New Issue: [Bug]: throwing hash functions generate an unavoidable error in error handling relaxed mode

Notifications Issues
1

24882, "lydia-duncan", "[Bug]: throwing hash functions generate an unavoidable error in error handling relaxed mode", "2024-04-17T22:08:06Z"

Summary of Problem

Description:
The user can define a hash function that throws, but only so long as the hash function is not defined inside a module. Once the code is in a module, "relaxed" mode error handling will cause the compiler-generated hash function that calls the user-defined one to generate an error. Since the function is compiler generated, the user cannot resolve this issue themselves

Is this a blocking issue with no known work-arounds?
There are workarounds, but they are not great imo:

  • Make the hash function halt instead of throw
    • Thwarts the ability to handle errors, which a user probably would want to do (since they marked the function as throwing to begin with)
  • Don't wrap the code containing the hash function in a module
    • Makes it less obvious how to access the code inside the module. Still possible, but forces the user to use a less polished structure for their project
  • Make the module a prototype module
    • Means the entire module cannot get checked for stricter error-handling. Note that this also applies to the previous work-around

Steps to Reproduce

Source Code:

module throwingHashInModule { // module decl essential to exhibit the problem
  record myRec: hashable {
    var x: int;

    proc hash(salt = 0): uint throws {
      // This is not meant to be a good hash function, just to test throwing
      if (salt == 0) then throw new IllegalArgumentError("salt too obvious!");
      else return x*salt;
    }
  }

  proc main() {
    var myR = new myRec(15);
    try {
      var hash1 = myR.hash();
    } catch e: IllegalArgumentError {
      writeln(e.message());
      var hash2 = try! myR.hash(3);
      writeln(hash2);
    } catch e {
      halt(e.message());
    }
  }
}

Compile command:
chpl foo.chpl

Execution command:
N/A

Associated Future Test(s):
test/hash/throwingHashInModule.chpl #TBD

Configuration Information

  • Output of chpl --version: chpl version 2.1.0 pre-release
  • Output of $CHPL_HOME/util/printchplenv --anonymize: Should be any
  • Back-end compiler and version, e.g. gcc --version or clang --version: N/A
  • (For Cray systems only) Output of module list: N/A