https://github.com/hbmartin/hbmartin-detekt-rules
A somewhat opinionated ruleset for Detekt, primarily intended to avoid crashes and bugs related to mutability.
https://github.com/hbmartin/hbmartin-detekt-rules
detekt detekt-rules immutability kotlin psi static-analysis
Last synced: 5 months ago
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A somewhat opinionated ruleset for Detekt, primarily intended to avoid crashes and bugs related to mutability.
- Host: GitHub
- URL: https://github.com/hbmartin/hbmartin-detekt-rules
- Owner: hbmartin
- License: apache-2.0
- Created: 2023-07-26T22:56:45.000Z (about 2 years ago)
- Default Branch: main
- Last Pushed: 2025-01-27T09:30:54.000Z (9 months ago)
- Last Synced: 2025-04-01T03:30:23.038Z (7 months ago)
- Topics: detekt, detekt-rules, immutability, kotlin, psi, static-analysis
- Language: Kotlin
- Homepage: https://central.sonatype.com/artifact/me.haroldmartin/hbmartin-detekt-rules
- Size: 444 KB
- Stars: 5
- Watchers: 1
- Forks: 0
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Hbmartin's detekt rules
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[](https://github.com/hbmartin/hbmartin-detekt-rules/actions/workflows/pre-merge.yml)
[](https://codecov.io/github/hbmartin/hbmartin-detekt-rules)
[](https://www.codefactor.io/repository/github/hbmartin/hbmartin-detekt-rules)
[](https://sonarcloud.io/dashboard?id=hbmartin_intellij-build-webhook-notifier)
[](https://central.sonatype.com/artifact/me.haroldmartin/hbmartin-detekt-rules)
These are my opinions. There are many like them but these are mine. 😄
## Quick Start
Inside of your `dependencies` block add the following: (for more details see [adding more rule sets](https://github.com/detekt/detekt#adding-more-rule-sets))
```kotlin
detektPlugins("me.haroldmartin:hbmartin-detekt-rules:0.1.7")
```
Then add to your detekt configuration as in the section below to activate rules. Note that the AvoidFirstOrLastOnList and AvoidMutableCollections rules require [type resolution](https://detekt.dev/docs/gettingstarted/type-resolution) to be active.
## Type Resolution
Some of these rules require type resolution, which typically happens when running `detect*Main` task. For more details (including instructions for multiplatform) see [Using Type Resolution](https://detekt.dev/docs/gettingstarted/type-resolution/) in the detekt docs.
If you rely on the `check` task to run detekt, you can replace the default detekt chek with a typed check using a configuration like:
```kotlin
tasks.named("check").configure {
this.setDependsOn(
this.dependsOn.filterNot {
it is TaskProvider<*> && it.name == "detekt"
} + tasks.named("detektMain"),
)
}
```
## Configuration
Add below to your `detekt.yml` and modify to suit your needs. Only the `AvoidVarsExceptWithDelegate` rule has additional configuration options, where you may provide a regex to allow additional variable delegates.
```yaml
HbmartinRuleSet:
AvoidFirstOrLastOnList:
active: true
AvoidMutableCollections:
active: true
AvoidVarsExceptWithDelegate:
active: true
allowedDelegates:
- 'remember\w*'
- 'mutableState\w*'
DontForceCast:
active: true
MutableTypeShouldBePrivate:
active: true
NoCallbacksInFunctions:
active: true
ignoreAnnotated: ['Composable']
allowExtensions: true
allowReceivers: true
allowInline: false
NoNotNullOperator:
active: true
NoVarsInConstructor:
active: true
WhenBranchSingleLineOrBraces:
active: true
```
## Rules
### AvoidFirstOrLastOnList
Finds uses of `.first()` or `.list()` on a list type. These are dangerous calls since they will throw a `NoSuchElementException ` exception if the list is empty. Prefer to use .firstOrNull() or .lastOrNull() instead. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/AvoidFirstOrLastOnListTest.kt) for triggering and non-triggering examples.
### AvoidMutableCollections
Finds uses of mutable collections e.g. `MutableList<>`. These are highly likely to lead to bugs, prefer to use functional patterns to create new lists modified as needed. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/AvoidMutableCollectionsTest.kt) for triggering and non-triggering examples.
### AvoidVarsExceptWithDelegate
Finds uses of mutable `var` fields. These are highly likely to lead to bugs, prefer to use a `Flow` or some reactive type for any mutable state. There is an exception made for `var`s which are implemented with the [delegation pattern](https://kotlinlang.org/docs/delegation.html), which is particularly common when using Compose. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/AvoidVarsExceptWithDelegateTest.kt) for triggering and non-triggering examples.
### DontForceCast
Finds uses of `as` to force cast. These are likely to lead to crashes, especially in unforeseen circumstances, prefer to safely cast with `as?` instead. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/DontForceCastTest.kt) for triggering and non-triggering examples.
### MutableTypeShouldBePrivate
Finds publicly exposed mutable types e.g. `MutableStateFlow<>`. These are likely to lead to bugs, prefer to expose a non-mutable `Flow` (e.g. with `_mutableStateFlow.asStateFlow()`) or other non-mutable type. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/MutableTypeShouldBePrivateTest.kt) for triggering and non-triggering examples.
### NoCallbacksInFunctions
Finds uses of callbacks in functions. This can lead to a mixed concurrency paradigm and are likely to lead to bugs or stalled threads, prefer to use a suspend function instead. Use the `ignoreAnnotated` configuration to allow callbacks in `@Composable` functions. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/NoCallbacksInFunctionsTest.kt) for triggering and non-triggering examples.
### NoNotNullOperator
Finds uses of `!!` to force unwrap. These are likely to lead to crashes, prefer to safely unwrap with `?.` or `?:` instead. Otherwise the Kotlin docs will make fun of you for being an [NPE lover](https://kotlinlang.org/docs/null-safety.html#the-operator). [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/NoNotNullOperatorTest.kt) for triggering and non-triggering examples.
### NoVarsInConstructor
Finds uses of `var` in a constructor. These are likely to lead to bugs, always use `val` instead. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/NoVarsInConstructorTest.kt) for triggering and non-triggering examples.
### WhenBranchSingleLineOrBraces
A stylistic rule that require that either a when expression be on a single line or use braces. Either case should have a single space after the arrow. [See here](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/src/test/kotlin/me/haroldmartin/detektrules/WhenBranchSingleLineOrBracesTest.kt) for triggering and non-triggering examples.
## Contributing
* Jump in and modify this project! Start by cloning it with `git clone git@github.com:hbmartin/hbmartin-detekt-rules.git`, then open it in IntelliJ and run the tests.
* Read the [detekt documentation](https://detekt.dev/docs/introduction/extensions/) to learn more about how to write rules.
* [PRs](https://github.com/hbmartin/hbmartin-detekt-rules/pulls) and [bug reports / feature requests](https://github.com/hbmartin/hbmartin-detekt-rules/issues) are all welcome!
* Checked with detekt, including the ruleauthors set and, of course, [running these rules on itself](https://github.com/hbmartin/hbmartin-detekt-rules/blob/main/build.gradle.kts#L20) 😏
* Treat other people with helpfulness, gratitude, and consideration! See the [JetBrains CoC](https://confluence.jetbrains.com/display/ALL/JetBrains+Open+Source+and+Community+Code+of+Conduct)
## Authors
* [Harold Martin](https://www.linkedin.com/in/harold-martin-98526971/) - harold.martin at gmail
* Significant inspiration from [kure-potlin by neeffect](https://github.com/neeffect/kure-potlin) and [Doist detekt-rules](https://github.com/Doist/detekt-rules)