9 files changed, 49 insertions, 36 deletions
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 1c6f340fba..a8d875640e 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,12 @@
+*   Fix `ActiveSupport::TimeZone#strptime`. Now raises `ArgumentError` when the
+    given time doesn't match the format. The error is the same as the one given
+    by Ruby's `Date.strptime`. Previously it raised
+    `NoMethodError: undefined method empty? for nil:NilClass.` due to a bug.
+
+    Fixes #25701.
+
+    *John Gesimondo*
+
 *   `travel/travel_to` travel time helpers, now raise on nested calls, 
      as this can lead to confusing time stubbing.
        
diff --git a/activesupport/lib/active_support/core_ext/class/attribute.rb b/activesupport/lib/active_support/core_ext/class/attribute.rb
index 802d988af2..aa0e2a1a88 100644
--- a/activesupport/lib/active_support/core_ext/class/attribute.rb
+++ b/activesupport/lib/active_support/core_ext/class/attribute.rb
@@ -27,7 +27,7 @@ class Class
   # This matches normal Ruby method inheritance: think of writing an attribute
   # on a subclass as overriding the reader method. However, you need to be aware
   # when using +class_attribute+ with mutable structures as +Array+ or +Hash+.
-  # In such cases, you don't want to do changes in places but use setters:
+  # In such cases, you don't want to do changes in place. Instead use setters:
   #
   #   Base.setting = []
   #   Base.setting                # => []
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index 005ad93b08..f1a0c47c54 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -1,5 +1,6 @@
 require 'erb'
 require 'active_support/core_ext/kernel/singleton_class'
+require 'active_support/multibyte/unicode'
 
 class ERB
   module Util
diff --git a/activesupport/lib/active_support/duration/iso8601_serializer.rb b/activesupport/lib/active_support/duration/iso8601_serializer.rb
index 05c6a083a9..eb8136e208 100644
--- a/activesupport/lib/active_support/duration/iso8601_serializer.rb
+++ b/activesupport/lib/active_support/duration/iso8601_serializer.rb
@@ -12,8 +12,10 @@ module ActiveSupport
 
       # Builds and returns output string.
       def serialize
-        output = 'P'
         parts, sign = normalize
+        return "PT0S".freeze if parts.empty?
+
+        output = 'P'
         output << "#{parts[:years]}Y"   if parts.key?(:years)
         output << "#{parts[:months]}M"  if parts.key?(:months)
         output << "#{parts[:weeks]}W"   if parts.key?(:weeks)
diff --git a/activesupport/lib/active_support/lazy_load_hooks.rb b/activesupport/lib/active_support/lazy_load_hooks.rb
index e2b8f0f648..67b54b45ea 100644
--- a/activesupport/lib/active_support/lazy_load_hooks.rb
+++ b/activesupport/lib/active_support/lazy_load_hooks.rb
@@ -20,29 +20,37 @@ module ActiveSupport
   # +activerecord/lib/active_record/base.rb+ is:
   #
   #   ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Base)
-  @load_hooks = Hash.new { |h,k| h[k] = [] }
-  @loaded = Hash.new { |h,k| h[k] = [] }
-
-  def self.on_load(name, options = {}, &block)
-    @loaded[name].each do |base|
-      execute_hook(base, options, block)
+  module LazyLoadHooks
+    def self.extended(base) # :nodoc:
+      base.class_eval do
+        @load_hooks = Hash.new { |h,k| h[k] = [] }
+        @loaded     = Hash.new { |h,k| h[k] = [] }
+      end
     end
 
-    @load_hooks[name] << [block, options]
-  end
+    def on_load(name, options = {}, &block)
+      @loaded[name].each do |base|
+        execute_hook(base, options, block)
+      end
 
-  def self.execute_hook(base, options, block)
-    if options[:yield]
-      block.call(base)
-    else
-      base.instance_eval(&block)
+      @load_hooks[name] << [block, options]
     end
-  end
 
-  def self.run_load_hooks(name, base = Object)
-    @loaded[name] << base
-    @load_hooks[name].each do |hook, options|
-      execute_hook(base, options, hook)
+    def execute_hook(base, options, block)
+      if options[:yield]
+        block.call(base)
+      else
+        base.instance_eval(&block)
+      end
+    end
+
+    def run_load_hooks(name, base = Object)
+      @loaded[name] << base
+      @load_hooks[name].each do |hook, options|
+        execute_hook(base, options, hook)
+      end
     end
   end
+
+  extend LazyLoadHooks
 end
diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
index 19420cee5e..eb89a6d4c5 100644
--- a/activesupport/lib/active_support/values/time_zone.rb
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -447,6 +447,7 @@ module ActiveSupport
 
     private
       def parts_to_time(parts, now)
+        raise ArgumentError, "invalid date" if parts.nil?
         return if parts.empty?
 
         time = Time.new(
diff --git a/activesupport/test/core_ext/duration_test.rb b/activesupport/test/core_ext/duration_test.rb
index 502e2811fa..a24915dfef 100644
--- a/activesupport/test/core_ext/duration_test.rb
+++ b/activesupport/test/core_ext/duration_test.rb
@@ -279,6 +279,7 @@ class DurationTest < ActiveSupport::TestCase
       ['PT1S',          1.second                         ],
       ['PT1.4S',        (1.4).seconds                    ],
       ['P1Y1M1DT1H',    1.year + 1.month + 1.day + 1.hour],
+      ['PT0S',          0.minutes                        ],
     ]
     expectations.each do |expected_output, duration|
       assert_equal expected_output, duration.iso8601, expected_output.inspect
diff --git a/activesupport/test/load_paths_test.rb b/activesupport/test/load_paths_test.rb
deleted file mode 100644
index ac617a9fd8..0000000000
--- a/activesupport/test/load_paths_test.rb
+++ /dev/null
@@ -1,16 +0,0 @@
-require 'abstract_unit'
-
-class LoadPathsTest < ActiveSupport::TestCase
-  def test_uniq_load_paths
-    load_paths_count = $LOAD_PATH.inject({}) { |paths, path|
-      expanded_path = File.expand_path(path)
-      paths[expanded_path] ||= 0
-      paths[expanded_path] += 1
-      paths
-    }
-    load_paths_count[File.expand_path('../../lib', __FILE__)] -= 1
-
-    load_paths_count.select! { |k, v| v > 1 }
-    assert load_paths_count.empty?, load_paths_count.inspect
-  end
-end
diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
index a15d5c6a0e..76cbb5ce8b 100644
--- a/activesupport/test/time_zone_test.rb
+++ b/activesupport/test/time_zone_test.rb
@@ -388,6 +388,13 @@ class TimeZoneTest < ActiveSupport::TestCase
     end
   end
 
+  def test_strptime_with_malformed_string
+    with_env_tz 'US/Eastern' do
+      zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+      assert_raise(ArgumentError) { zone.strptime('1999-12-31', '%Y/%m/%d') }
+    end
+  end
+
   def test_utc_offset_lazy_loaded_from_tzinfo_when_not_passed_in_to_initialize
     tzinfo = TZInfo::Timezone.get('America/New_York')
     zone = ActiveSupport::TimeZone.create(tzinfo.name, nil, tzinfo)