232223 - encodeURIComponent() may result in garbage

Status: RESOLVED DUPLICATE of bug 314456

(Core :: JavaScript Engine, defect)

Description

[Pierre Chanial]

that's a followup from bug 228103.
The problem is not that trivial, there's some funkiness around.
I ran some systematic tests and I'll synthesize them here:

1) EncodeURIComponents("") seems to return the empty string (typeof: string,
length: 0, dump:nothing) but when it is passed in
(mozilla/browser/base/content/search.xml):
searchURL = ISEARCHSVC.GetInternetSearchURL(this.currentEngine,
              encodeURIComponent(""), 0, 0, {value:0});
then searchURL contains garbage characters.

whereas: s/encodeURIComponent("")/"" does not !

2) I was surprized that encodeURIComponent(null) returns the "null" string
instead of the empty string or null.
But that's apparently following the spec Ecma-262 15.1.3.4 which makes a call to
ToString.

3) but then the cases:
given var a,b={}; a=null; b.value=null; this.value=null;
 - s/encodeURIComponent("")/encodeURIComponent(null)
 - s/encodeURIComponent("")/encodeURIComponent(a)
 - s/encodeURIComponent("")/encodeURIComponent(b.value)
will return a query with "null" as per 2
but the case:
 - s/encodeURIComponent("")/encodeURIComponent(this.value)
will result in garbage...

Comment 1

[Phil Schwartau]

cc'ing Brendan for his advice. Note this is a follow-up to bug 228103.

To summarize: in the file mozilla/browser/base/content/search.xml,
the following two calls should be equivalent:

ISEARCHSVC.GetInternetSearchURL(...,  encodeURIComponent(""),  ...)
ISEARCHSVC.GetInternetSearchURL(...,          "",              ...)

Yet the first outputs garbage characters, whereas the second does not.
Also note the reporter's interesting variation in 3) above using |null|.


Note how |ISEARCHSVC| is defined earlier in the file:

var ISEARCHSVC =
Components.classes["@mozilla.org/rdf/datasource;1?name=internetsearch"]
                 .getService(Components.interfaces.nsIInternetSearchService);


Is it possible that the bug might be caused by this component
and its |GetInternetSearchURL()| method, rather than by any bug
in the JS method |encodeURIComponent()|?

As the reporter notes, |encodeURIComponent("")| returns the empty string
every time we try it independently. I have also tried incorporating it 
into JS functions, and continue to get the empty string as expected.
For example, I ran this script successfully in the current JS shell:


function F(obj1, str, int1, int2, obj2)
{
  var ret = '';

  ret += 'The return value is: "';
  ret += str;
  ret += '"\nlength = ';
  ret += str.length;

  return ret;
}

var ISEARCHSVC = {};
ISEARCHSVC.GetInternetSearchURL = F;

var searchURL = ISEARCHSVC.GetInternetSearchURL({},
                                                encodeURIComponent(""), 
                                                0, 0, {value:0}
                                                );
print(searchURL);

Comment 2

[Bob Clary [:bc] (inactive)]

-> default qa

Comment 3

[Boris Zbarsky [:bzbarsky]]

Is this still a problem?  If so, this should probably block the next set of security releases....

Comment 4

[:Gavin Sharp [email: [e-mail]]]

(In reply to comment #1)
> Is it possible that the bug might be caused by this component
> and its |GetInternetSearchURL()| method, rather than by any bug
> in the JS method |encodeURIComponent()|?

Not only possible, I'd say it's highly likely.

Comment 5

[Blake Kaplan (:mrbkap) (inactive)]

This looks a lot like bug 314456 which added empty string protection to the encodeURI* and decodeURI* functions. Marking the duplicateness.

*** This bug has been marked as a duplicate of 314456 ***