emscripten-core/emscripten

Cryptic `sig is undefined` error in reportUndefinedSymbols() if function signature not available

Open

#17,283 opened on Jun 21, 2022

View on GitHub
 (0 comments) (0 reactions) (0 assignees)C++ (27,361 stars) (3,519 forks)batch import
good first bughelp wanted

Description

Discussed in https://github.com/emscripten-core/emscripten/discussions/17266

Originally posted by johnwason June 18, 2022 Currently if a function signature is not defined, reportUndefinedSymbols() will simple raise an error sig is undefined, which is not at all helpful. An error handler should be added to check if the value passed to addFunction() does not have sig defined, and report something more useful to the user. See #17264

Contributor guide

Tech stack
ccppjavascriptwasm
Domain
backendtoolingdeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
JavaScriptEmscripten basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Locate the `reportUndefinedSymbols()` function in Emscripten's JavaScript runtime code. The function currently raises a cryptic 'sig is undefined' error when a function signature is not provided. Review the related discussion (#17266) and issue (#17264) for background. Add a check to verify that `sig` is defined before using it, and provide a more informative error message indicating which function lacks a signature. The fix is likely in a single file within the Emscripten source tree.