intermittent "docShell.chromeEventHandler is null" w/blank devtools window

[mykmelez]

@jryans, @ochameau: Sometimes on startup I see this stack dumped to the terminal window, and the devtools window is blank:

A coding exception was thrown and uncaught in a Task.

Full message: TypeError: docShell.chromeEventHandler is null
Full stack: Helpers_onLocationChange@resource://devtools/client/shared/DOMHelpers.jsm:159:7
Toolbox.prototype.open/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/toolbox.js:371:7
TaskImpl_run@resource://gre/modules/Task.jsm:319:40
Handler.prototype.process@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:937:23
this.PromiseWalker.walkerLoop@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:816:7
Promise*this.PromiseWalker.scheduleWalkerLoop@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:747:11
this.PromiseWalker.schedulePromise@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:779:7
Promise.prototype.then@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:454:5
TaskImpl_handleResultValue@resource://gre/modules/Task.jsm:395:7
TaskImpl_run@resource://gre/modules/Task.jsm:327:13
TaskImpl@resource://gre/modules/Task.jsm:280:3
createAsyncFunction/asyncFunction@resource://gre/modules/Task.jsm:254:14
Task_spawn@resource://gre/modules/Task.jsm:168:12
Toolbox.prototype.open@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/toolbox.js:357:12
DevTools.prototype.showToolbox@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/devtools.js:435:7
this.gDevTools[name]@resource://devtools/client/framework/gDevTools.jsm:107:12
toolboxOpened<@chrome://devtools/content/framework/toolbox-init.js:87:14
TaskImpl_run@resource://gre/modules/Task.jsm:319:40
Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:937:23
this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:816:7
Promise*this.PromiseWalker.scheduleWalkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:747:11
this.PromiseWalker.schedulePromise@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:779:7
this.PromiseWalker.completePromise@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:714:7
Handler.prototype.process@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:937:23
this.PromiseWalker.walkerLoop@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:816:7
Promise*this.PromiseWalker.scheduleWalkerLoop@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:747:11
this.PromiseWalker.schedulePromise@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:779:7
this.PromiseWalker.completePromise@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/Promise-backend.js:714:7
TabTarget.prototype.makeRemote/onConsoleAttached@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target.js:410:7
DebuggerClient.prototype.attachConsole/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:552:7
resolve@resource://devtools/shared/deprecated-sync-thenables.js:40:40
then@resource://devtools/shared/deprecated-sync-thenables.js:20:43
resolve@resource://devtools/shared/deprecated-sync-thenables.js:72:11
listenerJson@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:740:9
emitOnObject@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:112:9
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:89:38
Request.prototype.emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1234:29
DebuggerClient.prototype.onPacket/emitReply@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1018:29
DevTools RDP*DebuggerClient.prototype.request@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:724:5
DebuggerClient.prototype.attachConsole@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:542:12
TabTarget.prototype.makeRemote/attachConsole@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target.js:414:7
TabTarget.prototype.makeRemote/attachTab/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target.js:400:9
DebuggerClient.prototype.attachTab/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:467:7
resolve@resource://devtools/shared/deprecated-sync-thenables.js:40:40
then@resource://devtools/shared/deprecated-sync-thenables.js:20:43
resolve@resource://devtools/shared/deprecated-sync-thenables.js:72:11
listenerJson@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:740:9
emitOnObject@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:112:9
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:89:38
Request.prototype.emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1234:29
DebuggerClient.prototype.onPacket/emitReply@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1018:29
DevTools RDP*DebuggerClient.prototype.request@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:724:5
DebuggerClient.prototype.attachTab@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:461:12
TabTarget.prototype.makeRemote/attachTab@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target.js:392:7
TabTarget.prototype.makeRemote@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target.js:432:7
exports.TargetFactory.forRemoteTab@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target.js:59:23
exports.targetFromURL<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target-from-url.js:118:10
TaskImpl_run@resource://gre/modules/Task.jsm:319:40
resolve@resource://devtools/shared/deprecated-sync-thenables.js:40:40
then@resource://devtools/shared/deprecated-sync-thenables.js:20:43
resolve@resource://devtools/shared/deprecated-sync-thenables.js:72:11
listenerJson@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:740:9
emitOnObject@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:112:9
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:89:38
Request.prototype.emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1234:29
DebuggerClient.prototype.onPacket/emitReply@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1018:29
DevTools RDP*DebuggerClient.prototype.request@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:724:5
RootClient.prototype.getWindow@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1674:12
exports.targetFromURL<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/target-from-url.js:102:28
TaskImpl_run@resource://gre/modules/Task.jsm:319:40
resolve@resource://devtools/shared/deprecated-sync-thenables.js:40:40
then@resource://devtools/shared/deprecated-sync-thenables.js:20:43
resolve@resource://devtools/shared/deprecated-sync-thenables.js:72:11
DebuggerClient.prototype.connect/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:360:7
eventSource/aProto.addOneTimeListener/l@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:68:7
eventSource/aProto.emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:131:9
exports.DebuggerClient/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:227:5
emitOnObject@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:112:9
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:89:38
Request.prototype.emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1234:29
DebuggerClient.prototype.onPacket/emitReply@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1018:29
DebuggerClient.prototype.onPacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/client/main.js:1023:9
LocalDebuggerTransport.prototype.send/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/transport/transport.js:569:11
exports.makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/ThreadSafeDevToolsUtils.js:101:14
exports.makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/ThreadSafeDevToolsUtils.js:101:14

[jryans]

I have noticed this intermittently as well. Hope to check it out soon.

[jryans]

@mykmelez, is this something you still see lately? I have not seen it recently myself.

[mykmelez]

I've seen it in the recent past, although perhaps not in the last couple of days. The last few times I saw it, it always happened the first time I ran Positron after rebuilding, so it might be related to a part of the build process.

In any case, let's close it for now, then reopen if it recurs.

[mykmelez]

I just hit this again. 😞