test: http2 rstStream duplicate call #16217

trivikr · 2017-10-15T09:50:24Z

This commit fixes an issue with rstStream() which checked incorrect value of rst. It also adds a test case for this fix

Lines 928 to 933 in 411695e

    
           if (this[kState].rst) { 
        
             // rst has already been called, do not call again, 
        
             // skip straight to destroy 
        
             stream.destroy(); 
        
             return; 
        
           }

Refs: #14985

Checklist

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

Affected core subsystem(s)

test, http2

apapirovski

Looks great! Just a minor nit.

apapirovski · 2017-10-15T15:47:42Z

test/parallel/test-http2-client-rststream-before-connect.js

+  req._destroy = common.mustCall(req._destroy.bind(req), 2);
+
+  client.rstStream(req, 0);
+  // redundant call to rstStream to test rst won't be called again
  client.rstStream(req, 0);


If you call the second client.rstStream with a different code, you could then verify that the rstCode didn't get set to the 2nd incorrect code (the strictEqual check below will do the job). Right now it's a bit ambiguous as to whether it does or not.

I've updated the second call to send different code (number 1) which is not updated in req.rstCode

apapirovski · 2017-10-15T15:47:50Z

lib/internal/http2/core.js

@@ -925,7 +925,7 @@ class Http2Session extends EventEmitter {
                                 'number');
    }

-    if (this[kState].rst) {
+    if (stream[kState].rst) {


Nice catch!

Thanks! :-)

This commit fixes an issue with rstStream() which checked incorrect value of rst. It also adds a test case for this fix Refs: nodejs#14985

mcollina · 2017-10-17T08:01:43Z

test/parallel/test-http2-client-rststream-before-connect.js

@@ -15,12 +15,15 @@ server.on('listening', common.mustCall(() => {
  const client = h2.connect(`http://localhost:${server.address().port}`);

  const req = client.request({ ':path': '/' });
+  // make sure that destroy is called twice
+  req._destroy = common.mustCall(req._destroy.bind(req), 2);


I am a bit lost in how this is possible, in theory it is protected from running _destroy twice: https://github.com/nodejs/node/blob/master/lib/internal/streams/destroy.js#L10-L30

It was confusing for me too.
The two instances where stream.destroy() is called are:

in first call of rstStream()

node/lib/internal/http2/core.js

Line 631 in ff747e3

stream.destroy();

in second call of rstStream()

node/lib/internal/http2/core.js

Line 931 in ff747e3

stream.destroy();

This might translate to two calls of req._destroy?

I've run the test on repeat 100 times to confirm that it it succeeds using the following command:

> python tools/test.py -J --mode=release parallel/test-http2-client-rststream-before-connect --repeat 100 [00:06|% 100|+ 100|- 0]: Done

I believe @mcollina is right. I think what's happening is that this line is accounting for the 2 triggers of _destroy:

node/lib/internal/http2/core.js

Lines 1494 to 1498 in ff747e3

if (this[kID] === undefined) {

debug(`[${sessionName(session[kType])}] queuing destroy for new stream`);

this.once('ready', this._destroy.bind(this, err, callback));

return;

}

The reason that it's different than before is because the declaration was moved before client.rstStream() instead of after. I think that stream.destroy() isn't even necessary and it should just be the empty return;.

ping @jasnell — any thoughts re: whether that stream.destroy() serves an actual purpose?

I've run the test on repeat 100 times

@trivikr the test might be passing, but I'm wondering if the actual behavior is correct.

I don't think that calling rstStream() twice should destroy the stream. It seems a not needed side effect. I think it should throw.

node/lib/internal/http2/core.js

Lines 929 to 931 in ff747e3

// rst has already been called, do not call again,

// skip straight to destroy

stream.destroy();

cc @jasnell

@mcollina I ran the test on repeat 100 times to check if there's any flakiness in it.
I'll wait for the response from @jasnell and update the code and test as per the recommendation at the end of the discussion.

I'll dig in on this a bit more later on today

BridgeAR · 2017-10-18T15:01:09Z

I would argue that this actually is a http2 fix and not a test change. So the http2 subsystem should be used instead.

apapirovski

Just making it explicit this shouldn't land until the _destroy situation is addressed, one way or another.

trivikr · 2017-10-25T18:24:52Z

Any update on this request?

apapirovski · 2017-11-07T17:22:32Z

Fixed in #16753

nodejs-github-bot added dont-land-on-v4.x http2 Issues or PRs related to the http2 subsystem. labels Oct 15, 2017

apapirovski approved these changes Oct 15, 2017

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test: http2 rstStream duplicate call

810edb8

This commit fixes an issue with rstStream() which checked incorrect value of rst. It also adds a test case for this fix Refs: nodejs#14985

trivikr force-pushed the test-http2-client-rststream branch from 7e7f4d6 to 810edb8 Compare October 15, 2017 16:05

jasnell approved these changes Oct 15, 2017

View reviewed changes

lpinca approved these changes Oct 16, 2017

View reviewed changes

mcollina reviewed Oct 17, 2017

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apapirovski suggested changes Oct 19, 2017

View reviewed changes

apapirovski closed this Nov 7, 2017

trivikr deleted the test-http2-client-rststream branch November 7, 2017 18:54

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test: http2 rstStream duplicate call #16217

test: http2 rstStream duplicate call #16217

trivikr commented Oct 15, 2017

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trivikr commented Oct 25, 2017

apapirovski commented Nov 7, 2017

	if (this[kState].rst) {
	// rst has already been called, do not call again,
	// skip straight to destroy
	stream.destroy();
	return;
	}

	if (this[kID] === undefined) {
	debug(`[${sessionName(session[kType])}] queuing destroy for new stream`);
	this.once('ready', this._destroy.bind(this, err, callback));
	return;
	}

test: http2 rstStream duplicate call #16217

test: http2 rstStream duplicate call #16217

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trivikr commented Oct 15, 2017

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Affected core subsystem(s)

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