Merge pull request #1687 from rstudio/bugfix/positron-io-reset

Fix Positron stdout redirection after Ipykernel closes

R/thread.R

@@ -63,6 +63,11 @@ py_run_file_on_thread <- function(file, ..., args = NULL) {
   if (launching_lsp) {
     main_dict <- py_eval("__import__('__main__').__dict__.copy()", FALSE)
     py_get_attr(main_dict, "pop")("__annotations__")
+    # IPykernel will create a thread that redirects all output from fileno of
+    # the current sys.stdout and sys.stderr to its IO channels.
+    # This is not correctly cleaned up when IPykernel closes.
+    # To fix that, we set the IO streams to /dev/null before launching the kernel.
+    import("rpytools.run")$set_blank_io_streams()
   }
 
   import("rpytools.run")$run_file_on_thread(file, args, ...)

inst/python/rpytools/run.py

@@ -50,6 +50,13 @@ def _launch_lsp_server_on_thread(path, args):
     return run_file_on_thread(path, args)
 
 
+def set_blank_io_streams():
+    import sys
+    import os
+    sys.stdout = open(os.devnull, "w")
+    sys.stderr = open(os.devnull, "w")
+
+
 def run_file_on_thread(path, argv=None, init_globals=None, run_name="__main__"):
     # for now, leave sys.argv and sys.path permanently modified.
     # Later, revisit if it's desirable/safe to restore after the initial