error handling quosures (#65)

NAMESPACE

@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+S3method("[[",quosure.error)
 export(chunk)
 export(chunk_call)
 export(chunk_comment)
@@ -42,7 +43,9 @@ exportMethods(get_code)
 exportMethods(get_var)
 exportMethods(join)
 exportMethods(new_quosure)
+exportMethods(show)
 import(shiny)
 importFrom(R6,R6Class)
 importFrom(lifecycle,badge)
+importFrom(methods,show)
 importFrom(styler,style_text)

R/quosure-class.R

@@ -16,6 +16,7 @@ setClass(
 )
 
 #' It takes a `Quosure` class and returns TRUE if the input is valid
+#' @name Quosure-class
 #' @keywords internal
 setValidity("Quosure", function(object) {
   if (length(object@code) != length(object@id)) {

R/quosure-errors.R

@@ -0,0 +1,2 @@
+# needed to handle try-error
+setOldClass("quosure.error")

R/quosure-eval_code.R

@@ -22,47 +22,56 @@ setGeneric("eval_code", function(object, code, name = "code") {
 
 #' @rdname eval_code
 #' @export
-setMethod(
-  "eval_code",
-  signature = c("Quosure", "character"),
-  function(object, code, name) {
-    checkmate::assert_string(name)
-    if (is.null(names(code))) {
-      code <- paste(code, collapse = "\n")
-      names(code) <- name
-    }
-    id <- sample.int(.Machine$integer.max, size = length(code))
-    object@id <- c(object@id, id)
-    object@code <- .keep_code_name_unique(object@code, code)
-
-    # need to copy the objects from old env to new env
-    # to avoid updating environments in the separate objects
-    object@env <- .copy_env(object@env)
-    eval(parse(text = code), envir = object@env)
-    lockEnvironment(object@env)
-    object
+setMethod("eval_code", signature = c("Quosure", "character"), function(object, code, name) {
+  checkmate::assert_string(name)
+  if (is.null(names(code))) {
+    code <- paste(code, collapse = "\n")
+    names(code) <- name
   }
-)
+  id <- sample.int(.Machine$integer.max, size = length(code))
+
+  object@id <- c(object@id, id)
+  object@code <- .keep_code_name_unique(object@code, code)
+
+  # need to copy the objects from old env to new env
+  # to avoid updating environments in the separate objects
+  object@env <- .copy_env(object@env)
+  tryCatch(
+    {
+      eval(parse(text = code), envir = object@env)
+      lockEnvironment(object@env)
+      object
+    },
+    error = function(e) {
+      errorCondition(
+        message = sprintf(
+          "%s \n when evaluating Quosure code:\n %s",
+          conditionMessage(e),
+          paste(code, collapse = "\n ")
+        ),
+        class = c("quosure.error", "try-error", "simpleError"),
+        trace = object@code
+      )
+    }
+  )
+})
 
 #' @rdname eval_code
 #' @export
-setMethod(
-  "eval_code",
-  signature = c("Quosure", "expression"),
-  function(object, code, name) {
-    code_char <- as.character(code)
-    eval_code(object, code_char, name = name)
-  }
-)
+setMethod("eval_code", signature = c("Quosure", "expression"), function(object, code, name) {
+  code_char <- as.character(code)
+  eval_code(object, code_char, name = name)
+})
 
 #' @rdname eval_code
 #' @export
-setMethod(
-  "eval_code",
-  signature = c("Quosure", "language"),
-  function(object, code, name) {
-    code_char <- as.expression(code)
-    eval_code(object, code_char, name = name)
-  }
-)
+setMethod("eval_code", signature = c("Quosure", "language"), function(object, code, name) {
+  code_char <- as.expression(code)
+  eval_code(object, code_char, name = name)
+})
 
+#' @rdname eval_code
+#' @export
+setMethod("eval_code", signature = "quosure.error", function(object, code, name) {
+  object
+})

R/quosure-get_code.R

@@ -12,6 +12,10 @@
 #'
 #' @export
 setGeneric("get_code", function(object) {
+  # this line forces evaluation of object before passing to the generic
+  # needed for error handling to work properly
+  object
+
   standardGeneric("get_code")
 })
 
@@ -20,3 +24,18 @@ setGeneric("get_code", function(object) {
 setMethod("get_code", signature = "Quosure", function(object) {
   object@code
 })
+
+#' @rdname get_code
+#' @export
+setMethod("get_code", signature = "quosure.error", function(object) {
+  stop(
+    errorCondition(
+      sprintf(
+        "%s\n\ntrace: \n %s\n",
+        conditionMessage(object),
+        paste(object$trace, collapse = "\n ")
+      ),
+      class = c("validation", "try-error", "simpleError")
+    )
+  )
+})

R/quosure-get_var.R

@@ -22,12 +22,31 @@ setMethod("get_var", signature = c("Quosure", "character"), function(object, var
   get(var, envir = object@env)
 })
 
+#' @rdname get_var
+#' @export
+setMethod("get_var", signature = "quosure.error", function(object, var) {
+  stop(errorCondition(
+    list(message = conditionMessage(object)),
+    class = c("validation", "try-error", "simpleError")
+  ))
+})
+
+
 #' @param x (`Quosure`)
 #' @param i (`character`) name of the binding in environment (name of the variable)
 #' @param j not used
 #' @param ... not used
 #' @rdname get_var
 #' @export
-setMethod("[[", c("Quosure", "ANY", "missing"), function(x, i, j, ...) {
+setMethod("[[", signature = c("Quosure", "ANY", "missing"), function(x, i, j, ...) {
   get_var(x, i)
 })
+
+#' @rdname get_var
+#' @export
+`[[.quosure.error` <- function(x, i, j, ...) {
+  stop(errorCondition(
+    list(message = conditionMessage(x)),
+    class = c("validation", "try-error", "simpleError")
+  ))
+}

R/quosure-join.R

@@ -48,6 +48,18 @@ setMethod("join", signature = c("Quosure", "Quosure"), function(x, y) {
   x
 })
 
+#' @rdname join
+#' @export
+setMethod("join", signature = "quosure.error", function(x, y) {
+  x
+})
+
+#' @rdname join
+#' @export
+setMethod("join", signature = c("Quosure", "quosure.error"), function(x, y) {
+  y
+})
+
 #' If two `Quosure` can be joined
 #'
 #' Checks if two `Quosure` objects can be combined.

R/quosure-show.R

@@ -0,0 +1,18 @@
+#' Show the `Quosure` object
+#'
+#' Prints the `Quosure` object
+#' @param object (`Quosure`)
+#' @return nothing
+#' @importFrom methods show
+#' @examples
+#' q1 <- new_quosure(code = "print('a')", env = new.env())
+#' q1
+#' @export
+setMethod("show", "Quosure", function(object) {
+  obs <- names(as.list(object@env))
+  if (length(obs) > 0) {
+    cat(paste("A quosure object containing:", paste(obs, collapse = ", ")))
+  } else {
+    cat("A quosure object containing no objects")
+  }
+})

tests/testthat/test-eval_code.R

@@ -8,7 +8,7 @@ testthat::test_that("eval_code doesn't have access to environment where it's cal
   a <- 1L
   q1 <- new_quosure("a <- 1", env = environment())
   b <- 2L
-  testthat::expect_error(eval_code(q1, "d <- b"), "object 'b' not found")
+  testthat::expect_s3_class(eval_code(q1, "d <- b"), c("quosure.error", "try-error", "error", "condition"))
 })
 
 testthat::test_that("@env in quosure is always a sibling of .GlobalEnv", {
@@ -30,15 +30,15 @@ testthat::test_that("library have to be called separately before using function
   testthat::expect_identical(parent.env(q2@env), parent.env(.GlobalEnv))
 
   detach("package:checkmate", unload = TRUE)
-  testthat::expect_error(
+  testthat::expect_s3_class(
     eval_code(
       new_quosure(),
       as.expression(c(
         quote(library(checkmate)),
         quote(assert_number(1))
       ))
     ),
-    "could not find function \"assert_number\""
+    "quosure.error"
   )
 })
 
@@ -89,7 +89,16 @@ testthat::test_that("each eval_code adds name to passed code", {
   testthat::expect_identical(q3@code, c(test = "a <- 1", test2 = "b <- 2"))
 })
 
-testthat::test_that("get_code make name of the code block unique if duplicated", {
+testthat::test_that("an error when calling eval_code returns a quosure.error object which has message and trace", {
+  q <- eval_code(new_quosure(), "x <- 1")
+  q <- eval_code(q, "y <- 2")
+  q <- eval_code(q, "z <- w * x")
+  testthat::expect_s3_class(q, "quosure.error")
+  testthat::expect_equal(unname(q$trace), c("x <- 1", "y <- 2", "z <- w * x"))
+  testthat::expect_equal(q$message, "object 'w' not found \n when evaluating Quosure code:\n z <- w * x")
+})
+
+testthat::test_that("eval_code make name of the code block unique if duplicated", {
   q1 <- new_quosure()
   q2 <- eval_code(q1, code = "a <- 1", name = "test")
   q3 <- eval_code(q2, code = "b <- 2", name = "test")

tests/testthat/test-quosure-get_code.R

@@ -0,0 +1,21 @@
+testthat::test_that("get_code returns code of Quosure object", {
+  q <- new_quosure(list2env(list(x = 1)), code = "x <- 1")
+  q <- eval_code(q, "y <- x", name = "next_code")
+  testthat::expect_equal(get_code(q), c("initial code" = "x <- 1", "next_code" = "y <- x"))
+})
+
+testthat::test_that("get_code called with quosure.error returns error with trace in error message", {
+  q <- new_quosure(list2env(list(x = 1)), code = "x <- 1")
+  q <- eval_code(q, "y <- x")
+  q <- eval_code(q, "w <- v")
+
+  code <- tryCatch(
+    get_code(q),
+    error = function(e) e
+  )
+  testthat::expect_equal(class(code), c("validation", "try-error", "simpleError", "error", "condition"))
+  testthat::expect_equal(
+    code$message,
+    "object 'v' not found \n when evaluating Quosure code:\n w <- v\n\ntrace: \n x <- 1\n y <- x\n w <- v\n"
+  )
+})