error
noun
the state or condition of being wrong in conduct or judgment: the crash
was caused by human error | the money had been paid in error.
| ˈerər |
a mistake: spelling errors | an error of judgment.
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the state or condition of being
wrong in conduct or judgement
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Error (technical): a measure of the
estimated difference between the
observed or calculated value of a
quantity and its true value.
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observed_value != true_value
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Origin: from Middle English errour,
from Latin error (“wandering about”),
infinitive of errō (“to wander, to err”).
error
noun
| ˈerər |
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Wandering
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Friendliness
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Hostility
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STOP
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No content
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End-users
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USERS
1970 - 2017
Succumbed to yet
another Lorum Ipsum
placeholder text.
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Middle-users
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start
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start middle
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start middle end
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start middle end
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start middle end
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No content
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No content
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No content
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No content
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No content
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No content
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ArgumentError
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def explode(code)
puts "#{code} Boom!"
end
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> explode
ArgumentError: wrong number of arguments
(given 0, expected 1)
from (irb):1:in `explode'
from (irb):4
from /…/2.4.0/bin/irb:11:in `'
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> explode
ArgumentError: wrong number of arguments
(given 0, expected 1)
from (irb):1:in `explode'
from (irb):4
from /…/2.4.0/bin/irb:11:in `'
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def explode(code)
puts "#{code} Boom!"
end
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> explode("abcd")
abcd Boom!
=> nil
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def explode(code:)
puts "#{code} Boom!"
end
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:
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> explode
ArgumentError: missing keyword: code
from (irb):9:in `explode'
from (irb):12
from /…/2.4.0/bin/irb:11:in `'
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> explode("abcd")
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> explode("abcd")
ArgumentError: wrong number of arguments
(given 1, expected 0)
from (irb):9:in `explode'
from (irb):13
from /…/2.4.0/bin/irb:11:in `'
> explode("abcd")
ArgumentError: wrong number of arguments
(given 1, expected 0; required keyword: code)
from (irb):1:in `explode'
from (irb):4
from /…/2.5.0-preview1/bin/irb:11:in `'
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No content
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2.5.0
Christmas 2017
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No content
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Help
Ruby
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Joy
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“For me the purpose of life is partly to have joy.
Programmers often feel joy when they can
concentrate on the creative side of programming,
So Ruby is designed to make programmers happy.”
Yukihiro “Matz” Matsumoto
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Rust
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No content
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Elixir
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No content
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Elm
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No content
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Ruby
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irb(main):015:0> expode
NameError: undefined local variable or method `expode' for main:Object
Did you mean? explode
from (irb):15
from /…/2.4.0/bin/irb:11:in `'
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Instant
Recovery
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Handling
Not
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Voodoo
Contextual
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No content
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No content
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No content
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foo.call && bar.call
NoMethodError: undefined method `call' for nil:NilClass
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Did it?
Who
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@foo.call && @bar.call
^----
NoMethodError: The method `call` is undefined on receiver
nil:NilClass
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Context
First,
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@foo.call && @bar.call
^----
NoMethodError: The method `call` is undefined on receiver
nil:NilClass
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Feedback
Then,
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undefined method `call' for nil:NilClass
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The method `call` is undefined
on receiver nil:NilClass
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Clarity
Care &
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Matters
How you say it
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Contextualize
Go forth &
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Elm Street
An error on
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What
happened
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No content
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Context:
type of error
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Where
it happened
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No content
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How
it happened
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No content
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How
to recover!
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No content
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10
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$ bin/rspec spec/ --bisect --seed 36929
Bisect started using options: "spec/ --seed 36929"
Running suite to find failures...
/Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/shell_escape.rb:20:in `escape': undefined method `shellescape' for
# (NoMethodError)
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:154:in `block in load_path'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:154:in `map'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:154:in `load_path'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:26:in `command_for'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:68:in `block in run_locations'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/server.rb:27:in `capture_run_results'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:67:in `run_locations'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/runner.rb:50:in `original_results'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/example_minimizer.rb:114:in `block in prep'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/example_minimizer.rb:151:in `track_duration'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/example_minimizer.rb:113:in `prep'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/example_minimizer.rb:17:in `find_minimal_repro'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/coordinator.rb:37:in `block (2 levels) in bisect'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/server.rb:18:in `run'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/coordinator.rb:32:in `block in bisect'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/reporter.rb:191:in `close_after'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/coordinator.rb:31:in `bisect'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/bisect/coordinator.rb:19:in `bisect_with'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/invocations.rb:32:in `call'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/runner.rb:69:in `run'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/lib/rspec/core/runner.rb:45:in `invoke'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/rspec-core-3.6.0/exe/rspec:4:in `'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/dependencies.rb:287:in `load'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/dependencies.rb:287:in `block in load'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/dependencies.rb:259:in `load_dependency'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/dependencies.rb:287:in `load'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/spring-commands-rspec-1.0.4/lib/spring/commands/rspec.rb:18:in `call'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/nakayoshi_fork-0.0.3/lib/nakayoshi_fork.rb:24:in `fork'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/gems/2.3.0/gems/nakayoshi_fork-0.0.3/lib/nakayoshi_fork.rb:24:in `fork'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Users/olivierlacan/.rbenv/versions/2.3.4/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from -e:1:in `'
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undefined method
`shellescape'
for #
(NoMethodError)
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What
happened
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rspec-core-3.6.0/lib/rspec/core/bisect/
runner.rb:154:in `block in load_path'
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Where
it happened
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Where
it happened
?
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How
it happened
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How
it happened
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How
to recover!
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How
to recover!
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5
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Unclear &
too late
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ERROR: While executing gem ...
(Gem::FilePermissionError)
You don't have write permissions for
the /Library/Ruby/Gems/2.0.0 directory.
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What
happened
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What
happened
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Where
it happened
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Where
it happened
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How
it happened
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How
it happened
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How
to recover!
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How
to recover!
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5
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What’s
missing?
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A way
foward
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context
error
recovery
feedback
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Resolution
Hints
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“A library or application not having a functional
need to rescue a possible error doesn't grant us
license to ignore how confusing that error may be
for the person who ultimately sees it.”
Justin Searls