anova.mlm for single model (one-way repeated measured anova)

Dear list members:

I'd like to one-way repeated measured anova by using mlm.
I'm using R-2.3.1 and my code is:

dat<-matrix( c(9,7,8,8,12,11,8,13,     6,5,6,3,6,7,10,9,
               10,13,8,13,12,14,14,16, 9,11,13,14,16,12,15,14),
            ncol=4, dimname=list(s=1:8, c=1:4))
mlmfit<-lm(dat~1)
anova(mlmfit, X=~1)
Error: ceiling(length.out) : Non-numeric argument to mathematical function

this error occurs in anova.mlm

        if (rk > 0) {
            p1 <- 1:rk
            comp <- object$effects[p1, ]
            asgn <- object$assign[object$qr$pivot][p1]
            nmeffects <- c("(Intercept)", attr(object$terms,
                "term.labels"))
            tlabels <- nmeffects[1 + unique(asgn)]
             ix <- split(seq(length = nrow(comp)), asgn)  #HERE
            ss <- lapply(ix, function(i) crossprod(comp[i, ,
                drop = FALSE]))
            df <- sapply(split(asgn, asgn), length)
        }

because nrow(comp) returns NULL.

in my memory, R-2.2.* ( or may be R-2.3.0) can correctly handle this code.
so, I think this is a kind of side-effect of fixing PR#8679.

currently, i can workaround as follows:

anova(mlmfit, update(mlmfit, ~0), X=~1)

this code returns correct answer.


I don't know whether this behavior is correct or bug.