savePlot() no longer automatically adds an extension to the filename.

On 03/06/2008 2:35 PM, Mike Prager wrote:

"S Ellison" <S.Ellison at lgc.co.uk> wrote:

Plaintive squeak: Why the change?
Some OS's and desktops use the extension, so forgetting it causes
trouble. The new default filename keeps a filetype (as before) but  
the
user now has to type a filetype twice (once as the type, once as
extension) to get the same effect fo rtheir own filenames. And the
extension isn't then checked for consistency with valid file  
types, so
it can be mistyped and saved with no warning. Hard to see the  
advantage
of doing away with it...

Just for the record. . .
This change broke a *lot* of my code, including code used by
others.  Windows depends on file extensions.  Fortunately, fixes
using getRversion are not too difficult.

Then you'll be happy to hear that Steve put together a patch and  
it's already committed, so it should make it into 2.7.1.  The patch  
adds the extension if there's no dot in the name, leaves the  
filename as-is if it sees one.  So this should be compatible with  
the majority of uses, only messing up cases where people really  
don't want an extension (now they'll have to add a dot at the end of  
their filename), or where they want an automatic one, but have  
another dot in the name.

AFAICS the savePlot() behavior is now (as of r45830) inconsistent  
across platforms due to the patch (r458229). The inconsistency is IMHO  
a bad thing - you shouldn't expect the same function to behave  
differently across platforms.

I'd strongly recommend against this change for several reasons: it  
changes the behavior of the function between 2.7.0 and 2.7.1, so that  
now you have to special-case three different versions (pre 2.7.0,  
2.7.0 and 2.7.1), there is now no way to specify a file without a dot  
(which is quite common in non-Windows world) and the behavior is  
incompatible with other similar functions.

I think the change of behavior in 2.7.0 was deliberate and in favor of  
consistency, because a filename specification should not be randomly  
mangled by the function (I have made that mistake myself before, so I  
know the pitfalls ;)). Extension is part of the filename, it's not a  
separate concept (also note that ".foo" is a valid  filename that  
doesn't have an extension). The argument about typos is moot since you  
can always define functions like
saveFoo <- function(prefix) savePlot(filename = paste(prefix, "foo",  
sep="."), type="foo")
At any rate I don't see how this can realistically be part of 2.7.1  
since it's not a bugfix and it changes the meaning of a function  
parameter. (And I usually don't mind disguising small features as  
bugfixes ;P)

Whether the change in 2.7.0 could be done differently (e.g. using  
another parameter for a full file name) is a different story, but I  
suspect that it should have been discussed before the 2.7.0 release...

Cheers,
Simon