cnd-abort.md
In rlang: Functions for Base Types and Core R and 'Tidyverse' Features

withCallingHandlers() wrappers don't throw off trace capture on rethrow

Code
  # `abort()` error
  print(err)
Output
  <error/rlang_error>
  Error in `wch()`:
  ! High-level message
  Caused by error in `low3()`:
  ! Low-level message
  ---
  Backtrace:
       x
    1. +-testthat::expect_error(high1())
    2. | \-testthat:::expect_condition_matching(...)
    3. |   \-testthat:::quasi_capture(...)
    4. |     +-testthat (local) .capture(...)
    5. |     | \-base::withCallingHandlers(...)
    6. |     \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    7. \-rlang (local) high1()
    8.   \-rlang (local) high2()
    9.     \-rlang (local) high3()
   10.       +-rlang (local) wch(low1(), error = function(err) handler1(err))
   11.       | \-base::withCallingHandlers(expr, ...)
   12.       \-rlang (local) low1()
   13.         \-rlang (local) low2()
   14.           \-rlang (local) low3()
Code
  summary(err)
Output
  <error/rlang_error>
  Error in `wch()`:
  ! High-level message
  Caused by error in `low3()`:
  ! Low-level message
  ---
  Backtrace:
       x
    1. +-testthat::expect_error(high1())
    2. | \-testthat:::expect_condition_matching(...)
    3. |   \-testthat:::quasi_capture(...)
    4. |     +-testthat (local) .capture(...)
    5. |     | \-base::withCallingHandlers(...)
    6. |     \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    7. \-rlang (local) high1()
    8.   \-rlang (local) high2()
    9.     \-rlang (local) high3()
   10.       +-rlang (local) wch(low1(), error = function(err) handler1(err))
   11.       | \-base::withCallingHandlers(expr, ...)
   12.       \-rlang (local) low1()
   13.         \-rlang (local) low2()
   14.           \-rlang (local) low3()

Code
  # C-level error
  print(err)
Output
  <error/rlang_error>
  Error in `wch()`:
  ! High-level message
  Caused by error:
  ! Low-level message
  ---
  Backtrace:
       x
    1. +-testthat::expect_error(high1())
    2. | \-testthat:::expect_condition_matching(...)
    3. |   \-testthat:::quasi_capture(...)
    4. |     +-testthat (local) .capture(...)
    5. |     | \-base::withCallingHandlers(...)
    6. |     \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    7. \-rlang (local) high1()
    8.   \-rlang (local) high2()
    9.     \-rlang (local) high3()
   10.       +-rlang (local) wch(low1(), error = function(err) handler1(err))
   11.       | \-base::withCallingHandlers(expr, ...)
   12.       \-rlang (local) low1()
   13.         \-rlang (local) low2()
   14.           \-rlang (local) low3()
   15.             \-rlang (local) fail(NULL, "Low-level message")
Code
  summary(err)
Output
  <error/rlang_error>
  Error in `wch()`:
  ! High-level message
  Caused by error:
  ! Low-level message
  ---
  Backtrace:
       x
    1. +-testthat::expect_error(high1())
    2. | \-testthat:::expect_condition_matching(...)
    3. |   \-testthat:::quasi_capture(...)
    4. |     +-testthat (local) .capture(...)
    5. |     | \-base::withCallingHandlers(...)
    6. |     \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    7. \-rlang (local) high1()
    8.   \-rlang (local) high2()
    9.     \-rlang (local) high3()
   10.       +-rlang (local) wch(low1(), error = function(err) handler1(err))
   11.       | \-base::withCallingHandlers(expr, ...)
   12.       \-rlang (local) low1()
   13.         \-rlang (local) low2()
   14.           \-rlang (local) low3()
   15.             \-rlang (local) fail(NULL, "Low-level message")

`parent = NA` signals a non-chained rethrow

Code
  # Absent parent causes bad trace bottom
  hh <- (function() {
    withCallingHandlers(foo(), error = function(cnd) {
      abort(cnd_header(cnd))
    })
  })
  print(err(ff()))
Output
  <error/rlang_error>
  Error in `h()`:
  ! bar
  ---
  Backtrace:
       x
    1. +-base::print(err(ff()))
    2. +-rlang:::err(ff())
    3. | \-testthat::expect_error(...)
    4. |   \-testthat:::expect_condition_matching(...)
    5. |     \-testthat:::quasi_capture(...)
    6. |       +-testthat (local) .capture(...)
    7. |       | \-base::withCallingHandlers(...)
    8. |       \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    9. +-rlang (local) ff()
   10. | \-rlang (local) gg()
   11. |   \-rlang (local) hh()
   12. |     +-base::withCallingHandlers(...)
   13. |     \-rlang (local) foo()
   14. |       \-rlang (local) bar()
   15. |         \-rlang (local) baz()
   16. |           \-base::stop("bar")
   17. \-base::.handleSimpleError(`<fn>`, "bar", base::quote(baz()))
   18.   \-rlang (local) h(simpleError(msg, call))
Code
  # Missing parent allows correct trace bottom
  hh <- (function() {
    withCallingHandlers(foo(), error = function(cnd) {
      abort(cnd_header(cnd), parent = NA)
    })
  })
  print(err(ff()))
Output
  <error/rlang_error>
  Error in `hh()`:
  ! bar
  ---
  Backtrace:
       x
    1. +-base::print(err(ff()))
    2. +-rlang:::err(ff())
    3. | \-testthat::expect_error(...)
    4. |   \-testthat:::expect_condition_matching(...)
    5. |     \-testthat:::quasi_capture(...)
    6. |       +-testthat (local) .capture(...)
    7. |       | \-base::withCallingHandlers(...)
    8. |       \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    9. \-rlang (local) ff()
   10.   \-rlang (local) gg()
   11.     \-rlang (local) hh()
   12.       +-base::withCallingHandlers(...)
   13.       \-rlang (local) foo()
   14.         \-rlang (local) bar()
   15.           \-rlang (local) baz()
   16.             \-base::stop("bar")
Code
  # Wrapped handler
  handler1 <- (function(cnd, call = caller_env()) handler2(cnd, call))
  handler2 <- (function(cnd, call) abort(cnd_header(cnd), parent = NA, call = call))
  hh <- (function() {
    withCallingHandlers(foo(), error = function(cnd) handler1(cnd))
  })
  print(err(ff()))
Output
  <error/rlang_error>
  Error in `hh()`:
  ! bar
  ---
  Backtrace:
       x
    1. +-base::print(err(ff()))
    2. +-rlang:::err(ff())
    3. | \-testthat::expect_error(...)
    4. |   \-testthat:::expect_condition_matching(...)
    5. |     \-testthat:::quasi_capture(...)
    6. |       +-testthat (local) .capture(...)
    7. |       | \-base::withCallingHandlers(...)
    8. |       \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    9. \-rlang (local) ff()
   10.   \-rlang (local) gg()
   11.     \-rlang (local) hh()
   12.       +-base::withCallingHandlers(foo(), error = function(cnd) handler1(cnd))
   13.       \-rlang (local) foo()
   14.         \-rlang (local) bar()
   15.           \-rlang (local) baz()
   16.             \-base::stop("bar")
Code
  # Wrapped handler, `try_fetch()`
  hh <- (function() {
    try_fetch(foo(), error = function(cnd) handler1(cnd))
  })
  print(err(ff()))
Output
  <error/rlang_error>
  Error in `hh()`:
  ! bar
  ---
  Backtrace:
       x
    1. +-base::print(err(ff()))
    2. +-rlang:::err(ff())
    3. | \-testthat::expect_error(...)
    4. |   \-testthat:::expect_condition_matching(...)
    5. |     \-testthat:::quasi_capture(...)
    6. |       +-testthat (local) .capture(...)
    7. |       | \-base::withCallingHandlers(...)
    8. |       \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    9. \-rlang (local) ff()
   10.   \-rlang (local) gg()
   11.     \-rlang (local) hh()
   12.       +-rlang::try_fetch(foo(), error = function(cnd) handler1(cnd))
   13.       | +-base::tryCatch(...)
   14.       | | \-base (local) tryCatchList(expr, classes, parentenv, handlers)
   15.       | |   \-base (local) tryCatchOne(expr, names, parentenv, handlers[[1L]])
   16.       | |     \-base (local) doTryCatch(return(expr), name, parentenv, handler)
   17.       | \-base::withCallingHandlers(...)
   18.       \-rlang (local) foo()
   19.         \-rlang (local) bar()
   20.           \-rlang (local) baz()
   21.             \-base::stop("bar")
Code
  # Wrapped handler, incorrect `call`
  hh <- (function() {
    withCallingHandlers(foo(), error = handler1)
  })
  print(err(ff()))
Output
  <error/rlang_error>
  Error in `.handleSimpleError()`:
  ! bar
  ---
  Backtrace:
       x
    1. +-base::print(err(ff()))
    2. +-rlang:::err(ff())
    3. | \-testthat::expect_error(...)
    4. |   \-testthat:::expect_condition_matching(...)
    5. |     \-testthat:::quasi_capture(...)
    6. |       +-testthat (local) .capture(...)
    7. |       | \-base::withCallingHandlers(...)
    8. |       \-rlang::eval_bare(quo_get_expr(.quo), quo_get_env(.quo))
    9. \-rlang (local) ff()
   10.   \-rlang (local) gg()
   11.     \-rlang (local) hh()
   12.       +-base::withCallingHandlers(foo(), error = handler1)
   13.       \-rlang (local) foo()
   14.         \-rlang (local) bar()
   15.           \-rlang (local) baz()
   16.             \-base::stop("bar")