Caching bug with showMethods?

showMethods isn't reporting inherited methods when it is first
called.  The methods are there and after calling them, showMethods
gives the right output.

Here is an example (using R-devel r39647):

setClass("A", representation(x="numeric"),
         prototype=list(x=1))

setClass("B", contains="A",
         prototype=list(x=2))

setMethod("initialize", "A",
          function(.Object) {
              cat("In A's init\n")
              .Object at x <- .Object at x + 1
              .Object
          })

setMethod("show", "A",
          function(object) cat("An A like thing. x =", object at x, "\n"))

showMethods(classes="B")  ## should give output, but doesn't
showMethods(classes="A")

aa <- new("A")
bb <- new("B")

aa
bb

## Now it will give output
showMethods(classes="B")




--
+ seth

No, not a bug.

Inherited methods are never cached until they are needed, for rather
obvious efficiency reasons. See ?showMethods, under argument
inherited=

If what you were trying to do was find out what method would be called
for class "B" without calling it, use selectMethod().

If showMethods() were extended in this way but consistent with its
behavior now, you would potentially get a mess (and do a lot of
computation).  Any method with "ANY" in any element of its signature
qualifies (in particular, all default methods).  And if you said
inherited=TRUE, but did NOT give a limiting class---!

I think the definition you want is to find all methods for which one
of the superclasses of "B" appears explicitly in a signature, but
excluding "ANY" from the superclasses used.  That's quite a different
(and longer) calculation than showMethods() does, but could indeed be
useful.