Maximum call stack size exceeded

[jiutianxuannan]

new sharedb.Connection(this.socket)

[alecgibson]

Going to need a bit more information than this, please.

[maxfortun]

I am not sure if this is the same issue that the original author is facing, but I just hit the same error message.
I am not sure how to replicate this, but here are some observations.

Stack trace:

RangeError: Maximum call stack size exceeded
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:196:22)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3
    at next (/root/apps/djsp-cfg-pubedit-sh-svc-sharedb/node_modules/sharedb/lib/backend.js:200:5)
    at /root/apps/djsp-cfg-pubedit-sh-svc-sharedb/bin/www:122:3

The code at www:122 is calling next().

backend.use('submit', (context, next) => {
  Object.assign(context.op.m, context.agent.custom);
  context.opMetadataProjection = { username: true };
  next();
 });

The code at backend.js:200 is calling fn(request, next):

sharedb/lib/backend.js

Lines 186 to 203 in 3e636d0

	Backend.prototype.trigger = function(action, agent, request, callback) {
	request.action = action;
	request.agent = agent;
	request.backend = this;
	var fns = this.middleware[action];
	if (!fns) return callback();
	// Copying the triggers we'll fire so they don't get edited while we iterate.
	fns = fns.slice();
	var next = function(err) {
	if (err) return callback(err);
	var fn = fns.shift();
	if (!fn) return callback();
	fn(request, next);
	};
	next();
	};

From what I can tell, the next, since it is defined in the outer block with var, is global scoped, and thus when it is passed into fn() has the prior state. That aside, I do not fully understand what this code is trying to achieve. It is defining next as a function, and then calling the next it is defining from its own definition. It doesn't look to be intentional.

[maxfortun]

Looks like instead of passing next, the code should be passing callback. Adding fix to [#513].

sharedb/lib/backend.js

Line 200 in cddf66c

fn(request, callback);

[alecgibson]

I left a comment on #513 but reiterating here: I think we should open a separate PR for this change to discuss. As a heads-up, I won't have time until next week to look at it properly.