mcp-server-semgrep/semgrep-rules/ocaml/lang/best-practice/exception.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
  - id: bad-reraise
    patterns:
      - pattern: |
          raise $EXN
      - metavariable-regex:
          metavariable: $EXN
          regex: >-
            \A[a-z_][a-z_A-Z0-9']*\z

    message: >-
      You should not re-raise exceptions using 'raise' because it loses
      track of where the exception was raised originally, leading to
      a useless and possibly confusing stack trace.
      Instead, you should obtain a stack backtrace as soon as the
      exception is caught using 'try ... with exn -> let trace =
      Printexc.get_raw_backtrace () in ...', and keep
      it around until you re-raise the exception using
      'Printexc.raise_with_backtrace exn trace'.
      You must collect the stack backtrace before calling
      another function which might internally raise and catch
      exceptions.
      To avoid false positives from Semgrep, write
      'raise (Foo args)' instead of 'let e = Foo args in raise e'.

    languages: [ocaml]
    severity: WARNING
    metadata:
      category: best-practice
      technology:
        - ocaml
      references:
        - https://v2.ocaml.org/api/Printexc.html