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events: make memory leak warning more programatically accessible #8298

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addaleax
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@addaleax addaleax commented Aug 27, 2016 •
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Checklist
  • make -j4 test (UNIX), or vcbuild test nosign (Windows) passes
  • tests and/or benchmarks are included
  • documentation is changed or added
  • commit message follows commit guidelines
Affected core subsystem(s)

events

Description of change

This makes the famous EventEmitter memory leak warnings occurring when the listener count for a given event exceeds a specified number more programatically accessible, by giving them properties referring to the event emitter instance and the event itself.

This can be useful for debugging the origins of such a warning when the stack itself doesn’t reveal enough information about the event emitter instance itself, e.g. when manual inspection of the
already-registered listeners is expected to be useful.

(It seems CI on this has to wait until Jenkins is running smoothly again…)
CI: https://ci.nodejs.org/job/node-test-commit/4794/

@addaleax
events: make memory leak warning more accessible
802e6be 
This makes the famous `EventEmitter memory leak` warnings occurring
when the listener count for a given event exceeds a specified number
more programatically accessible, by giving them properties referring
to the event emitter instance and the event itself.

This can be useful for debugging the origins of such a warning when
the stack itself doesn’t reveal enough information about the event
emitter instance itself, e.g. when manual inspection of the
already-registered listeners is expected to be useful.
@addaleax addaleax added events Issues and PRs related to the events subsystem / EventEmitter. semver-minor PRs that contain new features and should be released in the next minor version. labels Aug 27, 2016
@cjihrig
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cjihrig commented Aug 27, 2016

LGTM

jasnell
jasnell reviewed Aug 27, 2016
View reviewed changes
lib/events.js
`${existing.length} ${type} listeners added. ` +
'Use emitter.setMaxListeners() to increase limit');
w.name = 'Warning';
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Assigning a specific warning name would make differentiating a bit easier as well.

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+1 … but that would be a semver-major change?

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Yeah, good point. Nevermind then

On Saturday, August 27, 2016, Anna Henningsen [email protected]
wrote:

In lib/events.js
#8298 (comment):

                         `${existing.length} ${type} listeners added. ` +
                         'Use emitter.setMaxListeners() to increase limit');

  •    w.name = 'Warning';

+1 … but that would be a semver-major change?

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jasnell commented Aug 27, 2016

Couple of suggestions but otherwise LGTM

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LGTM if CI is green

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Landed in 932c824

@addaleax addaleax closed this Aug 30, 2016
addaleax added a commit that referenced this pull request Aug 30, 2016
@addaleax
events: make memory leak warning more accessible
932c824 
This makes the famous `EventEmitter memory leak` warnings occurring
when the listener count for a given event exceeds a specified number
more programatically accessible, by giving them properties referring
to the event emitter instance and the event itself.

This can be useful for debugging the origins of such a warning when
the stack itself doesn’t reveal enough information about the event
emitter instance itself, e.g. when manual inspection of the
already-registered listeners is expected to be useful.

PR-URL: #8298
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Jeremiah Senkpiel <[email protected]>
@addaleax addaleax deleted the events-warning branch August 30, 2016 15:17
addaleax added a commit to addaleax/node that referenced this pull request Aug 30, 2016
@addaleax
events: make memory leak warning name more verbose
a6b6114 
Switch from a generic `Warning` to the more specific
`MaxListenersExceededWarning`.

Ref: nodejs#8298
@addaleax addaleax mentioned this pull request Aug 30, 2016
Closed
4 tasks
addaleax added a commit that referenced this pull request Sep 4, 2016
@addaleax
events: make memory leak warning name more verbose
983775d 
Switch from a generic `Warning` to the more specific
`MaxListenersExceededWarning`.

Ref: #8298
PR-URL: #8341
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Evan Lucas <[email protected]>
@Fishrock123 Fishrock123 mentioned this pull request Sep 6, 2016
Closed
Fishrock123 pushed a commit to Fishrock123/node that referenced this pull request Sep 8, 2016
@addaleax @Fishrock123
events: make memory leak warning more accessible
8aebe10 
This makes the famous `EventEmitter memory leak` warnings occurring
when the listener count for a given event exceeds a specified number
more programatically accessible, by giving them properties referring
to the event emitter instance and the event itself.

This can be useful for debugging the origins of such a warning when
the stack itself doesn’t reveal enough information about the event
emitter instance itself, e.g. when manual inspection of the
already-registered listeners is expected to be useful.

PR-URL: nodejs#8298
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Jeremiah Senkpiel <[email protected]>
Fishrock123 pushed a commit that referenced this pull request Sep 9, 2016
@addaleax @Fishrock123
events: make memory leak warning more accessible
605db31 
This makes the famous `EventEmitter memory leak` warnings occurring
when the listener count for a given event exceeds a specified number
more programatically accessible, by giving them properties referring
to the event emitter instance and the event itself.

This can be useful for debugging the origins of such a warning when
the stack itself doesn’t reveal enough information about the event
emitter instance itself, e.g. when manual inspection of the
already-registered listeners is expected to be useful.

PR-URL: #8298
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Jeremiah Senkpiel <[email protected]>
@Fishrock123 Fishrock123 mentioned this pull request Sep 9, 2016
Merged
Fishrock123 added a commit that referenced this pull request Sep 14, 2016
@Fishrock123
2016-09-14, Version 6.6.0 (Current)
0a3ad92 
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
Fishrock123 added a commit to Fishrock123/node that referenced this pull request Sep 15, 2016
@Fishrock123
2016-09-14, Version 6.6.0 (Current)
ea2a309 
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
imyller added a commit to imyller/meta-nodejs that referenced this pull request Sep 15, 2016
@imyller
2016-09-14, Version 6.6.0 (Current)
99bfa4f 
    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 <[email protected]>
imyller added a commit to imyller/meta-nodejs that referenced this pull request Sep 15, 2016
@imyller
2016-09-14, Version 6.6.0 (Current)
f31a04d 
    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 <[email protected]>
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@addaleax @cjihrig @jasnell @Fishrock123