~ + Tab -> Focus lost (onKeyDown_ triggered twice for Tab key)

[chabou]

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate

• OS version and name: MacOS 10.11.6
• Hyper.app version: Master but present in 1.0.1
• Link of a Gist with the contents of your .hyper.js: default
• Relevent information from devtools (CMD+SHIFT+I on Mac OS, CTRL+SHIFT+I elsewhere): See below
• The issue is reproducible in vanilla Hyper.app: yes

Issue

The problem is : If a "composition", beginning with ~ for example, is ended with Tab and not Space, Term loose focus (hyperCaret receive a blur event).

After blur event, if I press Tab twice, focus come back. (same as #1273)

More interesting: If I have another pane, focus goes to the other pane (without highlight menu) !! After that, If a do the same on the other pane, focus disappear, press 'tab' twice and he goes back to first pane.

I tracked down this bug and it drove me nuts...

Here is what I found:

hterm.js?8d82:204 onKeyDown_ KeyboardEvent {isTrusted: true, key: "Alt", code: "AltLeft", location: 1, ctrlKey: false…}
hterm.js?8d82:204 onKeyDown_ KeyboardEvent {isTrusted: true, key: "Dead", code: "KeyN", location: 0, ctrlKey: false…}
hterm.js?8d82:204 onKeyDown_ KeyboardEvent {isTrusted: true, key: "Tab", code: "Tab", location: 0, ctrlKey: false…}
index.js?bb83:6001 No definition for keyCode: 229
hterm.js?8d82:122 onTextInput_ TextEvent {isTrusted: true, data: "~", view: Window, detail: 0, which: 0…}
core.js?dfa1:97  action @ 23:57:52.611 SESSION_USER_DATA
hterm.js?8d82:204 onKeyDown_ KeyboardEvent {isTrusted: true, key: "Tab", code: "Tab", location: 0, ctrlKey: false…}
hterm.js?8d82:206 onKeyDown emitted twice
hterm.js?8d82:370 -> BLUR

onKeyDown_ function is called twice with the same event (same e.timeStamp value). If preventDefault() is called on it, blur do not happen.

I tried to debug step by step BUT if I add a breakpoint in onTextInput_function, this bug disappear 😱

Difference I noticed:
Without breakpoint HyperCarret input eventListener is called right after SESSION_USER_DATA redux action and before SESSION_ADD_DATA action.
But with a breakpoint, the call occurs after SESSION_ADD_DATA and SESSION_PTY_DATA actions

Maybe, webview think that I have Alt pressed with Tab. And in Chrome Alt+Tab give focus to the next Link. So Caret and Tabheader maybe ?

If someone can help me, because I'm on the brink of sending a PR with this ugly e.preventDefault(); 😂

[albinekb]

Oh so this is what I'm seeing too! Cool that you found what's broken!

If someone can help me, because I'm on the brink of sending a PR with this ugly e.preventDefault(); 😂

That's not so ugly? 🤔 Or will it break other things?

[chabou]

"ugly" fix will not break anything but it more like a protection than a real solution. Maybe this repeated event breaks something else before we stop his propagation.
It might be better to prevent this race condition than to protect against it. But I spent enough hours on it to accept this protection as a solution 😥
If someone want to further investigate... In the meantime, I'll made a PR with this protection