Bug 20854 - appcache : fallback entries need clarification on duplicates
Summary: appcache : fallback entries need clarification on duplicates
Alias: None
Product: HTML WG
Classification: Unclassified
Component: HTML5 spec (show other bugs)
Version: unspecified
Hardware: PC All
: P2 normal
Target Milestone: ---
Assignee: Robin Berjon
QA Contact: HTML WG Bugzilla archive list
Keywords: CR
Depends on:
Reported: 2013-02-02 11:12 UTC by Laurent Perez
Modified: 2013-04-24 16:29 UTC (History)
6 users (show)

See Also:


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Description Laurent Perez 2013-02-02 11:12:38 UTC

The reference http://www.w3.org/html/wg/drafts/html/master/browsers.html#concept-appcache-fallback needs to mention that fallback entries can't contain uri duplicates.

Use case : on first manifest visit, cookieless user agent may use url rewriting for resources, ie use a ";jsessionid=" trail or some other kind of session parameter. The uri + session trail seems to be the cache key at least on iOS devices.

The following manifest will cause Chrome 24 to fail loading the manifest, with a cryptic "Application Cache Error event: Failed to commit new cache to storage" error message : 


/ /fallback.php
/ /fallback.php?sessionid=1234


This will fail because of the duplicate /fallback.php line. Removing the second one with ?sessionid fixes the problem. I believe Chrome does not know which fallback line to use.

Comment 1 Ian 'Hixie' Hickson 2013-02-06 21:43:58 UTC
That's just a bug in chrome. The spec allows "nested" fallback entries like this.
Comment 2 Robin Berjon 2013-04-24 16:29:11 UTC
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Status: Rejected
Change Description: none
Rationale: A duplicate fallback namespace is just ignored as per spec, this is just an implementation error.