Why do "Joining, by =" messages bleed through in Rmarkdown code blocks despite using warning=FALSE? Should I report as a bug?

Question

A helpful sequence here (suppress comment "joining by..." when running dplyr::left_join) shows that you can suppress the message by explicitly stipulating the joining variable or by wrapping the whole dplyr block in suppressWarnings to get rid of this bleed through.

This is useful but I don't understand why neither "message=FALSE" nor "warning=FALSE" in an Rmarkdown code block header suppresses this message? The message seems somewhere between a message and a warning to judge by comments on it elsewhere but I would have thought we should be able to suppress the message with one of those block options.

I do understand the logic behind having the message when "by = " is not specified and I do know about suppressWarnings but wrapping dplyr blocks in anything seems a poor fit with the useful tidyverse syntax.

Is this worth a bug report or feature request? And if so, to whom: is the issue with how dplyr emits the message or with knit or somewhere else?

Answer 1

For me, the best option is to set your by argument explicitly:

tib1 %>% 
    left_join(tib2, by = "lwr") %>%
    pander()

Alternately, use suppessMesseages:

suppressMessages(tib1 %>%
                   left_join(tib2) %>%
                   pander())