then warning creates messy logs for thenable APIs

The recent addition of warnings when then is called with a non function argument is creating messy test output over at Knex. The basic issue here is that query objects are thenables that proxy to a real promise which gets created. Since Promise.longStackTraces turns on debugging, we’re getting loads of warnings about empty thens in the integration tests.

The easy fix here is just to revert the warning, but I understand if there was a compelling reason to do it. We could also use promise.then.apply(promise, arguments) in place of explicitly passing the two callbacks to promise.then. I’d prefer not to go that route since it’s harder to read/understand.

[petkaantonov]

@bendrucker You could just call ._then? It’s forced to retain same api signature across all versions, even major.

btw In 3.0 warnings are disabled/enabled with

Promise.config({
     warnings: false,
     longStackTraces: true
});

Note that .then() doesn’t cause a warning, in fact it’s used internally many times. Warning is only given when you explicitly pass value(s) that are all non-functions.

[bendrucker]

Fair enough. I’ve fixed it in knex.