Prompt file imported from adzkar/badminton-tournament-api (.windsurf/workflows/handle-warnings.md). Copyright stays with the author.

Workflow: Handle Rust Warnings

This workflow guides you through identifying, analyzing, and fixing Rust compiler warnings.

Step 0 — Identify Warnings

Run cargo check to see all current warnings:

cargo check

Common warning types:

• unused_imports - Imports that are not used
• dead_code - Functions, structs, or fields that are never used
• unused_variables - Variables that are declared but not read

Step 1 — Analyze Each Warning

For each warning, determine the appropriate action:

1a. Remove the code

Remove when:

• The code is truly unused and serves no purpose
• It's a leftover from refactoring
• It's a duplicate of something else

Examples:

• Unused imports in prelude files
• Error variants that are never constructed
• Dead functions that were replaced

1b. Add #[allow(dead_code)] with TODO

Add allow when:

• The code is part of a public API or structure
• The code is used in a different layer (e.g., domain model field used in infrastructure)
• The code is generated and should not be modified
• The code will be used in the future (with a clear TODO explaining why)

Always add a TODO comment explaining:

• Why the code exists
• Where/how it's used
• When it might be used in the future

Example:

// TODO: Field is used in infrastructure layer mapping (sea_tournament_repository.rs) but not directly in domain model
#[allow(dead_code)]
pub deleted_at: Option<DateTime<Utc>>,

Step 2 — Search for Usage

Before removing code, verify it's truly unused:

# Search for the identifier across the codebase
grep -r "IdentifierName" src/

For prelude re-exports, check if anything imports from the prelude:

grep -r "use.*prelude" src/

For error variants, check if they're ever constructed:

grep -r "AppError::VariantName" src/

Step 3 — Apply Fixes

Removing unused imports

Simply delete the import line.

Removing unused error variants

Remove both:

1. The variant definition in the enum
2. The HTTP status mapping in the IntoResponse implementation

Adding allow attributes

Add the attribute above the item with a TODO comment.

Step 4 — Verify

After making changes:

cargo check

Ensure:

• No warnings remain
• Code compiles successfully
• No new errors were introduced

Common Patterns in This Project

Prelude Pattern

• Issue: Entity re-exports in src/infrastructure/database/entities/prelude.rs may be unused
• Fix: Remove if code uses direct imports instead of prelude
• Check: Search for use.*prelude to see if prelude is used

Domain Model Fields

• Issue: Fields like deleted_at in domain models trigger dead_code warnings
• Fix: Add #[allow(dead_code)] with TODO explaining infrastructure layer usage
• Reason: Domain models are mapped to/from SeaORM entities in infrastructure layer

Error Variants

• Issue: Error variants defined but never constructed
• Fix: Remove both the variant and its HTTP mapping
• Check: Search for AppError::VariantName usage

Constraints

• Never suppress warnings without understanding why they exist
• Always add TODO comments when using #[allow(...)]
• Prefer removal over suppression when code is truly unused
• Verify usage with grep before removing anything
• Run cargo check after every change to verify the fix