300983 - RSS Reader unable to parse feeds which contain xmlns parameters pointing to missing files

Status: RESOLVED FIXED

(MailNews Core :: Feed Reader, defect)

Description

[Jay Rossiter]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.9) Gecko/20050711 Firefox/1.0.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.9) Gecko/20050711 Firefox/1.0.5

The XML namespaces spec declares that namespaces need not be tied to the ability
to retrieve any schema "(even if one exists)".  As such, the xmlns attribute is
not required to point to a file that actually contains schema information, or
even exists at all.

Thunderbird will refuse to parse any RSS file which contains an xmlns attribute
that points to a page that returns a 404 error.

If the page exists in any fashion (doesn't return an HTTP error), Thunderbird
has no problems with the RSS page.

Reproducible: Always

Steps to Reproduce:
1. Validate referenced feed -
http://www.feedvalidator.org/check.cgi?url=http%3A%2F%2Fwww.cothlamadh.net%2F%7Esigne%2Fbugs%2Fthunderbird%2Fxmlnsbug.xml

2. Attempt to add referenced feed as an RSS subscription in Thunderbird

3. Dialog appears stating "[...] is not a valid RSS feed."

Actual Results:  
Feed is rejected as invalid.

Expected Results:  
The xmlns field does not need to be validated or retrieved for a feed to be valid.

Comment 1

[Jay Rossiter]

Forgot to include link to XML namespaces spec:

http://www.w3.org/TR/1998/PR-xml-names-19981117#ns-decl

Comment 2

[Magnus Melin [:mkmelin]]

Confirming with 20050715/linux. However, the symptoms are a little bit different
on trunk. On trunk, the test URL remains at "Verifying the feed..."

In the JavaScript console you get this error:

Error: [Exception... "Component returned failure code: 0x80004003
(NS_ERROR_INVALID_POINTER) [nsIRDFService.GetLiteral]"  nsresult: "0x80004003
(NS_ERROR_INVALID_POINTER)"  location: "JS frame ::
chrome://messenger-newsblog/content/Feed.js :: anonymous :: line 281"  data: no]
Source File: chrome://messenger-newsblog/content/Feed.js
Line: 281

Comment 3

[Mike Cowperthwaite]

(In reply to comment #2)
> Confirming with 20050715/linux. However, the symptoms are a little bit
> different on trunk. On trunk, the test URL remains at "Verifying the feed..."
> 
> In the JavaScript console you get this error:

I'm not seeing that with either 1.5a1-0904 or 1.6a1-0904, Win2K.  I get the 
results as stated in the original report, plus I see this in the JavaScript 
Console:
> Error: no element found
> Source File: http://www.cothlamadh.net/~signe/bugs/thunderbird/xmlnsbug.xml
> Line: 1, Column: 1


HOWEVER: The feed validator, referenced in the original report, ALSO says this 
is not a valid feed:
> Sorry   This feed does not validate.
> 
> line 1, column 0: XML parsing error: <unknown>:1:0: no element found

Jay Rossiter, please report back once the validator approves of that feed.

Comment 4

[Jay Rossiter]

The file had been removed during system troubles.  I've replaced it with a file
that validates and displays the error.  (In 1.0.6)

Comment 5

[Mike Cowperthwaite]

OK; now I'm seeing the same results as reported in comment 2, with 1.5a1 
and 1.6a1.

Comment 6

[Robert Sayre]

Attachment: RSS 0.9/2.0 parser needs to look for elements in a namespace-aware manner

Patched against trunk.

Comment 7

[Robert Sayre]

Attachment: fix a typo in on of the method calls

Comment 8

[Scott MacGregor]

fixed branch and trunk.

Comment 9

[Scott MacGregor]

Comment on attachment 196560 [details] [diff] [review]
fix a typo in on of the method calls

I forgot to plus this when I checked it in.