show messages, warnings and errors in knit()

[yihui]

otherwise users may never realize them

[matthias-studer]

Hello,

I have tried to use the following code to "compile" a file using knitr. However, if I do it, then all header definition (in LaTeX) are not included in the resulting file.

require(knitr)
filename <- "test2.Rnw"

## Setting error and warning hooks
knit_hooks$set(error=
local({
    error_list <- list()
    error_counter <- 0
    function(x, options){
        error_list[[options$label]] <<- c(error_list[[options$label]], x)
        error_counter <<- error_counter +1
    }
}))

knit_hooks$set(warning=local({
    warning_list <- list()
    warning_counter <- 0
    function(x, options){
        warning_list[[options$label]] <<- c(warning_list[[options$label]], x)
        warning_counter <<- warning_counter +1
    }
}))

## Knitting file
res <- tryCatch({
    knit(filename)
    NULL
}, error=function(e) e)

## Getting number of R errors
error_count <- environment(knit_hooks$get("error"))$error_counter

if(is.null(res) && error_count <1) { ## No error by knitr
    cat(filename, " success\n\n", file=stdout())
}else if(error_count >0){
    error_list <- environment(knit_hooks$get("error"))$error_list
    for(n in names(error_list)){
        cat("Error(s) in chunk: " , n, "\n", file=stderr())
        for(e in error_list[[n]]){
            cat("\t", e,"\n", file=stderr())
        }
        cat("\n", file=stderr())
    }
} else{ ## Error in knitr
    cat("\n\nknitr error: ", as.character(res), "\n\n", file=stderr())
}

[github-actions]

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