From a38fd1bb8b15e5de44e322b3345d0b5c29d5bf6b Mon Sep 17 00:00:00 2001
From: Isaac Muse <faceless.shop@gmail.com>
Date: Tue, 30 Oct 2018 09:09:40 -0600
Subject: Collapse all whitespace in reference ids (#743)

Previously only newlines preceded by whitespace were collapsed. Fixes #742.
---
 docs/change_log/release-3.1.md         |  1 +
 markdown/inlinepatterns.py             |  2 +-
 tests/test_syntax/inline/test_links.py | 37 ++++++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/docs/change_log/release-3.1.md b/docs/change_log/release-3.1.md
index c05d70f..0e8e2b1 100644
--- a/docs/change_log/release-3.1.md
+++ b/docs/change_log/release-3.1.md
@@ -35,3 +35,4 @@ The following bug fixes are included in the 3.1 release:
 * Block level elements are defined per instance, not as class attributes
   (#731).
 * Double escaping of block code has been eliminated (#725).
+* Problems with newlines in references has been fixed (#742).
diff --git a/markdown/inlinepatterns.py b/markdown/inlinepatterns.py
index 3d3e65f..dc502c2 100644
--- a/markdown/inlinepatterns.py
+++ b/markdown/inlinepatterns.py
@@ -617,7 +617,7 @@ class ImageInlineProcessor(LinkInlineProcessor):
 
 class ReferenceInlineProcessor(LinkInlineProcessor):
     """ Match to a stored reference and return link element. """
-    NEWLINE_CLEANUP_RE = re.compile(r'[ ]?\n', re.MULTILINE)
+    NEWLINE_CLEANUP_RE = re.compile(r'\s+', re.MULTILINE)
 
     RE_LINK = re.compile(r'\s?\[([^\]]*)\]', re.DOTALL | re.UNICODE)
 
diff --git a/tests/test_syntax/inline/test_links.py b/tests/test_syntax/inline/test_links.py
index e147c82..988e041 100644
--- a/tests/test_syntax/inline/test_links.py
+++ b/tests/test_syntax/inline/test_links.py
@@ -134,3 +134,40 @@ class TestAdvancedLinks(TestCase):
             '[title](http://example.com/?a=1&#x26;b=2)',
             '<p><a href="http://example.com/?a=1&#x26;b=2">title</a></p>'
         )
+
+    def test_reference_newlines(self):
+        """Test reference id whitespace cleanup."""
+
+        self.assertMarkdownRenders(
+            self.dedent(
+                """
+                Two things:
+
+                 - I would like to tell you about the [code of
+                   conduct][] we are using in this project.
+                 - Only one in fact.
+
+                [code of conduct]: https://github.com/Python-Markdown/markdown/blob/master/CODE_OF_CONDUCT.md
+                """
+            ),
+            '<p>Two things:</p>\n<ul>\n<li>I would like to tell you about the '
+            '<a href="https://github.com/Python-Markdown/markdown/blob/master/CODE_OF_CONDUCT.md">code of\n'
+            '   conduct</a> we are using in this project.</li>\n<li>Only one in fact.</li>\n</ul>'
+        )
+
+    def test_reference_across_blocks(self):
+        """Test references across blocks."""
+
+        self.assertMarkdownRenders(
+            self.dedent(
+                """
+                I would like to tell you about the [code of
+
+                conduct][] we are using in this project.
+
+                [code of conduct]: https://github.com/Python-Markdown/markdown/blob/master/CODE_OF_CONDUCT.md
+                """
+            ),
+            '<p>I would like to tell you about the [code of</p>\n'
+            '<p>conduct][] we are using in this project.</p>'
+        )
-- 
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