XLConnect 'envir' error

Question

I manage a number of Excel reports, and I use R to do the preprocessing and write the output report. It's great because all I have to do is run the R function and distribute the reports, and the rest of the report writing is inactive time. The reports need to be in Excel format because it is the easiest to disseminate and the audience is large and non-technical. Once the data is pre-processed, I do this very, very simply using XLConnect:

file.copy(from = template,
          to = newFileName)

writeWorksheetToFile(file = newFileName,
                     data = newData,
                     sheet = "Data",
                     clearSheets = T)

However, one of my reports began throwing this error when I attempted to write the new data:

Error in ls(envir = envir, all.names = private) : 
invalid 'envir' argument

Furthermore, before throwing the error, the function ties up R for 15 minutes. The normal writing time is less than 10 seconds. I must confess, I don't understand what this error even means, and it did not succumb to my usual debugging methods or to any other SO solution.

I've noticed that others have referred to rJava (reinstalling this package didn't work) and to a Java cache of log files (not sure where this would be located on Mac). I'm especially confused as the report ran with no problems just one day earlier using precisely the same process, AND my other reports using the exact same process still work just fine.

I didn't update Java or R or my OS, or debug/rewrite any of the R code. So, starting from the beginning - how can I investigate this 'envir' error? What would you do if you were in my shoes? I've been working on this for a couple days and I'm stumped.

I'm happy to provide extra information if it will provide better context for more discerning programmers than myself :)

Answer 1

Update: My previous answer (below) did not, in fact, fix this intermittent error (which as the OP points out is extremely difficult to unpick due to the Java dependency). Instead, I followed the advice given here and migrated from the XLConnect package to openxlsx , which sidesteps the problem entirely.

Previous answer: I've been frustrated by precisely this error for a while, including the apparent intermittency and the tying up of R for several minutes when writing a workbook.

I just realised what the problem was: the length of the name of an Excel worksheet appears to be limited to 31 characters, and my R code was generating worksheet names in excess of this limit.

Just to be clear, I'm referring to the names of the individual tabbed sheets within an Excel workbook, not the filename of the workbook itself.

Trimming each worksheet name to no more than 31 characters fixed this error for me.