context("exceptions") test_that("py_last_error() returns R strings", { skip_if_no_python() tryCatch(py_eval("range(3)[3]"), error = identity) er <- py_last_error() expect_identical(er$type, "IndexError") expect_type(er$value, "character") expect_type(er$traceback, "character") expect_type(er$message, "character") }) test_that("py_last_error() returns the R error condition object", { skip_if_no_python() signal_simple_error <- function() { stop("Hello signal_simple_error") } raise_py_exception <- function() { py_run_string("raise RuntimeError('Hello raise_py_exception')") } signal_py_exception <- function() { stop(import_builtins()$RuntimeError("Hello signal_py_exception")) } f1 <- py_func(signal_simple_error) f2 <- py_func(function() f1()) f3 <- py_func(function() f2()) f4 <- py_func(function() f3()) g1 <- py_func(raise_py_exception) g2 <- py_func(function() g1()) g3 <- py_func(function() g2()) g4 <- py_func(function() g3()) h1 <- py_func(signal_py_exception) h2 <- py_func(function() h1()) h3 <- py_func(function() h2()) h4 <- py_func(function() h3()) for (fn in list(f1, f2, f3, f4, g1, g2, g3, g4, h1, h2, h3, h4)) { e <- tryCatch( fn(), error = function(e) e ) for (cls in c("python.builtin.Exception", "python.builtin.BaseException", "python.builtin.object", "error", "condition")) expect_s3_class(e, cls) expect_identical(conditionMessage(e), e$message) expect_identical(conditionCall(e), e$call) expect_match(conditionMessage(e), "Hello") expect_type(conditionCall(e), "language") expect_s3_class(e$trace, "data.frame") expect_s3_class(e$trace, "rlang_trace") } # test that py_last_error() reports full r_trace # even if python discards the exception object catch_and_replace_exception <- py_run_string(" def catch_and_replace_exception(fn): try: fn() except: raise RuntimeError('''It's a mystery!''') ")$catch_and_replace_exception catch_clear_errstatus_then_raise_new_exception <- py_run_string(" def catch_clear_errstatus_then_raise_new_exception(fn): failed = False try: res = fn() except: failed = True if failed: raise RuntimeError('''It's a mystery!''') return res ")$catch_clear_errstatus_then_raise_new_exception expect_match2 <- expect_match formals(expect_match2)$fixed <- TRUE formals(expect_match2)$all <- FALSE for (erroring_fn in list(signal_simple_error, raise_py_exception, signal_py_exception)) { f1 <- py_func(erroring_fn) f2 <- py_func(function() f1()) f3 <- py_func(function() catch_and_replace_exception(f2)) f4 <- py_func(function() f3()) f5 <- py_func(function() f4()) e <- tryCatch(f5(), error = identity) expect_s3_class(e$trace, "data.frame") expect_s3_class(e$trace, "rlang_trace") output <- suppressMessages(capture.output(print(reticulate::py_last_error()))) expect_match2(output, "Hello") expect_match2(output, "It's a mystery!") expect_match2(output, "f1()") expect_match2(output, "catch_and_replace_exception(f2)") expect_match2(output, "f3()") expect_match2(output, "f4()") expect_match2(output, "f5()") f1 <- py_func(erroring_fn) f2 <- py_func(function() f1()) f3 <- py_func(function() catch_clear_errstatus_then_raise_new_exception(f2)) f4 <- py_func(function() f3()) f5 <- py_func(function() f4()) e <- tryCatch(f5(), error = identity) expect_s3_class(e$trace, "data.frame") expect_s3_class(e$trace, "rlang_trace") output <- suppressMessages(capture.output(print(reticulate::py_last_error()))) expect_match2(output, "It's a mystery!") # python code made it a mystery expect_match2(output, "Hello") # we make it not a mystery by providing the R trace expect_match2(output, "f1()") expect_match2(output, "catch_clear_errstatus_then_raise_new_exception(f2)") expect_match2(output, "f3()") expect_match2(output, "f4()") expect_match2(output, "f5()") } })