for param in request.REQUEST fails with (a misleading) KeyError exception

[Tamas Szabo]

If you do a "for param in" on request.POST or request.GET it works as expected, but if you do it on request.REQUEST it fails.

The following simple code

for param in request.REQUEST:
    print param

will throw a KeyError exception! A few WTFs later I realized that the problem is in django.util.datastructures.MergeDict, that doesn't implement iter, but it does implement getitem so the for calls into getitem and passes in 0 (index of first element in a sequence).
0 won't be a valid key in request.GET or request.POST so a KeyError is thrown by the MergeDict.getitem implementation.

I've attached a patch that adds the missing iter method.

[anonymous]

I get a test failure when applying this patch: "AttributeError: type object 'itertools.chain' has no attribute 'from_iterable'". Using python 2.5.4.

[gisle]

Updated patch that also fixes MergeDict.items()

[gisle]

Revised patch based on IRC feedback from Alex_Gaynor (provides iter{iterms,keys,values}) and use tuple unpacking instead of indexing)

[jkocherhans]

(In [12498]) Fixed #12820. Implemented other dict methods for MergeDict. Thanks, Gisle Aas.

[jkocherhans]

(In [12501]) [1.1.X] Fixed #12820. Implemented other dict methods for MergeDict. Backport of [12498] from trunk.

[Jacob]

Milestone 1.2 deleted