Correctly interpolate dangerous string into cli warning

Fixes #1575

DESCRIPTION

@@ -53,4 +53,4 @@ Config/testthat/parallel: TRUE
 Encoding: UTF-8
 Language: en-GB
 Roxygen: list(markdown = TRUE, load = "installed")
-RoxygenNote: 7.2.3.9000
+RoxygenNote: 7.3.0.9000

NEWS.md

@@ -1,6 +1,9 @@
 # roxygen2 (development version)
 
+* S3 method export warning no longer fails if class contains `{` or `}` (#1575).
+
 * `@family` lists are now ordered more carefully, "foo1" comes after "foo" (#1563, @krlmlr).
+
 * Re-runs of `namespace_roclet()` fixed for packages using multi-line `@rawNamespace` directives (#1572, @MichaelChirico).
 
 * `@importFrom` works again for quoted non-syntactic names, e.g.

R/namespace.R

@@ -401,7 +401,11 @@ warn_missing_s3_exports <- function(blocks, env) {
 
   undocumented <- methods[!methods %in% s3objects]
   srcrefs <- map(undocumented, attr, "srcref")
-  messages <- paste0("S3 method `", names(undocumented) , "` needs @export or @exportS3method tag")
-  map2(undocumented, messages, warn_roxy_function)
-}
 
+  map2(undocumented, names(undocumented), function(fun, name) {
+    warn_roxy_function(
+      fun,
+      "S3 method {.arg {name}} needs @export or @exportS3method tag"
+    )
+  })
+}

tests/testthat/_snaps/namespace.md

@@ -103,3 +103,13 @@
     Output
       character(0)
 
+# correctly interpolates warning
+
+    Code
+      roc_proc_text(namespace_roclet(),
+      "\n      foo <- function(x) UseMethod('foo')\n      `foo.{` <- function(x) 1\n    ")
+    Message
+      x <text>:3: S3 method `foo.{` needs @export or @exportS3method tag.
+    Output
+      character(0)
+

tests/testthat/test-namespace.R

@@ -485,6 +485,18 @@ test_that("warns if S3 method not documented", {
   )
 })
 
+test_that("correctly interpolates warning", {
+  expect_snapshot(
+    roc_proc_text(namespace_roclet(), "
+      foo <- function(x) UseMethod('foo')
+      `foo.{` <- function(x) 1
+    "),
+    # Need to manually transform since the srcref is coming from the function;
+    # roc_proc_text() uses fake srcrefs for the blocks themselves
+    transform = function(x) gsub("file[a-z0-9]+", "<text>", x)
+  )
+})
+
 
 test_that("can suppress the warning", {
   block <- "