Try even harder to suppress pak's output (#2681)

Somehow the nested use of callr (first layer is parallel testthat workers, second layer is inside pak) gives rise to some very difficult to suppress output. This is just about reducing noise in the testthat report.

Author: jennybc

R/install.R

@@ -80,14 +80,26 @@ install <- function(
     if (quiet) {
       withr::local_output_sink(withr::local_tempfile())
       withr::local_message_sink(withr::local_tempfile())
+      # pak uses callr internally. When install() itself runs inside a callr
+      # worker (e.g. testthat parallel tests), pak's callr_message conditions
+      # leak to the parent process. Muffle them here; tryInvokeRestart() is a
+      # safe no-op when the muffleMessage restart doesn't exist.
+      withCallingHandlers(
+        pak::local_install_deps(
+          pkg$path,
+          upgrade = upgrade,
+          dependencies = dependencies || isTRUE(build_vignettes)
+        ),
+        callr_message = function(cnd) tryInvokeRestart("muffleMessage")
+      )
     } else {
       cli::cat_rule("pak::local_install_deps()", col = "cyan")
+      pak::local_install_deps(
+        pkg$path,
+        upgrade = upgrade,
+        dependencies = dependencies || isTRUE(build_vignettes)
+      )
     }
-    pak::local_install_deps(
-      pkg$path,
-      upgrade = upgrade,
-      dependencies = dependencies || isTRUE(build_vignettes)
-    )
   })
 
   if (isTRUE(build_vignettes)) {