[Fix #4881] Fix a false positive for HashEachMethods when unused argument(s) exists in other blocks
#4883
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…used argument(s) exists in other blocks
Problem
===
`Performance/HashEachMethods` has a false positive for the following code.
```ruby
@h.each do |key, value|
p(key * -value)
end
@h.sum { |key, value| -value }
```
The `each` does not have any unused arguments. `key` and `value` are used. So, this cop should not add an offense for the code.
But the cop adds an offence for the code currently.
This cause is the `sum` has an unused argument, and the argument is named `key`, the name is same as the `each`'s argument.
In this case, `Performance/HashEachMethods` adds a falsy offense.
Cause
=====
The cop handles only argument names to detect unused. So the cop does not work properly if an unused argument that has same name exists in other block.
Solution
=====
Check declared location of arguments instead of argument name.
Note
====
I found another bug while I was fixing this bug.
Auto-correction of this cop does not work properly.
For example:
```ruby
# Auto-correct the following code.
foo.each { |key, _v| p key }
# Expected
foo.each_key { |key| p key }
# Actual
foo.each_value { |key| p key }
```
This change will fix the bug also.
pocke
commented
Oct 19, 2017
| corrector.replace(node.loc.expression, new_source) | ||
| end | ||
|
|
||
| def correct_plain_each(node, corrector) | ||
| method = @args.include?(:k) ? :key : :value |
There was a problem hiding this comment.
This :k is a cause of the auto-correction bug.
|
👍 |
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Problem
Performance/HashEachMethodshas a false positive for the following code.The
eachdoes not have any unused arguments.keyandvalueare used. So, this cop should not add an offense for the code.But the cop adds an offence for the code currently.
This cause is the
sumhas an unused argument, and the argument is namedkey, the name is same as theeach's argument.In this case,
Performance/HashEachMethodsadds a falsy offense.Cause
The cop handles only argument names to detect unused. So the cop does not work properly if an unused argument that has same name exists in other block.
Solution
Check declared location of arguments instead of argument name.
Note
I found another bug while I was fixing this bug.
Auto-correction of this cop does not work properly.
For example:
This change will fix the bug also.
Before submitting the PR make sure the following are checked:
[Fix #issue-number](if the related issue exists).master(if not - rebase it).rake spec) are passing.rake internal_investigation.and description in grammatically correct, complete sentences.
rake generate_cops_documentation(required only when you've added a new cop or changed the configuration/documentation of an existing cop).