d2c1299 100644
--- a/Sources/Inheritence.swift
+++ b/Sources/Inheritence.swift
@@ -1,9 +1,9 @@
 class BlockContext {
   class var contextKey: String { return "block_context" }
 
-  var blocks: [String:BlockNode]
+  var blocks: [String: BlockNode]
 
-  init(blocks: [String:BlockNode]) {
+  init(blocks: [String: BlockNode]) {
     self.blocks = blocks
   }
 
@@ -42,10 +42,9 @@ class ExtendsNode : NodeType {
       throw TemplateSyntaxError("'extends' cannot appear more than once in the same template")
     }
 
-    let blockNodes = parsedNodes.filter { node in node is BlockNode }
+    let blockNodes = parsedNodes.flatMap { $0 as? BlockNode }
 
-    let nodes = blockNodes.reduce([String:BlockNode]()) { (accumulator, node:NodeType) -> [String:BlockNode] in
-      let node = (node as! BlockNode)
+    let nodes = blockNodes.reduce([String: BlockNode]()) { (accumulator, node) -> [String: BlockNode] in
       var dict = accumulator
       dict[node.name] = node
       return dict
@@ -69,11 +68,23 @@ class ExtendsNode : NodeType {
     }
 
     guard let template = loader.loadTemplate(templateName) else {
-      let paths:String = loader.paths.map { $0.description }.joined(separator: ", ")
+      let paths: String = loader.paths.map { $0.description }.joined(separator: ", ")
       throw TemplateSyntaxError("'\(templateName)' template not found in \(paths)")
     }
 
-    let blockContext = BlockContext(blocks: blocks)
+    let blockContext: BlockContext
+    if let context = context[BlockContext.contextKey] as? BlockContext {
+      blockContext = context
+
+      for (key, value) in blocks {
+        if !blockContext.blocks.keys.contains(key) {
+          blockContext.blocks[key] = value
+        }
+      }
+    } else {
+      blockContext = BlockContext(blocks: blocks)
+    }
+
     return try context.push(dictionary: [BlockContext.contextKey: blockContext]) {
       return try template.render(context)
     }
@@ -89,7 +100,7 @@ class BlockNode : NodeType {
     let bits = token.components()
 
     guard bits.count == 2 else {
-      throw TemplateSyntaxError("'block' tag takes one argument, the template file to be included")
+      throw TemplateSyntaxError("'block' tag takes one argument, the block name")
     }
 
     let blockName = bits[1]
diff --git a/Tests/StencilTests/InheritenceSpec.swift b/Tests/StencilTests/InheritenceSpec.swift
index accd15a..663161d 100644
--- a/Tests/StencilTests/InheritenceSpec.swift
+++ b/Tests/StencilTests/InheritenceSpec.swift
@@ -13,5 +13,11 @@ func testInheritence() {
       let template = loader.loadTemplate("child.html")
       try expect(try template?.render(context)) == "Header\nChild"
     }
+
+    $0.it("can inherit from another template inheriting from another template") {
+      let context = Context(dictionary: ["loader": loader])
+      let template = loader.loadTemplate("child-child.html")
+      try expect(try template?.render(context)) == "Child Child Header\nChild"
+    }
   }
 }
diff --git a/Tests/StencilTests/fixtures/child-child.html b/Tests/StencilTests/fixtures/child-child.html
new file mode 100644
index 0000000..5bb924e
--- /dev/null
+++ b/Tests/StencilTests/fixtures/child-child.html
@@ -0,0 +1,2 @@
+{% extends "child.html" %}
+{% block header %}Child Child Header{% endblock %}