Add utils to check for lint and error classes (#2681)

Author: IndrajeetPatil

R/extract.R

@@ -9,7 +9,7 @@ extract_r_source <- function(filename, lines, error = identity) {
   output <- rep.int(NA_character_, length(lines))
 
   chunks <- tryCatch(get_chunk_positions(pattern = pattern, lines = lines), error = error)
-  if (inherits(chunks, "error") || inherits(chunks, "lint")) {
+  if (is_error(chunks) || is_lint(chunks)) {
     assign("e", chunks, envir = parent.frame())
     # error, so return empty code
     return(output)

R/get_source_expressions.R

@@ -86,7 +86,7 @@ get_source_expressions <- function(filename, lines = NULL) {
   source_expression$content <- get_content(source_expression$lines)
   parsed_content <- get_source_expression(source_expression, error = function(e) lint_parse_error(e, source_expression))
 
-  if (inherits(e, "lint") && (is.na(e$line) || !nzchar(e$line) || e$message == "unexpected end of input")) {
+  if (is_lint(e) && (is.na(e$line) || !nzchar(e$line) || e$message == "unexpected end of input")) {
     # Don't create expression list if it's unreliable (invalid encoding or unhandled parse error)
     expressions <- list()
   } else {
@@ -502,7 +502,7 @@ get_source_expression <- function(source_expression, error = identity) {
     error = error
   )
 
-  if (inherits(parsed_content, c("error", "lint"))) {
+  if (is_error(parsed_content) || is_lint(parsed_content)) {
     assign("e", parsed_content, envir = parent.frame())
     parse_error <- TRUE
   }
@@ -513,7 +513,7 @@ get_source_expression <- function(source_expression, error = identity) {
     error = error
   )
 
-  if (inherits(parsed_content, c("error", "lint"))) {
+  if (is_error(parsed_content) || is_lint(parsed_content)) {
     # Let parse errors take precedence over encoding problems
     if (!parse_error) assign("e", parsed_content, envir = parent.frame())
     return() # parsed_content is unreliable if encoding is invalid

R/lint.R

@@ -696,7 +696,7 @@ maybe_report_progress <- function(pb) {
 }
 
 maybe_append_error_lint <- function(lints, error, lint_cache, filename) {
-  if (inherits(error, "lint")) {
+  if (is_lint(error)) {
     error$linter <- "error"
     lints[[length(lints) + 1L]] <- error
 

R/utils.R

@@ -245,9 +245,12 @@ get_r_string <- function(s, xpath = NULL) {
 }
 
 is_linter <- function(x) inherits(x, "linter")
+is_lint <- function(x) inherits(x, "lint")
+
+is_error <- function(x) inherits(x, "error")
 
 is_tainted <- function(lines) {
-  inherits(tryCatch(nchar(lines), error = identity), "error")
+  is_error(tryCatch(nchar(lines), error = identity))
 }
 
 #' Check that the entries in ... are valid