linter_rules.yaml

# =============================================================================
# Embedded AI Linter Rules
# Based on JSF AV C++ Coding Standards (Doc. No. 2RDU00001 Rev C)
# Simplified for embedded AI / edge deployment contexts
#
# Each rule has:
#   enabled:    true/false to toggle the rule
#   severity:   "error" | "warning" | "info"
#   jsf_ref:    original JSF AV Rule number(s) for traceability
#   params:     rule-specific thresholds or configuration
# =============================================================================

meta:
  name: "Embedded AI Linter"
  version: "1.0.0"
  description: >
    Simplified JSF AV rules adapted for safety-aware embedded C++ code
    used in the Embedded AI book projects.
  file_extensions: [".cpp", ".h", ".hpp", ".c"]

# ---------------------------------------------------------------------------
# Category 1: Code Size and Complexity
# ---------------------------------------------------------------------------
complexity:

  max_function_length:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 1"
    params:
      max_lines: 100  # JSF allows 200; tightened for book examples
    description: "Function bodies shall not exceed the configured line limit."

  max_function_args:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 110"
    params:
      max_args: 6  # JSF allows 7
    description: "Functions shall not have more than the configured number of parameters."

  max_line_length:
    enabled: true
    severity: info
    jsf_ref: "AV Rule 41"
    params:
      max_chars: 100  # JSF allows 120; tightened for book formatting
    description: "Source lines shall not exceed the configured character limit."

# ---------------------------------------------------------------------------
# Category 2: Prohibited Language Features
# ---------------------------------------------------------------------------
prohibited_features:

  no_goto:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 189"
    pattern: "\\bgoto\\b"
    description: "The goto statement shall not be used."

  no_continue:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 190"
    pattern: "\\bcontinue\\b"
    description: "The continue statement shall not be used."

  no_exceptions:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 208"
    patterns:
      - "\\bthrow\\b"
      - "\\bcatch\\b"
      - "\\btry\\b"
    description: "C++ exceptions (throw, catch, try) shall not be used."

  no_unions:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 153"
    pattern: "\\bunion\\b"
    description: "Unions shall not be used."

  no_comma_operator:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 168"
    description: "The comma operator shall not be used (excluding for-loop init and function args)."

  no_errno:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 17"
    pattern: "\\berrno\\b"
    description: "The error indicator errno shall not be used."

  no_setjmp_longjmp:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 20"
    patterns:
      - "\\bsetjmp\\b"
      - "\\blongjmp\\b"
    description: "setjmp and longjmp shall not be used."

  no_signal_h:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 21"
    pattern: "<signal\\.h>|<csignal>"
    description: "The signal handling facilities shall not be used."

  no_stdio:
    enabled: false  # Disabled: book examples use printf for demonstration
    severity: warning
    jsf_ref: "AV Rule 22"
    pattern: "<stdio\\.h>|<cstdio>"
    description: "The I/O library stdio.h shall not be used."

  no_atoi_atof:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 23"
    patterns:
      - "\\batof\\b"
      - "\\batoi\\b"
      - "\\batol\\b"
    description: "atof, atoi, and atol shall not be used."

  no_abort_exit:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 24"
    patterns:
      - "\\babort\\s*\\("
      - "(?<!_)exit\\s*\\("
      - "\\bgetenv\\s*\\("
      - "\\bsystem\\s*\\("
    description: "abort, exit, getenv, and system shall not be used."

  no_recursion:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 119"
    description: "Functions shall not call themselves directly or indirectly."

  no_register:
    enabled: true
    severity: info
    jsf_ref: "AV Rule 140"
    pattern: "\\bregister\\b"
    description: "The register storage class specifier shall not be used."

  no_pointer_arithmetic:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 215"
    description: "Pointer arithmetic should be avoided. Use array indexing or iterators."

# ---------------------------------------------------------------------------
# Category 3: Type Safety
# ---------------------------------------------------------------------------
type_safety:

  no_raw_int_types:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 209"
    patterns:
      - "(?<!\\w)\\bint\\b(?!\\w|_t|8|16|32|64)"
      - "(?<!\\w)\\bshort\\b(?!\\w)"
      - "(?<!\\w)\\blong\\b(?!\\w)"
    description: >
      Basic types int, short, long shall not be used directly.
      Use fixed-width types: int8_t, int16_t, int32_t, uint8_t, etc.

  no_c_style_casts:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 185"
    description: >
      C++ style casts (static_cast, reinterpret_cast, const_cast) shall be
      used instead of C-style casts.

  no_implicit_narrowing:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 180"
    description: "Implicit conversions that may lose information shall not be used."

  no_octal_constants:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 149"
    pattern: "(?<!\\.)\\b0[0-7]+\\b"
    description: "Octal constants (other than zero) shall not be used."

  hex_uppercase:
    enabled: true
    severity: info
    jsf_ref: "AV Rule 150"
    pattern: "0x[0-9a-fA-F]*[a-f][0-9a-fA-F]*"
    description: "Hexadecimal constants shall use uppercase letters."

  literal_suffix_uppercase:
    enabled: true
    severity: info
    jsf_ref: "AV Rule 14"
    pattern: "\\d+[uUlLfF]*[ul]"
    description: "Literal suffixes shall use uppercase letters (e.g. 1U, 2.0F, 3L)."

# ---------------------------------------------------------------------------
# Category 4: Memory and Resource Safety
# ---------------------------------------------------------------------------
memory_safety:

  no_dynamic_alloc_after_init:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 206"
    description: >
      Allocation/deallocation from the free store (heap) shall not occur
      after initialization. Use static allocation or memory pools.

  no_malloc_free:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 206"
    patterns:
      - "\\bmalloc\\s*\\("
      - "\\bfree\\s*\\("
      - "\\bcalloc\\s*\\("
      - "\\brealloc\\s*\\("
    description: "C-style memory allocation (malloc/free/calloc/realloc) shall not be used."

  no_raw_new_delete:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 206"
    patterns:
      - "(?<!operator)\\bnew\\b"
      - "(?<!operator)\\bdelete\\b"
    description: >
      Raw new/delete should be avoided outside initialization.
      Prefer RAII, containers, or static allocation.

  volatile_only_for_hardware:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 205"
    pattern: "\\bvolatile\\b"
    description: >
      The volatile keyword shall only be used when directly interfacing
      with hardware registers. Flag for manual review.

# ---------------------------------------------------------------------------
# Category 5: Control Flow
# ---------------------------------------------------------------------------
control_flow:

  braces_required:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 59"
    description: >
      The body of if, else if, else, while, do-while, and for statements
      shall always be enclosed in braces.

  switch_default_required:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 194"
    description: "All switch statements shall contain a default case."

  switch_break_required:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 193"
    description: "Every non-empty case in a switch shall be terminated with break."

  no_float_loop_counter:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 197"
    pattern: "for\\s*\\([^)]*(?:float|double)[^)]*;"
    description: "Floating-point variables shall not be used as loop counters."

  no_float_exact_compare:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 202"
    description: "Floating-point values shall not be tested for exact equality."

  single_return:
    enabled: false  # Disabled: modern embedded style permits early returns
    severity: info
    jsf_ref: "AV Rule 113"
    description: "Functions should have a single exit point."

# ---------------------------------------------------------------------------
# Category 6: Style and Naming
# ---------------------------------------------------------------------------
style:

  no_tabs:
    enabled: true
    severity: info
    jsf_ref: "AV Rule 43"
    description: "Tab characters should not be used for indentation."

  no_magic_numbers:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 151"
    description: >
      Numeric literals (other than 0 and 1) shall not appear in code.
      Use named constants or constexpr.
    params:
      allowed_values: [0, 1, 2, -1]

  one_declaration_per_line:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 152"
    description: "Multiple variable declarations shall not appear on the same line."

  no_commented_out_code:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 127"
    description: "Commented-out code shall be deleted."

  no_identifier_leading_underscore:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 47"
    pattern: "(?:int|float|double|char|bool|auto|void|const|static|unsigned|signed|uint\\d+_t|int\\d+_t|size_t)\\s+_\\w+"
    description: "Identifiers shall not begin with an underscore."

  include_guard_required:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 27, 35"
    description: "Header files shall use #ifndef/#define/#endif include guards."

  cpp_comments_only:
    enabled: true
    severity: info
    jsf_ref: "AV Rule 126"
    description: "Only C++ style comments (//) shall be used."

# ---------------------------------------------------------------------------
# Category 7: Class Design
# ---------------------------------------------------------------------------
classes:

  virtual_destructor_required:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 78"
    description: "All base classes with a virtual function shall define a virtual destructor."

  explicit_constructors:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 177"
    description: >
      Single-argument constructors should be marked explicit to prevent
      implicit conversions.

  no_public_data_in_classes:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 67"
    description: "Public data members should only be used in structs, not classes."

# ---------------------------------------------------------------------------
# Category 8: Embedded / Safety Specific
# ---------------------------------------------------------------------------
embedded:

  no_endian_assumptions:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 210"
    description: >
      Algorithms shall not make assumptions about byte ordering.
      Flag casts between pointer types and integer types for review.

  no_uninitialized_variables:
    enabled: true
    severity: error
    jsf_ref: "AV Rule 142"
    description: "All variables shall be initialized before use."

  no_unreachable_code:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 186"
    description: "There shall be no unreachable code."

  define_only_for_guards:
    enabled: true
    severity: warning
    jsf_ref: "AV Rule 29, 30, 31"
    description: >
      The #define directive shall only be used for include guards.
      Use constexpr for constants, inline functions for macros.

# ---------------------------------------------------------------------------
# Suppressions
# ---------------------------------------------------------------------------
suppressions:
  # Inline suppression comment marker.
  # Place "// NOLINT(rule_name)" at end of line to suppress.
  inline_marker: "NOLINT"

  # Files or directories to exclude from linting entirely.
  excluded_paths:
    - "third_party/"
    - "vendor/"
    - "test/"
    - "build/"