Feature #18564
closedAdd Exception#detailed_message
Description
(This ticket is for recording the final spec of #18438)
Proposal¶
I would introduce a method Exception#detailed_message
, and let the default error printer use it instead of Exception#message
to create a error output.
class MyClass < StandardError
def message = "my error!"
def detailed_message(highlight: false, **opt)
super + "\nThis is\nan additional\nmessage"
end
end
raise MyClass
$ ./miniruby test.rb
test.rb:8:in `<main>': my error! (MyClass)
This is
an additional
message
Here is the implementation: https://github.com/ruby/ruby/pull/5516
Spec¶
Exception#detailed_message(highlight: false)
calls #message
and decorates the returned string. It may add the class name of exception and, when highlight
keyword is true, some escape sequences for highlights.
e = RuntimeError.new("my error!")
p e.detailed_message #=> "my error! (RuntimeError)"
p e.detailed_message(highlight: true) #=> "\e[1mmy error! (\e[1;4mRuntimeError\e[m\e[1m)\e[m"
Previously, the default error printer and Exception#full_message
called #message
to get the error message, applied some processing (adding the error class name and adding escape sequences) to the string, and added backtrace. Now, they now use #detailed_message(highlight: Exception.to_tty?)
instead of #message
.
All keyword arguments passed to Exception#full_message
are delegated to detailed_message
.
Motivation¶
The primary motivation is a clean integration of did_you_mean and error_highlight gems.
At the present time, they overrides Exception#to_s
to add their suggestions. However, there are some known problems in this approach:
- It may break some tests to check the result of
Exception#to_s
depending on whether the gems add suggestions or not. - Some Ruby scripts re-raise an exception by
raise e.class, e.message, e.backtrace
, which makes the gems add their suggestion multiple times (currently, the gems ad-hocly check and avoid multiple addition). - Sometimes a user needs to get the original message without their addition. For the sake, did_you_mean provides
Exception#original_message
, but the workaround is not very well known.
This proposal allows the gems to override Exception#detailed_message
. Exception#to_s
is kept as-is, so the above problems will no longer occur.
Also, the proposal allows a user to get a full_message without the suggestions by err.full_message(did_you_mean: false, error_highlight: false)
.
Here is a proof-of-concept patch for did_you_mean and error_highlight: https://gist.github.com/mame/2c34230f11237dc4af64510cb98acdd8 I'll create PRs for the gems after Exception#detailed_message
is merged.
Cooperation needed¶
This change requires application monitoring services such as Sentry, DataDog, ScoutAPM, etc. They need to use Exception#detailed_message(highlight: false)
instead of Exception#message
to log the error messages after Ruby 3.2. Thankfully, @st0012 (Stan Lo) (the maintainer of Sentry's Ruby SDK) and @ivoanjo (Ivo Anjo) and @marcotc (Marco Costa) (the maintainers of Datadog's application monitoring gem) have agreed with this change.
https://bugs.ruby-lang.org/issues/18438#note-1
https://bugs.ruby-lang.org/issues/18438#note-9
@matz (Yukihiro Matsumoto) has already approved this proposal in #18438 . I'll merge my PR in a few days after some reviews.
Updated by mame (Yusuke Endoh) almost 2 years ago
- Status changed from Open to Closed
I think I have already merged the change. Closing.