ocaml.lang.best-practice.hashtbl.hashtbl-find-outside-try

profile photo of semgrepsemgrep
Author
4,866
Download Count*
LGPL Commons Clause
License

You should not use Hashtbl.find outside of a try, or you should use Hashtbl.find_opt

Run Locally

Run in CI

Semgrep CI docs

Defintion

Edit RuleView Source
Open in Playground 
rules:
  - id: hashtbl-find-outside-try
    patterns:
      - pattern: |
          Hashtbl.find ...
      - pattern-not-inside: |
          try ... with ... -> ...
      - pattern-not-inside: |
          match ... with | ... -> ...
    message: You should not use Hashtbl.find outside of a try, or you should use
      Hashtbl.find_opt
    languages:
      - ocaml
    severity: WARNING
    metadata:
      category: best-practice
      technology:
        - ocaml
      license: Commons Clause License Condition v1.0[LGPL-2.1-only]

Examples

hashtbl.ml

let test1 xs =
  (* ruleid:hashtbl-find-outside-try *)
  if Hashtbl.find h 1
  then 1
  else 2

let test2 xs =
 (* ok *)
 try
   if Hashtbl.find h 1
   then 1
   else 2
 with Not_found -> 3

let test3 xs =
 (* ok *)
 match Hashtbl.find h 1 with
 | true -> 1
 | false -> 2
 | exception Not_found -> 3