rustfmt.toml

# Rustfmt configuration for systemprompt.io code formatting standards
# Requires nightly Rust (configured via rust-toolchain.toml)
# See: tests/validator/coding-standards.md

# ============================================================================
# EDITION
# ============================================================================
edition = "2024"

# ============================================================================
# LINE WIDTH AND INDENTATION
# ============================================================================

# Maximum line width - balances readability with horizontal space
max_width = 100

# Use spaces, not tabs (consistency across editors)
hard_tabs = false
tab_spaces = 4

# ============================================================================
# IMPORT ORGANIZATION
# ============================================================================

# Automatically reorder imports (std -> external -> workspace -> local)
reorder_imports = true

# Group imports by module
# Example:
#   use std::collections::HashMap;
#   use std::sync::Arc;
#
#   use anyhow::Result;
#   use tokio::sync::RwLock;
imports_granularity = "Module"

# ============================================================================
# FUNCTION AND TYPE FORMATTING
# ============================================================================

# Force explicit ABI on extern functions for clarity
force_explicit_abi = true

# Remove unnecessary nested parentheses
remove_nested_parens = true

# Control heuristics for formatting small items
use_small_heuristics = "Default"

# Prefer explicit Ok/Err over try! macro (try! is deprecated)
use_try_shorthand = false

# Prefer explicit field initialization over shorthand
# Example: Agent { id: id } instead of Agent { id }
# Rationale: Explicit is clearer, matches our "no abbreviations" rule
use_field_init_shorthand = false

# ============================================================================
# WHITESPACE AND NEWLINES
# ============================================================================

# Unix line endings (LF not CRLF)
newline_style = "Unix"

# Blank lines - preserve structure
blank_lines_upper_bound = 2
blank_lines_lower_bound = 0

# ============================================================================
# COMMENTS
# ============================================================================

# Normalize comment formatting
normalize_comments = true

# Wrap comments at max_width
wrap_comments = true

# Format code in doc comments (``` blocks)
format_code_in_doc_comments = true

# ============================================================================
# MATCH AND CONTROL FLOW
# ============================================================================

# Control flow brace style
brace_style = "SameLineWhere"

# Match block formatting - prefer block style
match_block_trailing_comma = true

# ============================================================================
# MISCELLANEOUS
# ============================================================================

# Do NOT enable `format_strings`: the unstable splitter mangles long string
# literals containing escaped quotes (e.g. JSON test fixtures), terminating
# them early and producing syntax errors on every `cargo fmt` run.
format_strings = false

# Merge derives into single line when possible
merge_derives = true