promise: warning on unhandled rejection (v6.x) by jasnell · Pull Request #8223 · nodejs/node

jasnell · 2016-08-22T16:31:49Z

Checklist

make -j4 test (UNIX), or vcbuild test nosign (Windows) passes
tests and/or benchmarks are included
commit message follows commit guidelines

Affected core subsystem(s)

promises

Description of change

A semver-minor port of #8217 for v6.x (it does not include the deprecation). This will be kept up to date along with #8217 as nits are addressed. This should not land until #8217 lands.

ChALkeR · 2016-08-22T21:53:45Z

Blocked only because

This should not land until #8217 lands.

So that won't be missed.

jasnell · 2016-08-29T23:35:31Z

I need to update this before it can land...

Log unhandled promise rejections with a guid and emit a process warning. When rejection is eventually handled, emit a secondary warning. PR-URL: nodejs#8217 Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

jasnell · 2016-08-30T17:49:38Z

#8217 landed, this PR has been updated. @ChALkeR @Fishrock123 @benjamingr @chrisdickinson ... PTAL

Fishrock123 · 2016-08-30T18:44:13Z

lib/internal/process/promises.js

+      const reason = pendingUnhandledRejections.shift();
      if (hasBeenNotifiedProperty.get(promise) === false) {
        hasBeenNotifiedProperty.set(promise, true);
+        const uid = promiseToGuidProperty.get(promise);


Get inside the following if?

Fishrock123 · 2016-08-30T18:45:21Z

LGTM w/ CI: https://ci.nodejs.org/job/node-test-pull-request/3894/

jasnell · 2016-08-30T19:58:48Z

CI is green. Will land either tomorrow or Thursday if there are no objections.

benjamingr · 2016-08-31T06:32:48Z

LGTM

chrisdickinson · 2016-08-31T17:11:18Z

LGTM

Log unhandled promise rejections with a guid and emit a process warning. When rejection is eventually handled, emit a secondary warning. PR-URL: #8223 Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>

jasnell · 2016-08-31T17:36:26Z

Landed in v6.x in 180867d

Notable changes: * crypto: Added `crypto.timingSafeEqual()`. (not-an-aardvark) #8304 * events: Made the "max event listeners" memory leak warning more accessible. (Anna Henningsen) #8298 * promises: Unhandled rejections now emit a process warning after the first tick. (Benjamin Gruenbaum) #8223 * repl: Added auto alignment for `.editor` mode. (Prince J Wesley) #8241 * util: Some functionality has been added to `util.inspect()`: - Returning `this` from a custom inspect function now works. (Anna Henningsen) #8174 - Added support for Symbol-based custom inspection methods. (Anna Henningsen) #8174 Refs: #8428 Refs: #8457 PR-URL: #8466

Notable changes: * crypto: Added `crypto.timingSafeEqual()`. (not-an-aardvark) nodejs#8304 * events: Made the "max event listeners" memory leak warning more accessible. (Anna Henningsen) nodejs#8298 * promises: Unhandled rejections now emit a process warning after the first tick. (Benjamin Gruenbaum) nodejs#8223 * repl: Added auto alignment for `.editor` mode. (Prince J Wesley) nodejs#8241 * util: Some functionality has been added to `util.inspect()`: - Returning `this` from a custom inspect function now works. (Anna Henningsen) nodejs#8174 - Added support for Symbol-based custom inspection methods. (Anna Henningsen) nodejs#8174 Refs: nodejs#8428 Refs: nodejs#8457 PR-URL: nodejs#8466

Notable changes: * crypto: Added `crypto.timingSafeEqual()`. (not-an-aardvark) nodejs/node#8304 * events: Made the "max event listeners" memory leak warning more accessible. (Anna Henningsen) nodejs/node#8298 * promises: Unhandled rejections now emit a process warning after the first tick. (Benjamin Gruenbaum) nodejs/node#8223 * repl: Added auto alignment for `.editor` mode. (Prince J Wesley) nodejs/node#8241 * util: Some functionality has been added to `util.inspect()`: - Returning `this` from a custom inspect function now works. (Anna Henningsen) nodejs/node#8174 - Added support for Symbol-based custom inspection methods. (Anna Henningsen) nodejs/node#8174 Signed-off-by: Ilkka Myller <ilkka.myller@nodefield.com>

As discovered in 18F#51, the `UnhandledPromiseRejectionWarning` and `PromiseRejectionHandledWarning` warnings were apparently added in v6.6.0 (https://nodejs.org/en/blog/release/v6.6.0/); specifically it was added by nodejs/node#8223. See also: nodejs/node#6439 nodejs/node#8217 https://nodejs.org/dist/latest-v6.x/docs/api/process.html#process_event_unhandledrejection https://nodejs.org/dist/latest-v6.x/docs/api/process.html#process_event_rejectionhandled https://nodejs.org/dist/latest-v6.x/docs/api/process.html#process_event_warning Test failures from `test/integration-test.js` after upgrading to Node v6.9.1 showed extra output such as: ``` (node:39696) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): null (node:39696) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 2) ``` This was happening because `scripts/slack-github-issues.js` created a Hubot listener that returned a `Promise` so that the integration test could use `.should.be.rejectedWith` assertions. Rather than jump through hoops to quash the warnings, this change now causes the listener's `catch` handler to return the result of the rejected `Promise`, converting it to a fulfilled `Promise` in the process. Since Hubot never used the result anyway, the only effect it has in production is to eliminate the warning messages. The tests now just check that the `Promise` returned by the listener callback is fulfilled with the expected error result, with practically no loss in clarity.

Backported from mbland/hubot-slack-github-issues#7. As discovered in 18F/hubot-slack-github-issues#51, the `UnhandledPromiseRejectionWarning` and `PromiseRejectionHandledWarning` warnings were apparently added in v6.6.0 (https://nodejs.org/en/blog/release/v6.6.0/); specifically it was added by nodejs/node#8223. See also: nodejs/node#6439 nodejs/node#8217 https://nodejs.org/dist/latest-v6.x/docs/api/process.html#process_event_unhandledrejection https://nodejs.org/dist/latest-v6.x/docs/api/process.html#process_event_rejectionhandled https://nodejs.org/dist/latest-v6.x/docs/api/process.html#process_event_warning A test failure from `solutions/06-integration/test/integration-test.js` after upgrading to Node v6.9.1 showed output such as: ``` - "(node:87412) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 14): Error: failed to create a GitHub issue in 18F/handbook: received 500 response from GitHub API: {\"message\":\"test failure\"}\n" ``` This was happening because `scripts/slack-github-issues.js` ignored the return value from `Middleware.execute()`, whether it was undefined or a `Promise`. For consistency's sake (and to provide a clearer upgrade path to the current state of mbland/slack-github-issues), `Middleware.execute()` always returns a `Promise`, and `scripts/slack-github-issues.js` handles and ignores any rejected Promises. This fixed the `integration-test.js` error, but also required minor updates to `solutions/{05-middleware,complete}/test/middleware-test.js`. The next commit will update the tutorial narrative to account for this change.

jasnell added semver-minor PRs that contain new features and should be released in the next minor version. process Issues and PRs related to the process subsystem. promises Issues and PRs related to ECMAScript promises. labels Aug 22, 2016

ChALkeR added the blocked PRs that are blocked by other issues or PRs. label Aug 22, 2016

jasnell added the wip Issues and PRs that are still a work in progress. label Aug 29, 2016

jasnell force-pushed the warn-on-unhandled-rejection branch from 296fc71 to 995d504 Compare August 30, 2016 17:48

jasnell removed the blocked PRs that are blocked by other issues or PRs. label Aug 30, 2016

Fishrock123 reviewed Aug 30, 2016
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jasnell closed this Aug 31, 2016

Fishrock123 mentioned this pull request Sep 9, 2016

v6.6.0 proposal #8466

Merged

ChALkeR removed the wip Issues and PRs that are still a work in progress. label Sep 9, 2016

ChALkeR mentioned this pull request Sep 9, 2016

Default Unhandled Rejection Behavior nodejs/promises#26

Closed

mbland mentioned this pull request Nov 23, 2016

[Question] Still necessary to use a fork? 18F/hubot-slack-github-issues#51

Closed

mbland mentioned this pull request Dec 1, 2016

Integration test fixes in light of new Promise warnings mbland/hubot-slack-github-issues#7

Merged

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promise: warning on unhandled rejection (v6.x)#8223

promise: warning on unhandled rejection (v6.x)#8223
jasnell wants to merge 1 commit intonodejs:v6.xfrom
jasnell:warn-on-unhandled-rejection

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