r - 要求 R 调试器不要截断堆栈调用

Question

我想调试以下函数，但假设在调试器中查看 moreajaj 的参数等于什么(假设不像在这个人为的示例中那么明显)是有用的。我可以在调试器框架中打印它，但是在每个参数的每个框架中都这样做很烦人。在宣布每一帧时，如何才能使完整的参数调用在调试器中打印？

options(error = dump.frames)

#### suppose I do not see the function definitions, only see debugger below
some_function <- function(...) {
  stop('give error')
}

willGiveError <- function() {
  some_function(alongargument = "some long kind of default", anotherlongargument = "more long default something as example", moreajaj = "kdjflksdjf")
}

outerFunction <- function() willGiveError()

outerFunction()

# Error in some_function(alongargument = "some long kind of default", anotherlongargument = "more long default something as example",  : 
#   give error
> debugger()
# Message:  Error in some_function(alongargument = "some long kind of default", anotherlongargument = "more long default something as example",  : 
#   give error
# Available environments had calls:
# 1: outerFunction()
# 2: #1: willGiveError()
# 3: #2: some_function(alongargument = "some long kind of default", another
# 4: #2: stop("give error")
# 
# Enter an environment number, or 0 to exit  Selection: 

正如您在上面的调试器输出中看到的那样，它在第 2 帧中的“another”之后被剪切，我想在此处看到 anotherlongargument = "more long default something as example", moreajaj = "kdjflksdjf")

Answer 1

在 dump.frames() 的评估过程中，这些调用的文本表示被截断了。通过调用 limitedLabels() .

一个简单的解决方案是编写一个类似的函数，不同之处仅在于提供(足够大的值)maxwidth=论据 limitedLabels() .

## Identical to dump.frames _except_ for addition of maxwidth=10000 argument
my.dump.frames <- 
function (dumpto = "last.dump", to.file = FALSE) 
{
    calls <- sys.calls()
    last.dump <- sys.frames()
    names(last.dump) <- limitedLabels(calls, maxwidth=10000)  # <-- edited line
    last.dump <- last.dump[-length(last.dump)]
    attr(last.dump, "error.message") <- geterrmessage()
    class(last.dump) <- "dump.frames"
    if (dumpto != "last.dump") 
        assign(dumpto, last.dump)
    if (to.file) 
        save(list = dumpto, file = paste(dumpto, "rda", sep = "."))
    else assign(dumpto, last.dump, envir = .GlobalEnv)
    invisible()
}

然后设置它，而不是 dump.frames ，作为当错误中断 R 的评估时要运行的函数。

options(error=my.dump.frames)

有了这个设置，运行你提供的代码，然后进入调试器，就会得到你希望的结果:

debugger()
# Message:  Error in some_function(alongargument = "some long kind of default", anotherlongargument = "more long default something as example",  : 
#   give error
# Available environments had calls:
# 1: outerFunction()
# 2: #1: willGiveError()
# 3: #2: some_function(alongargument = "some long kind of default", anotherlongargument = "more long default something as example", moreajaj = "kdjflksdjf")
# 4: #2: stop("give error")
# 
# Enter an environment number, or 0 to exit  Selection: