From 7966895d0dd38ca2c2362640e528933d55686b51 Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Tue, 23 Sep 2008 22:52:46 +0200
Subject: [PATCH] The hopefully final fix for the bug apollo13 spotted earlier.

--HG--
branch : trunk
---
 jinja2/compiler.py     | 20 +++++++++-----------
 tests/test_old_bugs.py | 14 +++++++++++++-
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/jinja2/compiler.py b/jinja2/compiler.py
index f3b8d6d..0686c84 100644
--- a/jinja2/compiler.py
+++ b/jinja2/compiler.py
@@ -138,9 +138,9 @@ class Frame(object):
         # situations.
         self.rootlevel = False
 
-        # An extends statement flags the frame as silent if it occours.
-        # This is used to suppress unwanted output.
-        self.silent = False
+        # in some dynamic inheritance situations the compiler needs to add
+        # write tests around output statements.
+        self.require_output_check = parent and parent.require_output_check
 
         # inside some tags we are using a buffer rather than yield statements.
         # this for example affects {% filter %} or {% macro %}.  If a frame
@@ -682,6 +682,7 @@ class CodeGenerator(NodeVisitor):
         frame = Frame()
         frame.inspect(node.body)
         frame.toplevel = frame.rootlevel = True
+        frame.require_output_check = have_extends and not self.has_known_extends
         self.indent()
         if have_extends:
             self.writeline('parent_template = None')
@@ -757,7 +758,6 @@ class CodeGenerator(NodeVisitor):
         if not frame.toplevel:
             self.fail('cannot use extend from a non top-level scope',
                       node.lineno)
-        frame.silent = True
 
         # if the number of extends statements in general is zero so
         # far, we don't have to add a check if something extended
@@ -773,12 +773,12 @@ class CodeGenerator(NodeVisitor):
                 self.indent()
             self.writeline('raise TemplateRuntimeError(%r)' %
                            'extended multiple times')
+            self.outdent()
 
             # if we have a known extends already we don't need that code here
             # as we know that the template execution will end here.
             if self.has_known_extends:
                 raise CompilerExit()
-            self.outdent()
 
         self.writeline('parent_template = environment.get_template(', node)
         self.visit(node.template, frame)
@@ -1058,8 +1058,8 @@ class CodeGenerator(NodeVisitor):
 
     def visit_Output(self, node, frame):
         # if we have a known extends statement, we don't output anything
-        # if we are in a silent section
-        if self.has_known_extends and frame.silent:
+        # if we are in a require_output_check section
+        if self.has_known_extends and frame.require_output_check:
             return
 
         if self.environment.finalize:
@@ -1069,11 +1069,9 @@ class CodeGenerator(NodeVisitor):
 
         self.newline(node)
 
-        # if we are not in a block and there was already an extends
-        # statement we have to add a check that disables our yield(s) here
-        # so that they don't appear in the output.
+        # if we are inside a frame that requires output checking, we do so
         outdent_later = False
-        if frame.silent and self.extends_so_far != 0:
+        if frame.require_output_check:
             self.writeline('if parent_template is None:')
             self.indent()
             outdent_later = True
diff --git a/tests/test_old_bugs.py b/tests/test_old_bugs.py
index 08db225..62a9cd6 100644
--- a/tests/test_old_bugs.py
+++ b/tests/test_old_bugs.py
@@ -8,7 +8,8 @@
     :copyright: Copyright 2008 by Armin Ronacher.
     :license: BSD.
 """
-from jinja2 import Environment
+from jinja2 import Environment, DictLoader
+
 
 def test_keyword_folding():
     env = Environment()
@@ -16,3 +17,14 @@ def test_keyword_folding():
     assert env.from_string("{{ 'test'|testing(some='stuff') }}") \
            .render() == 'teststuff'
 
+
+def test_extends_output_bugs():
+    env = Environment(loader=DictLoader({
+        'parent.html': '(({% block title %}{% endblock %}))'
+    }))
+
+    t = env.from_string('{% if expr %}{% extends "parent.html" %}{% endif %}'
+                        '[[{% block title %}title{% endblock %}]]'
+                        '{% for item in [1, 2, 3] %}({{ item }}){% endfor %}')
+    assert t.render(expr=False) == '[[title]](1)(2)(3)'
+    assert t.render(expr=True) == '((title))'
-- 
2.26.2