saved browsers settings

[tanmoyAtb]

closes #847

[render]

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[render]

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[Tbaut]

Instead of having many comments and suggestions, I pushed the following changes, that should not change any logic:

• code styling nits
• use useCallback and promise.then.catch when only 1 await was used
• console.error in promise
• show the hour when the browser got added
• use CSS instead of  
• removed a weird await (here) before promise.then.catch and added a .finally

[Tbaut]

Now I've tested the functionality and there's something that either I don't understand, or that doesn't work:
I had 2 browser saved, I downloaded the backup phrases, and deleted the browser shares:

If I refresh, I'm still logged-in automatically -> from my understanding this shouldn't be possible
If I manually log-out, then try to login and chose to use a backup phrase, both backup phrases that I just downloaded don't work.
I login with the password then, that works, I'm not asked to save the browser, and I end up with the same settings as the screenshot above, refreshing logs me in automatically, so I think my browser definitely got saved.

[FSM1]

Now I've tested the functionality and there's something that either I don't understand, or that doesn't work:
I had 2 browser saved, I downloaded the backup phrases, and deleted the browser shares:

1. If I refresh, I'm still logged-in automatically -> from my understanding this shouldn't be possible
2. If I manually log-out, then try to login and chose to use a backup phrase, both backup phrases that I just downloaded don't work.
3. I login with the password then, that works, I'm not asked to save the browser, and I end up with the same settings as the screenshot above, refreshing logs me in automatically, so I think my browser definitely got saved.

Some of these are expected behaviour. I have numbered the items so it's easier to follow:

1. The auto-login is dependent on the serialized tkey store being in session storage. The final tkey private key is available there, so the device shares, and their presence/absence is irrelevant.

2. The device share was deleted, so even though you have one of the co-ords for the second point, share reconstruction requires both the x and y co-ords for 2 points. When a share is deleted, the y co-ord for that point is deleted from the metadata rendering that share useless in reconstructing the key.

3. Refreshing works whether the device is saved or not. Saving device is only used during key reconstruction, which session restoration with no session storage. My guess is that the browser is actually not saved, and if you start a new session you will be required to enter a password again. It seems that under certain circumstances the isNewDevice flag is not being set correctly, resulting in a successful login, but no ability to save the device.

Logging an issue to investigate 3 but do not feel that this edge case has anything to do with the PR at hand

[Tbaut]

Understood for the 1 thanks, didn't think about the session storage.
For 2 I think it might be a mistake to let users download these backup phrases without further information, because they are not real backup phrases like the others, they are half of one iiuc?. There's this "if" that we never mention anywhere which is "if you didn't delete the browser share linked to the mnemonic, then it'll work".

[FSM1]

Understood for the 1 thanks, didn't think about the session storage.
For 2 I think it might be a mistake to let users download these backup phrases without further information, because they are not real backup phrases like the others, they are half of one iiuc?. There's this "if" that we never mention anywhere which is "if you didn't delete the browser share linked to the mnemonic, then it'll work".

Hmm, I think adding more explanation and text to the app will only confuse people more to be honest.

To me it feels quite natural that a mnemonic that is linked to a device share would not work if the device share is deleted, but maybe I am just too close to the mechanics of it...

[Tbaut]

The problem I think is to call everything a backup phrase, and have in the end different behaviors. Don't want to block this PR further, it's not directly related. I think if I got confused, others might be. Agree that too much text doesn't help. However, a popup to confirm the deletion of a browser could tell "Look any browser recovery mnemonic that was generated will not work any more".
I think this would be small enough for users to care reading. And if they don't.. then at least we tried.

[tanmoyAtb]

I agree, that a user will keep a mnemonic stored somewhere and expect it to work even if he deletes something! at lease that was my first impulse.

[Tbaut]

Working well and looking good 🎉