# S1314 / M23_035: Octal values should not be used
id: no-octal-literals
name: Octal Values Should Not Be Used
severity: error
category: maintainability
defect_class: correctness
inline_tier: blocking
language: c

message: "octal literal detected — use decimal or hexadecimal instead"

description: |
  Octal literals (leading zero) are easily confused with decimal literals.
  A typo like `012` instead of `12` can cause subtle bugs.

  ✅ FIX: Remove the leading zero or use 0x prefix for hex

  ```c
  int mode = 12;    // GOOD - decimal
  int flags = 0xA;  // GOOD - hex
  ```

query: |
  (number_literal) @NUM

metavars:
  - NUM

post_filter: c_octal_literal

tags:
  - maintainability
  - c
  - misra
  - pitfall

examples:
  bad: |
    int x = 010;   // BAD - octal (value 8)
    int y = 007;   // BAD - octal (value 7)

  good: |
    int x = 10;    // GOOD - decimal
    int y = 0x10;  // GOOD - hex

has_fix: false