This exception was surfaced thanks to switching a dumpn statement to dump in https://bugzilla.mozilla.org/show_bug.cgi?id=1581232

Note: the lack of prefix + final line break makes the log hard to parse visually I think we should really make sure we reintroduce those

STRs:

• open browser console

stdout will be filled with:

Got an exception: this._debuggerSourcesSeen is null
_addSource@resource://devtools/server/actors/thread.js:1981:7
onNewScript@resource://devtools/server/actors/thread.js:1940:10
_setup@resource://devtools/client/shared/sourceeditor/editor.js:350:27
appendToLocalElement@resource://devtools/client/shared/sourceeditor/editor.js:338:10
componentDidMount@resource://devtools/client/webconsole/components/Input/JSTerm.js:443:19
commitLifeCycles@resource://devtools/client/shared/vendor/react-dom.js:12949:22
commitAllLifeCycles@resource://devtools/client/shared/vendor/react-dom.js:14174:23
commitRoot@resource://devtools/client/shared/vendor/react-dom.js:14380:28
completeRoot/<@resource://devtools/client/shared/vendor/react-dom.js:15731:15
unstable_runWithPriority@resource://devtools/client/shared/vendor/react.js:617:12
completeRoot@resource://devtools/client/shared/vendor/react-dom.js:15730:27
performWorkOnRoot@resource://devtools/client/shared/vendor/react-dom.js:15659:21
performWork@resource://devtools/client/shared/vendor/react-dom.js:15567:24
performSyncWork@resource://devtools/client/shared/vendor/react-dom.js:15541:14
requestWork@resource://devtools/client/shared/vendor/react-dom.js:15410:5
scheduleWork@resource://devtools/client/shared/vendor/react-dom.js:15224:16
scheduleRootUpdate@resource://devtools/client/shared/vendor/react-dom.js:15865:15
updateContainerAtExpirationTime@resource://devtools/client/shared/vendor/react-dom.js:15881:10
updateContainer@resource://devtools/client/shared/vendor/react-dom.js:15908:10
ReactRoot.prototype.render@resource://devtools/client/shared/vendor/react-dom.js:16133:18
legacyRenderSubtreeIntoContainer/<@resource://devtools/client/shared/vendor/react-dom.js:16242:14
unbatchedUpdates@resource://devtools/client/shared/vendor/react-dom.js:15772:10
legacyRenderSubtreeIntoContainer@resource://devtools/client/shared/vendor/react-dom.js:16238:21
render@resource://devtools/client/shared/vendor/react-dom.js:16289:12
init/<@resource://devtools/client/webconsole/webconsole-wrapper.js:145:30
init@resource://devtools/client/webconsole/webconsole-wrapper.js:85:12
Async*init/this._initializer<@resource://devtools/client/webconsole/webconsole-ui.js:121:26
async*init@resource://devtools/client/webconsole/webconsole-ui.js:127:7
init@resource://devtools/client/webconsole/webconsole.js:112:20
init@resource://devtools/client/webconsole/browser-console.js:70:33
openBrowserConsole@resource://devtools/client/webconsole/browser-console-manager.js:67:15
toggleBrowserConsole/this._browserConsoleInitializing<@resource://devtools/client/webconsole/browser-console-manager.js:104:41
async*toggleBrowserConsole@resource://devtools/client/webconsole/browser-console-manager.js:106:7
openBrowserConsoleOrFocus@resource://devtools/client/webconsole/browser-console-manager.js:182:17
oncommand@resource://devtools/client/menus.js:130:29
EventListener.handleEvent*addTopLevelItems@resource://devtools/client/framework/browser-menus.js:250:16
exports.addMenus@resource://devtools/client/framework/browser-menus.js:301:19
_registerBrowserWindow@resource://devtools/client/framework/devtools-browser.js:534:18
@resource://devtools/client/framework/devtools-browser.js:886:22
load@resource://devtools/shared/base-loader.js:192:27
_require@resource://devtools/shared/base-loader.js:430:23
requireHook@resource://devtools/shared/Loader.jsm:90:14
require@resource://devtools/shared/base-loader.js:384:14
initDevTools@resource:///modules/DevToolsStartup.jsm:824:12
onPopupShowing@resource:///modules/DevToolsStartup.jsm:591:12
EventListener.handleEvent*hookWebDeveloperMenu@resource:///modules/DevToolsStartup.jsm:593:10
hookWindow@resource:///modules/DevToolsStartup.jsm:469:12
onWindowReady@resource:///modules/DevToolsStartup.jsm:414:10
_delayedStartup@chrome://browser/content/browser.js:2170:18
EventListener.handleEvent*onLoad@chrome://browser/content/browser.js:1918:12
EventHandlerNonNull*@chrome://browser/content/browser.xhtml:121:39

This seems to be BrowserConsole only, but we might want to fix it?

This is likely related to bug 1579046. I'm surprised I cannot reproduce though.

Are you on windows or have any prefs like browsertoolbox.fission?

nevermind, this is reproducing...

Thanks for providing a patch! I

https://hg.mozilla.org/mozilla-central/rev/e36f12d022bf