Prevent $run() method while plumb()ing file (#574)

Co-authored-by: Bruno Tremblay <meztez@neoxone.com>
Co-authored-by: Barret Schloerke <barret@rstudio.com>

R/plumber.R

@@ -233,6 +233,10 @@ plumber <- R6Class(
       if (!is.null(file)){
         private$lines <- readUTF8(file)
         private$parsed <- parseUTF8(file)
+        private$disable_run <- TRUE
+        on.exit({
+          private$disable_run <- FALSE
+        }, add = TRUE)
 
         for (i in 1:length(private$parsed)){
           e <- private$parsed[i]
@@ -288,6 +292,10 @@ plumber <- R6Class(
       debug = interactive(),
       swaggerCallback = getOption('plumber.swagger.url', NULL)
     ) {
+      if (isTRUE(private$disable_run)) {
+        stop("Plumber router `$run()` method should not be called while `plumb()`ing a file")
+      }
+
       port <- findPort(port)
 
 
@@ -1056,6 +1064,7 @@ plumber <- R6Class(
     lines = NULL, # The lines constituting the API
     parsed = NULL, # The parsed representation of the API
     globalSettings = list(info=list()), # Global settings for this API. Primarily used for OpenAPI Specification.
+    disable_run = NULL, # Disable run method during parsing of the Plumber file
 
     errorHandler = NULL,
     notFoundHandler = NULL,

tests/testthat/files/router-modifier-run.R

@@ -0,0 +1,4 @@
+#* @plumber
+function(pr){
+  pr$run()
+}

tests/testthat/test-router-modifier.R

@@ -1,6 +1,9 @@
 context("Router modifier (@plumber tag)")
 
-test_that("router modifier tag works correctly", {
+test_that("router modifier works, run does nothing", {
+  expect_error(
+    plumber$new(test_path("files/router-modifier-run.R")),
+    "method should not be called while")
   pr <- plumber$new(test_path("files/router-modifier.R"))
   expect_equal(class(pr$routes[[1]])[1], "PlumberEndpoint")
   expect_equal(names(pr$routes), "avatartare")