firstof template tag doesn't accept strings with spaces

[Wesley Fok <portland@…>]

When firstof is passed a quoted string with a space, ex. {% firstof var1 var2 var3 "fallback string" %}, it splits the string and reads the pieces as False. If the string is the last element in the firstof tag, then the whole thing returns False and firstof returns a blank string.

[Wesley Fok <portland@…>]

Simple patch for firstof compilation function.

[Michael Axiak <axiak@…>]

This seems like an obvious bug and fix.
I hope someone with more clout can verify this.

[mboersma]

The docs for the firstof tag make no mention of accepting literal strings, only variables. So my first inclination was "wontfix."

On the other hand, similar tags like "if" seem to handle literal strings as if they were (always True) variables. And token.split_contents is a more reliable method that is used elsewhere and arguably should be here too. Finally, having a "fallback string" as described here seems quite useful, although if we went that we it implies a documentation change.

I'll be glad to make the doc changes if a core developer decides this is worth doing, otherwise we should close it as wontfix.

[mboersma]

Patch with docs and tests for handling strings with spaces in the firstof tag.

[mtredinnick]

(In [6571]) Fixed #4123 -- Changed the firstof template tag to correctly handle a literal
string as its last argument. Thanks, Wesley Fok and Matt Boersma.