Fix the check for service account JSON

NEWS.md

@@ -1,5 +1,9 @@
 # gargle (development version)
 
+* Fixed a bug in an internal helper that validates input specifying a service
+  account. The helper targets a common mistake where the JSON for an OAuth
+  client is provided to an argument that is meant for a service account (#270).
+
 # gargle 1.5.1
 
 * Completed some overlooked, unfinished work around the OAuth "app" to "client"

R/credentials_service_account.R

@@ -85,12 +85,12 @@ check_is_service_account <- function(path, hint, call = caller_env()) {
     return(invisible())
   }
 
-  tryCatch(
-    info <- jsonlite::fromJSON(path, simplifyVector = FALSE),
-    error = NULL
+  info <- tryCatch(
+    jsonlite::fromJSON(path, simplifyVector = FALSE),
+    error = function(e) NULL
   )
 
-  if (!is.null(info) && !identical(info[["type"]], "service_account")) {
+  if (is.null(info) || !identical(info[["type"]], "service_account")) {
     cli::cli_abort(c(
       "{.arg path} does not represent a service account.",
       "Did you provide the JSON for an OAuth client instead of for a \\

tests/testthat/_snaps/credentials_service_account.md

@@ -9,3 +9,13 @@
       Did you provide the JSON for an OAuth client instead of for a service account?
       Use `PKG_auth_configure()` to configure the OAuth client.
 
+# check_is_service_account() errors for invalid input
+
+    Code
+      PKG_auth("wut")
+    Condition
+      Error in `PKG_auth()`:
+      ! `path` does not represent a service account.
+      Did you provide the JSON for an OAuth client instead of for a service account?
+      Use `PKG_auth_configure()` to configure the OAuth client.
+

tests/testthat/test-credentials_service_account.R

@@ -10,3 +10,14 @@ test_that("check_is_service_account() errors for OAuth client", {
     )
   )
 })
+
+test_that("check_is_service_account() errors for invalid input", {
+  # call indirectly, so we can also check the caller is reported
+  PKG_auth <- function(path) {
+    check_is_service_account(path, hint = "PKG_auth_configure")
+  }
+  expect_snapshot(
+    error = TRUE,
+    PKG_auth("wut")
+  )
+})