6ca7dd2cc6
* Add rust to rule S2208 * Update RSPEC --------- Co-authored-by: yassin-kammoun-sonarsource <yassin-kammoun-sonarsource@users.noreply.github.com> Co-authored-by: yassin-kammoun-sonarsource <yassin.kammoun@sonarsource.com>
63 lines
1.8 KiB
Plaintext
63 lines
1.8 KiB
Plaintext
== Why is this an issue?
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Importing every public name from a module using a wildcard (``++use _::*++``) is a bad idea because:
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* It could lead to conflicts between names defined locally and the ones imported.
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* It reduces code readability as developers will have a hard time knowing where names come from.
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* It clutters the local namespace, which makes debugging more difficult.
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Remember that imported names can change when you update your dependencies. A wildcard import that works today might be broken tomorrow.
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=== Exceptions
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No issue will be raised for modules that their name contains ``++prelude ++``. Many crates, including the standard library, provide modules named ``++prelude ++`` that are specifically designed for wildcard import.
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No issue will be raised in test modules. This is defined as any module with ``++test++`` in the name.
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== How to fix it
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There are two ways to avoid a wildcard import:
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* Replace it with `use mymodule;` and access module members as `mymodule::myfunction`. If the module name is too long, alias it to a shorter name. Example: `use std::collections as col;`
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* List every imported name. If necessary, import statements can be split on multiple lines using parentheses (preferred solution) or backslashes.
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=== Code examples
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==== Noncompliant code example
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[source,rust]
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----
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use std::collections::*; // Noncompliant
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fn main() {
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let mut map = HashMap::new();
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map.insert(1, 2);
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}
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----
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==== Compliant solution
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[source,rust]
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----
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use std::collections::HashMap;
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fn main() {
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let mut map = HashMap::new();
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map.insert(1, 2);
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}
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----
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Or
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[source,rust]
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----
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use std::collections::HashMap as HM;
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fn main() {
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let mut map = HM::new();
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map.insert(1, 2);
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}
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----
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== Resources
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=== Documentation
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* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_imports
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