Kotlin Coding Practices

Kotlin Coding Practices

Application skill for Kotlin style learning (from the archived awesome-guidelines style capsules). For Android/Compose/KMP stack patterns, load stack capsules in skills/*-foundation.

Core Principle

Kotlin readability is official formatter mechanics plus immutability-first idioms, explicit imports, semantic class layout, stable library surfaces.

When to Use / NOT

• Kotlin JVM/KMP/application/library source, ktlint/detekt CI.
• Reviewing naming, formatting, class organization, public API.

NOT when:

• Non-Kotlin code.
• Generated code, validate generators, not hand-edits.
• Compose/Android-only rules, use Android style guide / foundation when stack is Android.

Workflow

1. Format & layout, 4-space, braces, modifiers, trailing commas (kotlin-style-formatting-layout.md).
2. Naming & files, packages, files, constants, backing props (kotlin-style-naming-files.md).
3. Organization, directories, class layout, overloads (kotlin-style-organization-classes.md).
4. Idioms & API, val, defaults, expression control flow, library KDoc (kotlin-style-idioms-api.md).
5. Verify, ktlint/detekt + ./gradlew check (or project equivalent) on changed modules.

Red Flags

• Wildcard imports
• Tabs or inconsistent indent
• var when never reassigned
• Mutable collection types in public API parameters
• Overloads instead of default parameters
• Util.kt / meaningless file names
• Binary when instead of if
• Public API without return types (libraries)

Verification

• ktlint/detekt on changed files
• Compile + tests for touched modules
• Capsule checklist on public API review

References

• awesome-guidelines/references/kotlin-style-learning-note.md
• awesome-guidelines/references/kotlin-style-formatting-layout.md
• awesome-guidelines/references/kotlin-style-naming-files.md
• awesome-guidelines/references/kotlin-style-organization-classes.md
• awesome-guidelines/references/kotlin-style-idioms-api.md