Originally posted in https://bugzilla.mozilla.org/show_bug.cgi?id=1430810#c12: After re-testing with Bug 1433625 resolved I'm now seeing a different error on both devtools/client/webconsole/test/browser_console_consolejsm_output.js and with the LightweightThemeManager example script in Comment 10. If I include these lines in LightweightThemeManager.jsm: console.log("LightweightThemeManager.jsm"); console.time("LightweightThemeManager.jsm timer"); console.timeEnd("LightweightThemeManager.jsm timer"); Then when I `./mach run --jsconsole` I see an error in the Browser Console: Error: Timer “LightweightThemeManager.jsm timer” doesn’t exist. Stack trace: logConsoleAPIMessage@resource://devtools/shared/base-loader.js -> resource://devtools/client/webconsole/webconsole.js:1278:25 _outputMessageFromQueue@resource://devtools/shared/base-loader.js -> resource://devtools/client/webconsole/webconsole.js:2103:16 _flushMessageQueue@resource://devtools/shared/base-loader.js -> resource://devtools/client/webconsole/webconsole.js:1992:20 We are receiving this packet from the actor which means we are somehow hitting the eTimerDoesntExist case in Console.cpp: { "addonId": "", "arguments": [ "LightweightThemeManager.jsm timer" ], "columnNumber": 3, "counter": null, "filename": "resource://gre/modules/LightweightThemeManager.jsm", "functionName": "", "groupName": "", "level": "timeEnd", "lineNumber": 20, "prefix": "", "private": false, "timeStamp": 1517266277688, "timer": { "error": "timerDoesntExist", "name": "LightweightThemeManager.jsm timer" }, "workerType": "none", "styles": [], "category": "webdev", "_type": "ConsoleAPI" } Here's the interesting thing - If I do this script instead it works just as expected: var c = console.createInstance(); c.log("LightweightThemeManager.jsm"); c.time("LightweightThemeManager.jsm timer"); c.timeEnd("LightweightThemeManager.jsm timer"); So I guess this only is an issue when using the webidl console global directly from a JSM, and it's not a problem when first calling createInstance.

Moving needinfo from Bug 1430810

We need to have BackstagePass CCed in order to implement this feature.