Bug when hovering variables

[xiajunwen1007]

Describe the bug
When hover on a variable defined before, it shows the definition of the variable. But in some cases, definition isn't correct. For example, paste the following code in the vscode.

for (ll in 1:3){
 p = ll
 I = array(0:0, dim=c(p,p))
}

Then hover on the variable p. The correct behavior should be popping up a panel showing p=ll, but it shows for (ll in 1:3){. A screenshot is below.

[renkun-ken]

Thanks for reporting! I could reproduce it. It is a bug in the hover provider in languageserver. So I transfer this issue there.

[renkun-ken]

If the code is modified as below with <- as assignment, then the hover of p works as expected.

for (ll in 1:3){
 p <- ll
 I = array(0:0, dim=c(p,p))
}

But = does not work correctly in this case. Let me take a closer look at this.

[renkun-ken]

The following case works as expected.

local({
  for (ll in 1:3) {
    p1 = ll
    I = array(0:0, dim = c(p1, p1))
  }
})

Then is must be caused by the competing workspace and scope definitions. In this case, the scope definition takes priority over the workspace definition (which has less accurate location, i.e. only top-level expressions), but vice verse in the first example.

[renkun-ken]

In this example, p does not work while p1 works.

for (ll in 1:3) {
  p = ll
  p1 = ll
  I = array(0:0, dim = c(p, p1))
}

[renkun-ken]

If you move your cursor on the right side of p, then it works too.

Not sure why hovering on the left half of p shows the for (ll in 1:3) {.

[xiajunwen1007]

If the code is modified as below with <- as assignment, then the hover of p works as expected.

<- doesn't work as well. In my computer, the behavior of <- is the same as =. When I first hover on the left half of the p variable in the c(p,p), it shows correct definition. Things go wrong after first hovering. It is weird.

[renkun-ken]

Should be fixed via #464. Would you like you try and see if it works for you?

[xiajunwen1007]

Yes, it's my pleasure. But I'm a green hand in git, so I would try this after it is merged. Thank you very much.

[renkun-ken]

You could use the following to try:

remotes::install_github("REditorSupport/languageserver#464")

[xiajunwen1007]

Thank you very much. I have tried this, but it seems there are still some problems. Maybe I configure something wrong. I posted a screenshot blew.

The behavior is more like this that sometimes it will pop up definition, and sometimes not.

[renkun-ken]

The hover extracts the word when you move your cursor on the right part of the word. The help links are generated by vscode-R which uses the editor api to get the word under cursor. They are two different sources of hover information.

[xiajunwen1007]

Thank you very much. Now everything works fine. I also found the format would affect the hovering behavior. For example, I extract a part of my teacher's code. The format is ugly.

for (l in 1:rep){
b1=array(0:0,dim=c(p,K))
index1 = sample(rep(1:p))[1:sp]

for (d in 1:K){
	for (i in index1){b1[i,d]=(1+runif(1))*sqrt(log(p)/n1)*sample(c(1,-1),1)}
}

Things go wrong when I hover on index1.

It works when the format is good though the code is the same.

for (l in 1:rep) {
 b1 <- array(0:0, dim = c(p, K))
 index1 <- sample(rep(1:p))[1:sp]

 for (d in 1:K) {
  for (i in index1) {
   b1[i, d] <- (1 + runif(1)) * sqrt(log(p) / n1) * sample(c(1, -1), 1)
  }
 }
}

Nonetheless, it's enough for me. Thank you very much.