compat-table/node-compat-table

Duplicate identifier: why should the first test pass?

Open

#87 opened on Aug 4, 2023

View on GitHub
 (1 comment) (0 reactions) (0 assignees)HTML (34 forks)github user discovery
bughelp wanted

Repository metrics

Stars
 (874 stars)
PR merge metrics
 (PR metrics pending)

Description

function(){
try {
  eval('var d = function d([d]) { return d };if (d([true]) !== true) return false;');
} catch (e) {
  return !(e instanceof SyntaxError);
}

try {
  eval('var f = function f([id, id]) { return id }');
  return false;
} catch (e) {
  return e instanceof SyntaxError;
}
}

In the first try/catch block, it evaluates several statements with eval. One of the statements has return false; in it, which is a syntax error because the top level of code evaluated by eval isn't a function. Is this intentional?

The line seems to have changed recently in https://github.com/williamkapke/node-compat-table/commit/39a4e84b716a12273ec6c96276b460660345b742, which seems to have tried to wrap the code in an eval so that the SyntaxError can be caught and returned as false. However, in doing so, it made versions that formerly pass now fail:

https://github.com/williamkapke/node-compat-table/commit/39a4e84b716a12273ec6c96276b460660345b742#diff-360bd21e67071c3b8fd48a96bdadbcee20a6ec434aeffb7cd1a0c528ad1644f2L432-R432

Contributor guide

Research direction
Examine the commit that changed the test and verify the expected behavior for the first try/catch block. Determine if the 'return false' is a syntax error in eval context and how the test should be structured to correctly test for duplicate identifiers.
Tech stack
javascript
Domain
testing
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60