From c14195a0a2e6f9b234cdc247507c2609943498c5 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sun, 13 Jan 2019 11:59:36 +0200
Subject: Fix: undo HTML escaping of code blocks

---
 NEWS                         |  2 ++
 htmlesc.scenario             | 13 +++++++++++++
 yarn.tests/htmlescape.script |  5 +++++
 yarnlib/mdparser.py          |  5 ++++-
 4 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 htmlesc.scenario
 create mode 100755 yarn.tests/htmlescape.script

diff --git a/NEWS b/NEWS
index 215b42a..623a05c 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,8 @@ This file summarizes changes between releases of cmdtest.
 Version 0.32+git, not yet released
 ----------------------------------
 
+* Undo HTML escaping of code blocks done by the Python Markdown
+  parser.
 
 Version 0.32, released 2018-02-24
 ----------------------------------
diff --git a/htmlesc.scenario b/htmlesc.scenario
new file mode 100644
index 0000000..cb80865
--- /dev/null
+++ b/htmlesc.scenario
@@ -0,0 +1,13 @@
+An HTML escaping scenario
+=========================
+
+Test HTML escapes in IMPLEMENTS code. At some point after Debian 9 was
+released, the Python markdown library yarn uses started to HTML escape
+code blocks. This breaks any shell scripts that use redirection. Make
+sure this works.
+
+    SCENARIO html escaping
+    THEN greet
+
+    IMPLEMENTS THEN greet
+    echo hello > /dev/null
diff --git a/yarn.tests/htmlescape.script b/yarn.tests/htmlescape.script
new file mode 100755
index 0000000..b3a7840
--- /dev/null
+++ b/yarn.tests/htmlescape.script
@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -eu
+
+./run-yarn htmlesc.scenario
diff --git a/yarnlib/mdparser.py b/yarnlib/mdparser.py
index 4bd59d3..67851ec 100644
--- a/yarnlib/mdparser.py
+++ b/yarnlib/mdparser.py
@@ -17,6 +17,7 @@
 
 
 import logging
+import HTMLParser
 import markdown
 import StringIO
 from markdown.treeprocessors import Treeprocessor
@@ -40,10 +41,12 @@ class GatherCodeBlocks(Treeprocessor):
         self.blocks = blocks
 
     def run(self, root):
+        h = HTMLParser.HTMLParser()
         for child in root.getchildren():
             if child.tag == 'pre':
                 code = child.find('code')
-                self.blocks.append(code.text)
+                text = h.unescape(code.text)
+                self.blocks.append(text)
         return root
 
 # This is the Python Markdown extension to call the code block
-- 
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