我正在尝试为我的模型验证添加自定义错误消息。见下图：
validates :cost, numericality: { greater_than_or_equal_to: 0, message: :custom_error }我的 en.yml 看起来像这样：
en:
activerecord:
errors:
messages:
custom_error: "some error translation"从我读过的所有内容来看，这应该有效。但是，它仅在某些情况下有效。如果我执行以下操作，它似乎有效：
a = Item.new
a.valid?
# false
a.errors.messages
# { :cost=>["some error translation"]}在救援块中，我发现了该错误并打印了如下所示的消息：
def subtract_costs
item.cost: -10
item.valid?
puts "error: #{item.errors.messages}"
# Above outputs "error: {:cost=>["some error translation"]}"
rescue StandardError => error
puts error.message
# Above outputs "Validation failed:"
end该消息总是传给 Validation failed: 。有谁知道什么可能导致错误消息为空白？我的项目中没有任何其他本地人或翻译。
回答1
编辑：我看到这里还有另一个问题。你的救援块有点混乱。在你的救援块中，你救援的是 Rails 运行时错误，而不是模型验证错误（除非你使用了 #save! 或 #update! ，它们通过引发模型验证错误将其转变为运行时错误）。所以 error 在那种情况下是一个运行时错误，它不是为了携带模型验证错误的措辞而设计的。
所以你创造了一种“它不起作用”的情况，但在那种情况下它不应该起作用。这应该更清楚：
def subtract_costs
item.cost = -10
item.valid?
puts "error: #{item.errors.messages}" # outputs "error: {:cost=>["some error translation"]}"
puts item.errors.class.name
rescue StandardError => error
puts error.message # outputs "Validation failed:"
puts error.class.name
end您没有正确查找 EN 语言环境消息。你会这样做：
validates :cost,
numericality: { greater_than_or_equal_to: 0,
message: I18n.t('activerecord.errors.messages.custom_error') }现在有一些方法可以完全避免在验证器上设置消息，但您需要将消息放在正确的位置。这是您的 EN 语言环境文件中的正确位置/层次结构。这是您的特定消息的正确位置：
en:
errors:
messages:
greater_than_or_equal_to: 'some error translation'一般来说，这里是放置自定义验证错误消息（以及我喜欢的措辞）的地方。
en:
errors:
format: "%{message}"
messages:
accepted: "The %{attribute} was not accepted; please accept the %{attribute}."
blank: "The provided %{attribute} is blank; please enter a non-blank %{attribute}."
confirmation: "The provided %{attribute} does not match the corresponding entry; please re-check this entry against the original."
empty: "The provided %{attribute} is empty; please enter a non-empty %{attribute}."
equal_to: "The provided %{attribute} is incorrect; please enter exactly %{count}."
even: "The provided %{attribute} is odd; please enter an even %{attribute}."
exclusion: "The provided %{attribute} is reserved; please enter a different %{attribute}."
greater_than: "The provided %{attribute} is too small; please provide a different %{attribute} greater than %{count}."
greater_than_or_equal_to: "The provided %{attribute} is too small; please provide a different %{attribute} greater than or equal to %{count}."
inclusion: "The chosen %{attribute} is not available; please choose an available option." # Rails 4 and prior.
inclusion_of: "The chosen %{attribute} is not available; please choose an available option." # Rails 5 and later.
invalid: "The provided %{attribute} is invalid; please enter a valid %{attribute}."
in_between: "The provided %{attribute} is outside of the accepted range; please enter a different %{attribute} within the range of %{min} to %{max}."
less_than: "The provided %{attribute} is too large; please provide a different %{attribute} less than %{count}."
less_than_or_equal_to: "The provided %{attribute} is too large; please provide a different %{attribute} less than or equal to %{count}."
not_a_number: "The provided %{attribute} is not numeric; please enter a numeric %{attribute}."
odd: "The provided %{attribute} is even; please enter an odd %{attribute}."
record_invalid: "The %{attribute} is invalid. %{errors}"
spoofed_media_type: "The provided %{attribute} is invalid (often due to an incorrect file extension); please provide a valid %{attribute}, including an appropriate file extension."
too_long: "The provided %{attribute} contains more than the %{count} available characters; please shorten the entry."
too_short: "The provided %{attribute} contains fewer than the %{count} required characters; please lengthen the entry."
taken: "The provided %{attribute} is already taken; please enter a different %{attribute}."
wrong_length: "The provided %{attribute} contains the wrong amount of characters; please adjust the entry to exactly %{count} characters."