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# frozen_string_literal: true
class Pry
class Command
class Wtf < Pry::ClassCommand
match(/wtf([?!]*)/)
group 'Context'
description 'Show the backtrace of the most recent exception.'
options listing: 'wtf?'
banner <<-'BANNER'
Usage: wtf[?|!]
Shows a few lines of the backtrace of the most recent exception (also available
as `_ex_.backtrace`). If you want to see more lines, add more question marks or
exclamation marks.
wtf?
wtf?!???!?!?
# To see the entire backtrace, pass the `-v` or `--verbose` flag.
wtf -v
BANNER
RUBY_FRAME_PATTERN = /\A(?<file>(.+)):(?<line>(\d+))/.freeze
def options(opt)
opt.on :v, :verbose, "Show the full backtrace"
opt.on :c, :code, "Show code corresponding to the backtrace frame"
end
def process
unless pry_instance.last_exception
raise Pry::CommandError, "No most-recent exception"
end
text = ''.dup
unwind_exceptions.each_with_index do |exception, i|
title = (i == 0 ? 'Exception' : 'Caused by')
text << format_header(title, exception)
text << format_backtrace(exception.backtrace)
end
output.puts(text)
end
private
def unwind_exceptions
exception_list = []
exception = pry_instance.last_exception
while exception
exception_list << exception
exception = (exception.cause if exception.respond_to?(:cause))
end
exception_list
end
def format_header(title, exception)
"#{bold(title + ':')} #{exception.class}: #{exception}\n--\n"
end
def format_backtrace(backtrace)
lines = trim_backtrace(backtrace).map do |frame|
next frame unless opts.code?
match = frame.match(RUBY_FRAME_PATTERN)
code = read_line(match[:file], match[:line].to_i)
[bold(frame), code].join("\n")
end
Pry::Code.new(lines.compact, 0, :text).with_line_numbers.to_s
end
def trim_backtrace(backtrace)
return backtrace if opts.verbose?
size_of_backtrace = [captures[0].size, 0.5].max * 10
backtrace.first(size_of_backtrace)
end
def read_line(file, line)
File.open(file, 'r') do |f|
(line - 1).times { f.gets }
f.gets
end
rescue Errno::ENOENT
nil
end
end
Pry::Commands.add_command(Pry::Command::Wtf)
end
end
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