foxhunt/rustfmt.toml

# Rustfmt Configuration for Foxhunt HFT System
# IMPORT STANDARDIZATION AND TYPE GOVERNANCE SUPPORT

# =============================================================================
# 🎯 IMPORT ORGANIZATION - CRITICAL FOR TYPE GOVERNANCE
# =============================================================================

# Group imports to enforce canonical type usage patterns
imports_granularity = "Module"         # Group by module for clarity
group_imports = "StdExternalCrate"     # Separate std, external, and local
imports_layout = "Vertical"            # Vertical layout for readability

# =============================================================================
# 📋 STANDARD IMPORT ORDER FOR ALL CRATES
# =============================================================================
# 
# This order enforces the type governance hierarchy:
# 1. Standard library (std::)
# 2. External crates (serde, tokio, etc.)  
# 3. Prelude import (trading_engine::types::prelude::*)
# 4. Configuration imports (config::*)
# 5. Local crate imports
# 6. Generated code imports (proto, etc.)

# =============================================================================
# 🔒 TYPE GOVERNANCE FORMATTING RULES
# =============================================================================

# Force prelude imports to be clearly visible
reorder_imports = true              # Automatic import reordering
reorder_modules = true              # Module order consistency
merge_imports = false               # Keep imports separate for clarity

# Ensure wildcard imports (required for prelude) are formatted consistently
use_small_heuristics = "Max"       # Better formatting decisions

# =============================================================================
# 📏 LINE LENGTH AND WRAPPING
# =============================================================================

max_width = 100                     # Consistent with HFT code standards
hard_tabs = false                   # Use spaces for consistency
tab_spaces = 4                      # 4-space indentation

# Import-specific line handling
use_try_shorthand = true            # Use ? operator
imports_indent = "Block"            # Indent wrapped imports
merge_derives = true                # Combine #[derive(...)] attributes

# =============================================================================
# 🧹 CODE STRUCTURE FOR MAINTAINABILITY
# =============================================================================

# Function and type formatting that supports type governance
fn_args_layout = "Tall"             # Vertical function arguments
brace_style = "SameLineWhere"       # Consistent brace placement
where_single_line = true            # Compact where clauses when possible

# Struct and enum formatting (important for canonical types)
struct_field_align_threshold = 20   # Align fields in structs
enum_discrim_align_threshold = 20   # Align enum discriminants
use_field_init_shorthand = true     # Use shorthand field initialization

# =============================================================================
# 📝 DOCUMENTATION AND COMMENTS
# =============================================================================

# Ensure type governance documentation is preserved
format_code_in_doc_comments = true  # Format code examples
wrap_comments = true                 # Wrap long comments
comment_width = 80                  # Comment line length
normalize_comments = true            # Consistent comment formatting
normalize_doc_attributes = true      # Consistent doc attributes

# =============================================================================
# ⚡ HFT-SPECIFIC FORMATTING
# =============================================================================

# Performance-critical code formatting
single_line_if_else_max_width = 50  # Compact conditionals
force_multiline_blocks = false      # Allow compact blocks
overflow_delimited_expr = true      # Handle long expressions

# Match expression formatting (common in trading logic)
match_block_trailing_comma = true   # Consistent comma usage
match_arm_blocks = false            # Compact match arms where possible
newline_style = "Unix"              # Consistent line endings

# =============================================================================
# 🎨 VISUAL ORGANIZATION
# =============================================================================

# Make type governance violations more visible through formatting
blank_lines_lower_bound = 0         # Minimum blank lines
blank_lines_upper_bound = 2         # Maximum blank lines
empty_item_single_line = false      # No empty items on single line

# Indent and alignment for complex types
array_width = 60                    # Array formatting threshold
attr_fn_like_width = 70             # Attribute formatting
chain_width = 60                    # Method chain formatting
fn_call_width = 60                  # Function call formatting
struct_lit_width = 18               # Struct literal formatting
struct_variant_width = 35           # Enum struct variant formatting

# =============================================================================
# 🔧 MACRO AND SPECIAL SYNTAX
# =============================================================================

# Handle Rust macros (common in HFT for performance)
format_macro_matchers = true        # Format macro matchers
format_macro_bodies = true          # Format macro bodies
macro_use_wildcards = false         # Explicit macro imports

# Generated code formatting (protobuf, etc.)
format_generated_files = false      # Don't format generated files
skip_children = false               # Format all Rust files

# =============================================================================
# 🚨 TYPE GOVERNANCE INTEGRATION
# =============================================================================

# These settings specifically support type governance:

# 1. Import grouping makes prelude imports clearly visible
# 2. Consistent formatting helps identify duplicate type definitions
# 3. Documentation formatting preserves governance comments
# 4. Line length and structure support code review for violations

# =============================================================================
# 🎯 VALIDATION AND ENFORCEMENT
# =============================================================================

# Integration with type governance validation:
# - CI runs `cargo fmt --check` to ensure consistent formatting
# - Consistent imports make duplicate detection easier
# - Clear structure supports code review for governance violations

# =============================================================================
# 🏗️ EXAMPLES OF ENFORCED PATTERNS
# =============================================================================
#
# Standard service import pattern:
# ```rust
# use std::collections::HashMap;
# use std::time::Duration;
#
# use serde::{Deserialize, Serialize};
# use tokio::sync::RwLock;
#
# use trading_engine::types::prelude::*;  // CANONICAL TYPES
# use config::*;                          // CONFIGURATION ONLY
#
# use crate::repository::OrderRepository;
# use crate::service::OrderService;
# ```
#
# Test import pattern:
# ```rust  
# use std::time::SystemTime;
#
# use trading_engine::types::prelude::*;  // CANONICAL TYPES ONLY
#
# use crate::test_utils::*;
# ```