Bug 24672 – ASSERTION FAILURE: !m_purgeableData in WebCore::CachedResource::data() saving a WebArchive

• Status: RESOLVED
• Resolution: FIXED
• Component: WebCore Misc.

[David Kilzer (:ddkilzer)]

* SUMMARY
When saving a WebArchive of some pages with a Debug build of WebKit, an assertion failure occurs.  Noted in Bug 22931 Comment #4.

* STEPS TO REPRODUCE
1. Launch Debug build of WebKit.
2. Open URL:  <http://www.mingpaonews.com/20090318/gba1.htm>
3. Save As...WebArchive.

* RESULTS
Crash due to assertion failure.

* REGRESSION
This is a regression from builds of WebKit before the cache was purgeable.

* NOTES
Console output of crash:

ERROR: Failed to archive subresource for http://www.mingpaonews.com/image/jflow_normal.gif
(/Volumes/Data/WebKit.git/WebCore/loader/archive/cf/LegacyWebArchive.cpp:545 static WTF::PassRefPtr<WebCore::LegacyWebArchive> WebCore::LegacyWebArchive::create(const WebCore::String&, WebCore::Frame*, WTF::Vector<WebCore::Node*, 0ul>&))
ERROR: Failed to archive subresource for http://www.mingpaonews.com/image/jflow_selected.gif
(/Volumes/Data/WebKit.git/WebCore/loader/archive/cf/LegacyWebArchive.cpp:545 static WTF::PassRefPtr<WebCore::LegacyWebArchive> WebCore::LegacyWebArchive::create(const WebCore::String&, WebCore::Frame*, WTF::Vector<WebCore::Node*, 0ul>&))
ERROR: Failed to archive subresource for http://www.mingpaonews.com/image/jflow_multibox_bkg_460.jpg
(/Volumes/Data/WebKit.git/WebCore/loader/archive/cf/LegacyWebArchive.cpp:545 static WTF::PassRefPtr<WebCore::LegacyWebArchive> WebCore::LegacyWebArchive::create(const WebCore::String&, WebCore::Frame*, WTF::Vector<WebCore::Node*, 0ul>&))
ASSERTION FAILED: !m_purgeableData
(/Volumes/Data/WebKit.git/WebCore/loader/CachedResource.h:137 WebCore::SharedBuffer* WebCore::CachedResource::data() const)

[David Kilzer (:ddkilzer)]

<rdar://problem/6574263>

[Cameron Zwarich (cpst)]

I know how to fix this.

[Cameron Zwarich (cpst)]

The fix should really be doing something along these lines, except for WebCore::LegacyWebArchive::create():

http://trac.webkit.org/changeset/39517

Unfortunately, this can't just be done where cachedResource->data() is used, because an earlier call to DocumentLoader::subresource() also uses the cached resource's data. The right thing to do is probably to make DocumentLoader::subResource() do something along the lines of r39517, but I wanted to ask somebody who knows the code.

I'll unassign this in case someone else wants to take a stab at it.

[Darin Adler]

Created attachment 29051 [details]
patch

[Darin Adler]

http://trac.webkit.org/changeset/42095

[David Kilzer (:ddkilzer)]

Comment on attachment 29051 [details]
patch

>+        I couldn't create a test case for this. In fact, the case in the bug doesn't exist any more,
>+        but there is an Apple-internal website I was able to use to reproduce and fix.

Any news story on the mingpaonews.com site reproduces this issue.