Function derive_base_name

src/code_actions/extract_function.rs:410–481

Pick a base name from the naming context (before deduplication).

(ctx: &NamingContext)

/// Pick a base name from the naming context (before deduplication).
fn derive_base_name(ctx: &NamingContext) -> String {
    let enc = ctx.enclosing_name;

    // 1. Guard strategies → {enclosing}Guard
    match ctx.return_strategy {
        ReturnStrategy::VoidGuards
        | ReturnStrategy::UniformGuards(_)
        | ReturnStrategy::NullGuardWithValue(_) => {
            if !enc.is_empty() {
                return format!("{}Guard", enc);
            }
            return "guard".to_string();
        }

        // 2. SentinelNull → try{Enclosing}
        ReturnStrategy::SentinelNull => {
            if !enc.is_empty() {
                return format!("try{}", capitalise(enc));
            }
            return "tryExtract".to_string();
        }

        // 3–4. TrailingReturn
        ReturnStrategy::TrailingReturn => {
            // 3. Factory: body contains `new ClassName` → create{ClassName}
            if let Some(class_name) = detect_factory_pattern(ctx.body_text) {
                return format!("create{}", class_name);
            }
            // 4. Generic trailing return
            if !enc.is_empty() {
                // If there's a return type, use it for a more descriptive name
                if !ctx.trailing_return_type.is_empty() {
                    // Only use the return type if it's a class name (starts uppercase)
                    if let Some(name) = ctx.trailing_return_type.base_name() {
                        return format!("get{}", name);
                    }
                }
                return format!("get{}Result", capitalise(enc));
            }
        }

        ReturnStrategy::None | ReturnStrategy::Unsafe => {}
    }

    // 5. Pure output → render{Enclosing}
    if is_pure_output(ctx.body_text) && !enc.is_empty() {
        return format!("render{}", capitalise(enc));
    }

    // 6. Single return variable → compute{VarName}
    if ctx.return_var_names.len() == 1 {
        let var = ctx.return_var_names[0].trim_start_matches('$');
        if !var.is_empty() {
            return format!("compute{}", capitalise(var));
        }
    }

    // 7. Ends with output (setup + echo/print) → render{Enclosing}