746324 - Cache behaviour, back key and bad networks

Status: RESOLVED INCOMPLETE

(Firefox for Android Graveyard :: General, defect)

Description

[Spider]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20100101 Firefox/11.0
Build ID: 20120313130407

Steps to reproduce:

Surfing with Fennec (14, nightly)  over 3G while on a train (spotty connection ) shows some interesting behaviour in caching.

Browsing site A, clicking link to site B, then onwards to C, and then D; At D the network is timing out due to radio shadow, and you get an error.

Pressing the _back_ key in this situation, will in most (all?) cases cause an attempt to reconnect/revalidate the connection that it knows is already broken. Repeating this backwards down the chain only reinforces the behaviour.



Other scenarios that also cause interesting issues are as follows:
Many tabs,  some with history in it, Switching the application out, then back, and changing tab to one that had been inactive for a while, and it will attempt to revalidate the page against the (failed) network. Instead of failing gracefully and displaying the old content, the user ends up with no content at all.

There are also some entertaining issuethere's also some entertaining differences in a situation 
Load site A, press link B, Press link C,  Inject network fault( flight mode) , press Back, (works) press back (works) press link B again => Failure.





Actual results:

In most cases, a page that was just loaded and displaying a moment ago, is no longer available for reading or browsing. Basically turning the page into a complete fault, even if nothing had changed, simply because the network connection dropped out.


Expected results:

In situations like mobile, where network dropouts (temporary such at least) are very common, the users expect their browser to be protective of them, and not ruin the experience completely.
It's better to fail, and fall back gracefully to the previously cached, stale object, than to show nothing at all, or an unfriendly dialogue.


It should be noticed here that the behaviour of various popular mobile browsers have different behaviours:

Android stock browser ( Caches aggressively )
Google Chrome (Android)
Opera Mobile
Opera Mini
Nightly

Shortly : on mobile, users have an expectation that network is flaky, and will appreciate attempts to not break things due to this.

Comment 1

[Spider]

Further testing shows different behaviours between "Network failure: timeout" and "airplane mode", which means that my tests with airplane mode may not be very telling.

Comment 2

[Geoff Brown [:gbrown]]

Spider -- Would you mind giving a specific example? What are the urls for A, B, C, and D?

Comment 3

[Naoki Hirata :nhirata (please use needinfo instead of cc)]

Hi Spider, could you also give a logcat please?

Comment 4

[Aaron Train [:aaronmt]]

Need a follow-up for a log, or if this still reproduces on recent builds. Please re-open when information is provided.