[Feature]: Allow launching in incognito mode

[stevenwdv]

Currently, puppeteer.launch opens a non-incognito context, and while one can open an incognito context via createIncognitoBrowserContext, this seems like an unnecessary hassle, especially since an extra context was created (and remains open).
Chromium supports launching in incognito mode via -incognito, but specifying this in puppeteer.launch let's Puppeteer still think that it's a non-incognito context: isIncognito returns false, which may cause some problems.

It would be nice to have a documented way of doing this, via a boolean option in puppeter.launch.

[jrandolf]

This sounds very reasonable. I suppose we can add a small check that sees if the launch arguments contains incognito and flips the flag appropriately. Would that suffice?

[stevenwdv]

I don't know the ins and outs, but if that's all it takes to properly set up an incognito session, you could do that. Although I think having a boolean would be a nicer way, and this could also be made compatible with Firefox (disclaimer: I haven't used puppeteer with FF so idk if you'd also use launch for that).

[jrandolf]

Hmm, now that I think about it, it would still only be a heuristic since someone could use a custom-chrome binary which defaults to incognito (as if someone would do that). I'll take a look at Firefox and come up with some solutions.

[OrKoN]

I think it's actually a bug in Puppeteer which assumes that the default browser context is non-incognito. It should probably derive it from the actual running browser context. The entire isIncognito check in Puppeteer does not look very robust.

[stevenwdv]

@OrKoN Don't you mean "assumes that the default browser context is *non-*incognito" ?

[jacty]

Maybe we can prioritize the context created by user instead of using the default one? When user specified, no default one will be created?

[OrKoN]

the default one is created by the browser itself and it is not explicitly created by Puppeteer.

[OrKoN]

Closing in favor of #11686 We want to get rid of relying on the term "incognito" as it is Chrome-specific and instead we will only report if a given context is the default one or if it was created via Puppeteer's https://pptr.dev/api/puppeteer.browser.createbrowsercontext/ (where the word incognito has already been dropped).