last_warnings() and last_messages() return a list of all
warnings and messages that occurred during the last R command.
global_entrace() must be active in order to log the messages and
warnings.
By default the warnings and messages are printed with a simplified
backtrace, like last_error(). Use summary() to print the
conditions with a full backtrace.
last_warnings(n = NULL)last_messages(n = NULL)
How many warnings or messages to display. Defaults to all.
Enable backtrace capture with global_entrace():
global_entrace()
Signal some warnings in nested functions. The warnings inform about which function emitted a warning but they don't provide information about the call stack:
f <- function() { warning("foo"); g() }
g <- function() { warning("bar", immediate. = TRUE); h() }
h <- function() warning("baz")f()
#> Warning in g() : bar
#> Warning messages:
#> 1: In f() : foo
#> 2: In h() : baz
Call last_warnings() to see backtraces for each of these warnings:
last_warnings() #> [[1]] #> <warning/rlang_warning> #> Warning in `f()`: foo #> Backtrace: #> 1. global f() #> #> [[2]] #> <warning/rlang_warning> #> Warning in `g()`: bar #> Backtrace: #> 1. global f() #> 2. global g() #> #> [[3]] #> <warning/rlang_warning> #> Warning in `h()`: baz #> Backtrace: #> 1. global f() #> 2. global g() #> 3. global h()
To get a full backtrace, use summary(). In this case the full
backtraces do not include more information:
summary(last_warnings()) #> [[1]] #> <warning/rlang_warning> #> Warning in `f()`: #> foo #> Backtrace: #> x #> 1. \-global f() #> #> [[2]] #> <warning/rlang_warning> #> Warning in `g()`: #> bar #> Backtrace: #> x #> 1. \-global f() #> 2. \-global g() #> #> [[3]] #> <warning/rlang_warning> #> Warning in `h()`: #> baz #> Backtrace: #> x #> 1. \-global f() #> 2. \-global g() #> 3. \-global h()