New rule: duplicated when

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Vitalii Elenhaupt 2017-11-18 18:25:11 +02:00
parent 1839ef2ab5
commit 0520774930
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2 changed files with 169 additions and 0 deletions

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require "../../spec_helper"
module Ameba::Rule
describe DuplicatedWhen do
subject = DuplicatedWhen.new
it "passes if there are no duplicated when conditions in the case" do
s = Source.new %(
case x
when "first"
do_something
when "second"
do_something_else
end
case x
when Integer then :one
when Int32, String then :two
end
case {value1, value2}
when {0, _}
when {_, 0}
end
case x
when .odd?
when .even?
end
case
when Integer then :one
when Integer | String then :two
end
case x
when :one
when "one"
end
case {value1, value2}
when {String, String}
end
)
subject.catch(s).should be_valid
end
it "fails if there is a duplicated when condition in the case" do
s = Source.new %(
case x
when .starts_with?("pattern1")
do_something1
when .starts_with?("pattern2")
do_something2
when .starts_with?("pattern1")
do_something3
end
)
subject.catch(s).should_not be_valid
end
it "fails if there are multiple when conditions with nil" do
s = Source.new %(
case x
when nil
say_hello
when nil
say_nothing
end
)
subject.catch(s).should_not be_valid
end
it "fails if there are multiple whens with is_a? conditions" do
s = Source.new %(
case x
when String then say_hello
when Integer then say_nothing
when String then blah
end
)
subject.catch(s).should_not be_valid
end
it "fails if there are duplicated whens but in difference order" do
s = Source.new %(
case x
when String, Integer then something
when Integer then blah
end
)
subject.catch(s).should_not be_valid
end
it "fails if there are duplicated conditions in one when" do
s = Source.new %(
case x
when String, String then something
end
)
subject.catch(s).should_not be_valid
end
it "reports rule, location and message" do
s = Source.new %q(
case x
when "first"
when "first"
end
), "source.cr"
subject.catch(s).should_not be_valid
error = s.errors.first
error.rule.should_not be_nil
error.location.to_s.should eq "source.cr:2:9"
error.message.should eq "Duplicated when conditions in case."
end
end
end

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module Ameba::Rule
# A rule that disallows duplicated when conditions in case.
#
# This is considered invalid:
#
# ```
# case a
# when "first"
# do_something
# when "first"
# do_somehting_else
# end
# ```
#
# And it should be written as follows:
#
# ```
# case a
# when "first"
# do_something
# when "second"
# do_somehting_else
# end
# ```
#
# YAML configuration example:
#
# ```
# DuplicatedWhen:
# Enabled: true
# ```
#
struct DuplicatedWhen < Base
def test(source)
AST::Visitor.new self, source
end
def test(source, node : Crystal::Case)
return unless duplicated_whens?(node.whens)
source.error self, node.location, "Duplicated when conditions in case."
end
private def duplicated_whens?(whens)
whens.map(&.conds.map &.to_s)
.flatten
.group_by(&.itself)
.any? { |_, v| v.size > 1 }
end
end
end