VSCode and ggplot (randomly) throw error "Error in UseMethod("depth")".

[strengejacke]

I recently had some issues with ggplot and vscode. I couldn't create a reprex to reproduce this bug, maybe it's only interactive?

This is the error I get:

Error in UseMethod("depth") : 
  no applicable method for 'depth' applied to an object of class "NULL"

Here's one example:

Traceback:

> traceback()
7: depth(path)
6: upViewport(depth(vp), recording = FALSE)
5: popgrobvp.viewport(x$vp)
4: popgrobvp(x$vp)
3: postDraw.grob(x)
2: postDraw(x)
1: drawGTree(x)

And here's another example:

> library(ggplot2)
Use suppressPackageStartupMessages() to eliminate package startup
messages
> data(iris)
> library(ggplot2)
> data(iris)
> ggplot(iris, aes(x = Sepal.Length, y = Sepal.Width, color = Species)) +
+   geom_point()
> Error in UseMethod("depth") : 
  no applicable method for 'depth' applied to an object of class "NULL"

> traceback()
21: depth(path)
20: upViewport(depth(vp), recording = FALSE)
19: popgrobvp.viewport(x$vp)
18: popgrobvp(x$vp)
17: postDraw.grob(x)
16: postDraw(x)
15: drawGTree(x)
14: recordGraphics(drawGTree(x), list(x = x), getNamespace("grid"))
13: grid.draw.gTree(x$children[[i]], recording = FALSE)
12: grid.draw(x$children[[i]], recording = FALSE)
11: drawGTree(x)
10: recordGraphics(drawGTree(x), list(x = x), getNamespace("grid"))
9: grid.draw.gTree(x$children[[i]], recording = FALSE)
8: NextMethod()
7: grid.draw.absoluteGrob(x$children[[i]], recording = FALSE)
6: grid.draw(x$children[[i]], recording = FALSE)
5: drawGTree(x)
4: recordGraphics(drawGTree(x), list(x = x), getNamespace("grid"))
3: grid.draw.gTree(x$children[[i]], recording = FALSE)
2: grid.draw(x$children[[i]], recording = FALSE)
1: drawGTree(x)

Sometimes, it happens almost immediately, sometimes first after many tries. I'm using vscode 1.88.1, R 4.3.3, Windows 11, all R packages up to date (and also all VScode extensions).

When I once get this issue, it appears each time for ggplot-plots - but not, if I try to create a reprex. The reprex is displayed in the "viewer" tab, while plots are shown in the "plots" tab. I guess it could be an interactive-issue.

[teunbrand]

Thanks for the report! I'm not too familiar with how VSCode displays plots; do you have any idea what graphics device is used to display plots interactively?

[strengejacke]

I'm not very familiar with the technical background, either. I know that you can use the httpgd-package to display plots in R (see also https://nx10.github.io/httpgd/articles/b01_vscode.html), and that's what I have installed, too.

[thomasp85]

This remains a grid bug, not a ggplot2 bug. Sadly it has proven quite elusive to figure out why it happens but it has to do with some invalidation of the plot state in interactive devices

[strengejacke]

Ok. I was just curious because I realized this error just recently, after the ggplot 3.5.0 release. This could be a coincidence, but my guess was some kind of interaction between grid and the latest ggplot might lead to this issue.

[strengejacke]

It only seems to occur when the plot-window is not yet created. Once we have the plot-pane open, this error doesn't seem to re-appear.

[strengejacke]

Here's a short video, not sure if this helps. But maybe this issue should be closed/transferred anyway?

https://github.com/tidyverse/ggplot2/assets/26301769/56087cd1-e8af-42f5-bc21-63924c5d299b

[thomasp85]

Thanks - I am going to close it since it is not something on the ggplot2 side. I know @pmur002 is aware of the issue so maybe this will eventually get fixed.

There can be many reasons why it started appearing with the latest release of ggplot2. I think the output from ggplot is by far the most complex grobs that gets rendered in R so it is a great stress-test of grid. Small changes may stress grid in new ways, even if ggplot2 is not doing anything wrong