when the connection is no longer valid, mention the most likely reaso…

…n: closeAllConnections() might have been called

quarto-dev/quarto-cli#5214

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: evaluate
 Type: Package
 Title: Parsing and Evaluation Tools that Provide More Details than the Default
-Version: 0.20.1
+Version: 0.20.2
 Authors@R: c(
     person("Hadley", "Wickham", role = "aut"),
     person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),

NEWS.md

@@ -5,6 +5,8 @@ Version 0.21
   these cause code and warnings (respectively) to be immediately emitted to 
   `stderr()`. This is useful for logging in unattended environments (#118).
 
+- Improved the error message when users accidentally called `closeAllConnections()` (thanks, @guslipkin, quarto-dev/quarto-cli#5214).
+
 Version 0.20
 ================================================================================
 

R/watcher.R

@@ -15,7 +15,7 @@ watchout <- function(debug = FALSE) {
   list(
     get_new = function(plot = FALSE, incomplete_plots = FALSE,
                        text_callback = identity, graphics_callback = identity) {
-      incomplete <- isIncomplete(con)
+      incomplete <- test_con(con, isIncomplete)
       if (incomplete) cat("\n")
 
       out <- list()
@@ -42,8 +42,7 @@ watchout <- function(debug = FALSE) {
     pause = function() sink(),
     unpause = function() sink(con, split = debug),
     close = function() {
-      if (!isOpen(con))
-        stop("something bad happened... did you use closeAllConnections()?")
+      test_con(con, isOpen)
       sink()
       close(con)
       output
@@ -52,6 +51,12 @@ watchout <- function(debug = FALSE) {
   )
 }
 
+test_con = function(con, test) {
+  tryCatch(test(con), error = function(e) stop(
+    e$message, '... Please make sure not to call closeAllConnections().'
+  ))
+}
+
 .env = new.env()
 .env$flush_console = function() {}