Mustachio: update 'current' template when rendering a template (#2497)

Author: srawlins

lib/src/mustachio/renderer_base.dart

@@ -136,12 +136,18 @@ abstract class RendererBase<T> {
   /// The renderer of the parent context, if any, otherwise `null`.
   final RendererBase parent;
 
-  final Template template;
+  /// The current template being rendered.
+  ///
+  /// When rendering a partial, the [context] object, and hence the
+  /// [RendererBase] does not change, only this current template.
+  Template _template;
 
   /// The output buffer into which [context] is rendered, using a template.
   final buffer = StringBuffer();
 
-  RendererBase(this.context, this.parent, this.template);
+  RendererBase(this.context, this.parent, this._template);
+
+  Template get template => _template;
 
   void write(String text) => buffer.write(text);
 
@@ -245,7 +251,11 @@ abstract class RendererBase<T> {
   void partial(Partial node) {
     var key = node.key;
     var partialFile = template.partials[key];
-    renderBlock(template.partialTemplates[partialFile].ast);
+    var partialTemplate = template.partialTemplates[partialFile];
+    var outerTemplate = _template;
+    _template = partialTemplate;
+    renderBlock(partialTemplate.ast);
+    _template = outerTemplate;
   }
 }
 

test/mustachio/renderer_test.dart

@@ -336,6 +336,20 @@ void main() {
     expect(renderBar(bar, barTemplate), equals('Text Partial goodbye'));
   });
 
+  test('Renderer renders a partial which refers to other partials', () async {
+    var barTemplateFile = getFile('/project/bar.mustache')
+      ..writeAsStringSync('Text, {{#foo}}{{>foo.mustache}}{{/foo}}');
+    getFile('/project/foo.mustache')
+        .writeAsStringSync('p1, {{#l1}}{{>foo_l1.mustache}}{{/l1}}');
+    getFile('/project/foo_l1.mustache').writeAsStringSync('p2 {{.}}, ');
+    var barTemplate = await Template.parse(barTemplateFile);
+    var bar = Bar()
+      ..foo = (Foo()
+        ..s1 = 'hello'
+        ..l1 = [1, 2, 3]);
+    expect(renderBar(bar, barTemplate), equals('Text, p1, p2 1, p2 2, p2 3, '));
+  });
+
   test('Renderer renders a partial with a heterogeneous context chain',
       () async {
     var barTemplateFile = getFile('/project/bar.mustache')