Merge branch 'master' into laurocaetano-fix_send_file

* master: (536 commits)
  doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]
  Restore DATABASE_URL even if it's nil in connection_handler test
  [ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
  Ensure Active Record connection consistency
  Revert "ask the fixture set for the sql statements"
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
  Adding Hash#compact and Hash#compact! methods
  MySQL version 4.1 was EOL on December 31, 2009 We should at least recommend modern versions of MySQL to users.
  clear cache on body close so that cache remains during rendering
  add a more restricted codepath for templates fixes #13390
  refactor generator tests to use block form of Tempfile
  Fix typo [ci skip]
  Move finish_template as the last public method in the generator
  Minor typos fix [ci skip]
  make `change_column_null` reversible. Closes #13576.
  create/drop test and development databases only if RAILS_ENV is nil
  Revert "Speedup String#to"
  typo fix in test name. [ci skip].
  `core_ext/string/access.rb` test what we are documenting.
  Fix typo in image_tag documentation
  ...

Conflicts:
	actionpack/CHANGELOG.md

1 files changed, 11 insertions, 9 deletions

diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
index f35c2be4c2..3d41aa8572 100644
--- a/activesupport/lib/active_support/core_ext/hash/keys.rb
+++ b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -1,5 +1,5 @@
 class Hash
-  # Return a new hash with all keys converted using the block operation.
+  # Returns a new hash with all keys converted using the block operation.
   #
   #  hash = { name: 'Rob', age: '28' }
   #
@@ -22,7 +22,7 @@ class Hash
     self
   end
 
-  # Return a new hash with all keys converted to strings.
+  # Returns a new hash with all keys converted to strings.
   #
   #   hash = { name: 'Rob', age: '28' }
   #
@@ -38,7 +38,7 @@ class Hash
     transform_keys!{ |key| key.to_s }
   end
 
-  # Return a new hash with all keys converted to symbols, as long as
+  # Returns a new hash with all keys converted to symbols, as long as
   # they respond to +to_sym+.
   #
   #   hash = { 'name' => 'Rob', 'age' => '28' }
@@ -61,17 +61,19 @@ class Hash
   # on a mismatch. Note that keys are NOT treated indifferently, meaning if you
   # use strings for keys but assert symbols as keys, this will fail.
   #
-  #   { name: 'Rob', years: '28' }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: years"
-  #   { name: 'Rob', age: '28' }.assert_valid_keys('name', 'age') # => raises "ArgumentError: Unknown key: name"
+  #   { name: 'Rob', years: '28' }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: :years. Valid keys are: :name, :age"
+  #   { name: 'Rob', age: '28' }.assert_valid_keys('name', 'age') # => raises "ArgumentError: Unknown key: :name. Valid keys are: 'name', 'age'"
   #   { name: 'Rob', age: '28' }.assert_valid_keys(:name, :age)   # => passes, raises nothing
   def assert_valid_keys(*valid_keys)
     valid_keys.flatten!
     each_key do |k|
-      raise ArgumentError.new("Unknown key: #{k}") unless valid_keys.include?(k)
+      unless valid_keys.include?(k)
+        raise ArgumentError.new("Unknown key: #{k.inspect}. Valid keys are: #{valid_keys.map(&:inspect).join(', ')}")
+      end
     end
   end
 
-  # Return a new hash with all keys converted by the block operation.
+  # Returns a new hash with all keys converted by the block operation.
   # This includes the keys from the root hash and from all
   # nested hashes.
   #
@@ -98,7 +100,7 @@ class Hash
     self
   end
 
-  # Return a new hash with all keys converted to strings.
+  # Returns a new hash with all keys converted to strings.
   # This includes the keys from the root hash and from all
   # nested hashes.
   #
@@ -117,7 +119,7 @@ class Hash
     deep_transform_keys!{ |key| key.to_s }
   end
 
-  # Return a new hash with all keys converted to symbols, as long as
+  # Returns a new hash with all keys converted to symbols, as long as
   # they respond to +to_sym+. This includes the keys from the root hash
   # and from all nested hashes.
   #