Code quality is one of the most important aspects of programming world. As it impacts our overall software quality i.e., how safe, secure, and reliable our codebase is.
Code quality is not only to perform efficiently but also to make code more readable.
Essentially, code that is considered good:
A code should be:
- readable,
- follows consistent style,
- testable,
- well documented,
- follows Single Responsibility Approach
To achieve this we have some tools in Rust Programming:
- Clippy: A tool to improve code quality of the Rust Project.
- Rustfmt: A tool for formatting Rust code according to style guidelines.
Clippy
It is a code completion tool for helping developers of a library or application to write better code. Clippy uses lints to improve code quality.
Lint is a program that supports checking the source code for Programmatic and Stylistic errors, which makes it more helpful for identifying some common or uncommon mistakes during code development process.
Lint majorly focuses on:
- preventing discrepancy
- coherence to coding standards
- provides logical errors in your program
Some lint groups are already enabled by default:
- clippy::style
- clippy::correctness
- clippy::complexity
- clippy::perf
clippy::style
Used for code that should be written in a more idiomatic way.
clippy::correctness
Helps to detect hard error code.
clippy::complexity
Prevents to write complex code.
clippy::perf
Provides ability to write code in a faster way.
Lints that can be configured in Rust Stable
- blacklisted-name
- too-many-arguments
- enum-variant-names
- single-char-binding-names-threshold
- cognitive-complexity-threshold
- max-fn-params-bools
- max-struct-bools
- too-many-lines-threshold
blacklisted_name:
Contains a list of names that are blacklisted to use in a program.
Input Type: Vec<String>
Default value: ["foo", "bar", "baz", "quux"]
Category: Style
Example: blacklisted-names = [“blacklist_name1”, “blacklist_name2”]too_many_arguments:
Sets the threshold of number of arguments for a function.
Input Type: u64
Default value: 7
Category: Complexity
Example: too-many-arguments-threshold = 7enum_variant_names:
Denotes the minimum number of variants for an enum.
Input Type: u64
Default value: 3
Category: Style
Example: enum-variant-name-threshold = 3many_single_char_names:
Sets the minimum number of single characters used in a program.
Input Type: u64
Default value: 4
Category: Style
Example: single-char-binding-names-threshold = 2cognitive_complexity:
Check for methods containing high cognitive complexity.
Input Type: u64
Default value: 25
Category: Nursery
Example: cognitive-complexity-threshold = 20fn_params_excessive_bools:
Represents maximum number of bools function parameters can have.
Input Type: u64
Default value: 3
Category: Pedantic
Example: max-fn-params-bools = 2struct_excessive_bools:
Denotes maximum number of bools a struct can have.
Input Type: u64
Default value: 3
Category: Pedantic
Example: max-struct-bools = 2too_many_lines:
Validates maximum number of lines a function can have.
Input Type: u64
Default value: 3
Category: Pedantic
Example: too-many-lines-threshold = 2Attributes to allow/deny/warn Clippy lints in your codebase:
Allow#[allow(clippy::lint_group)]
or,
Deny#[deny(clippy::lint_group)]
or else,
Warn#[warn(clippy::lint_group)]All the properties must be stored in the clippy.toml file.
Example:
blacklisted-names = ["foo", "too"]
too-many-arguments-threshold = 3
enum-variant-name-threshold = 3
single-char-binding-names-threshold = 0
cognitive-complexity-threshold = 20
max-fn-params-bools = 3
max-struct-bools = 3
too-many-lines-threshold = 30Note: Instead of using attributes in codebase it’s recommended to pass arguments as a command line with `cargo clippy`
Examples:
cargo clippy — -W clippy::pedantic // warns about pedantic
or,
cargo clippy — -A clippy::pedantic // allows pedantic
or,
cargo clippy — -D clippy::pedantic // denies pedantic
Rustfmt
Rustfmt is a tool specifically designed for code indentation and code formatting. It is used to make code more readable and makes code more comprehensive.
Code formatting is a mechanical task that takes both time and effort. By using customized formatting tool, a programmer is relieved of this task and can concentrate on more important things.
Custom configuration of Rustfmt for Rust Stable:
- max_width
- tab_spaces
- merge_derives
- reorder_imports
- fn_args_layout
- hard_tabs
- reorder_modules
- use_field_init_shorthand
max_width:
Represents maximum width of each line.
Default value: 100
Input type: unsigned integer
Example: max_width = 80 // sets 80 chars as a maximum widthtab_spaces:
Denotes number of tabs.
Default value: 4
Input type: unsigned integer
Example: tab_spaces = 4 // sets 4 tab spaces as a maximumreorder_imports:
Responsible for reordering imports in a lexicographical order.
Default value: true
Input type: boolean
Example: reorder_imports = false // denies for reorder imports merge_derives:
Merge multiple derives into a single one.
Default value: true
Input type: boolean
Example: merge_derives = false // disables for merge derivefn_args_layout:
Represents the layout of parameters in a function signature.
Default value: “Tall”
Input type: "Compressed", “Tall”, “Vertical”
Example: merge_derives = “Compressed” // allows layout of parameters in compressed formhard_tabs:
Responsible for allowing/denying of tab spaces.
Default value: false
Input type: boolean
Example: hard_tabs = true // allows to set tab spacesreorder_modules:
Helps to reorder modules in a lexicographical manner.
Default value: true
Input type: boolean
Example: reorder_modules = false // disables the ordering of modulesuse_field_init_shorthand:
Allow us to use field initialization in a compact way.
Default value: false
Input type: boolean
Example: use_field_init_shorthand = true // allows field initializationAll the properties must be stored in the rustfmt.toml file.
Example:
max_width = 80
tab_spaces = 4
merge_derives = true
reorder_imports = false
fn_args_layout = "Compressed"
hard_tabs = false
reorder_modules = true
use_field_init_shorthand = trueThank you for reading!!!
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