From 53127c2410c29f7cc942a76baa7be97ba65aafda Mon Sep 17 00:00:00 2001
From: k0kubun <k0kubun@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 17 May 2017 11:58:09 +0000
Subject: [PATCH] erb.rb: Don't encode tilde in #url_encode

Based on patch by madeofcode (Mark Dodwell).
[ruby-core:46168] [Bug #6696] [Fix GH-54]

`~` is a unreserved character.
https://tools.ietf.org/html/rfc3986#section-2.3

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58772 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 lib/erb.rb           | 2 +-
 test/erb/test_erb.rb | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/erb.rb b/lib/erb.rb
index ab65ef3be5..ae2bfd0091 100644
--- a/lib/erb.rb
+++ b/lib/erb.rb
@@ -994,7 +994,7 @@ class ERB
     #   Programming%20Ruby%3A%20%20The%20Pragmatic%20Programmer%27s%20Guide
     #
     def url_encode(s)
-      s.to_s.b.gsub(/[^a-zA-Z0-9_\-.]/n) { |m|
+      s.to_s.b.gsub(/[^a-zA-Z0-9_\-.~]/n) { |m|
         sprintf("%%%02X", m.unpack("C")[0])
       }
     end
diff --git a/test/erb/test_erb.rb b/test/erb/test_erb.rb
index 6a07f9c5cb..7a92de3630 100644
--- a/test/erb/test_erb.rb
+++ b/test/erb/test_erb.rb
@@ -464,6 +464,10 @@ EOS
 
     assert_equal("%A5%B5%A5%F3%A5%D7%A5%EB",
                  ERB::Util.url_encode("\xA5\xB5\xA5\xF3\xA5\xD7\xA5\xEB".force_encoding("EUC-JP")))
+
+    assert_equal("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~",
+                 ERB::Util.url_encode("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~"),
+                 "should not escape any unreserved characters, as per RFC3986 Section 2.3")
   end
 
   def test_percent_after_etag