Don't blank pad day of the month when formatting dates

We are currently using `%e` which adds a space before the result if the
digit is a single number. This leads to strings like `February  2, 2016`
which is undesireable. I've opted to replace with 0 padding instead of
removing the padding entirely, to preserve compatibility for those
relying on the fact that the width is constant, and to be consistent
with time formatting.

Fixes #25251.

3 files changed, 21 insertions, 3 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 812e18a253..2842b692e2 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   `Date.to_s` doesn't produce too many spaces. For example, `to_s(:short)`
+    will now produce `01 Feb` instead of ` 1 Feb`.
+
+    Fixes #25251.
+
+    *Sean Griffin*
+
 *   Introduce Module#delegate_missing_to.
 
     When building a decorator, a common pattern emerges:
diff --git a/activesupport/lib/active_support/core_ext/date/conversions.rb b/activesupport/lib/active_support/core_ext/date/conversions.rb
index 9a6d7bb415..6e3b4a89ce 100644
--- a/activesupport/lib/active_support/core_ext/date/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/date/conversions.rb
@@ -5,15 +5,15 @@ require 'active_support/core_ext/module/remove_method'
 
 class Date
   DATE_FORMATS = {
-    :short        => '%e %b',
-    :long         => '%B %e, %Y',
+    :short        => '%d %b',
+    :long         => '%B %d, %Y',
     :db           => '%Y-%m-%d',
     :number       => '%Y%m%d',
     :long_ordinal => lambda { |date|
       day_format = ActiveSupport::Inflector.ordinalize(date.day)
       date.strftime("%B #{day_format}, %Y") # => "April 25th, 2007"
     },
-    :rfc822       => '%e %b %Y',
+    :rfc822       => '%d %b %Y',
     :iso8601      => lambda { |date| date.iso8601 }
   }
 
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
index 8052d38c33..a7219eee31 100644
--- a/activesupport/test/core_ext/date_ext_test.rb
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -30,6 +30,17 @@ class DateExtCalculationsTest < ActiveSupport::TestCase
     assert_equal "2005-02-21",          date.to_s(:iso8601)
   end
 
+  def test_to_s_with_single_digit_day
+    date = Date.new(2005, 2, 1)
+    assert_equal "2005-02-01",          date.to_s
+    assert_equal "01 Feb",              date.to_s(:short)
+    assert_equal "February 01, 2005",   date.to_s(:long)
+    assert_equal "February 1st, 2005",  date.to_s(:long_ordinal)
+    assert_equal "2005-02-01",          date.to_s(:db)
+    assert_equal "01 Feb 2005",         date.to_s(:rfc822)
+    assert_equal "2005-02-01",          date.to_s(:iso8601)
+  end
+
   def test_readable_inspect
     assert_equal "Mon, 21 Feb 2005", Date.new(2005, 2, 21).readable_inspect
     assert_equal Date.new(2005, 2, 21).readable_inspect, Date.new(2005, 2, 21).inspect