patch subprocess.Popen on Windows/Rstudio

closes #1448
closes #518
closes

NEWS.md

@@ -1,13 +1,16 @@
 # reticulate (development version)
 
 - reticulate now exports a `chooseOpsMethod()` method, allowing for Ops dispatch 
-  to more specialized Ops methods defined for Python objects. 
+  to more specialized Ops methods defined for Python objects.
 
 - reticulate now supports casting R data.frames to Pandas data.frames using nullable
   data types allowing users to preserve NA's from R atomic vectors. This feature is
   opt-in and can be enabled by setting the R option `reticulate.pandas_use_nullable_dtypes`
   to `TRUE`. (#1439)
 
+- Fixed issue where Python would raise an exception when opening a subprocess while
+  running in Rstudio on Windows. (#1448, #518)
+
 - Fixed issue where `virtualenv_create()` would fail to discover a 'virtualenv' module 
   in the system Python installation on Ubuntu. Reticulate will no longer discover 
   and attempt to use the `venv` module stub present on Ubuntu systems

R/package.R

@@ -66,6 +66,9 @@ ensure_python_initialized <- function(required_module = NULL) {
   remap_output_streams()
   set_knitr_python_stdout_hook()
 
+  if (is_windows() && identical(.Platform$GUI, "RStudio"))
+    import("rpytools.subprocess")$patch_subprocess_Popen()
+
   # generate 'R' helper object
   py_inject_r()
 

inst/python/rpytools/subprocess.py

@@ -0,0 +1,9 @@
+# When running on Windows in RStudio, we need to patch subprocess.Popen
+# https://github.com/rstudio/reticulate/issues/1448
+
+
+def patch_subprocess_Popen():
+  import subprocess
+  from functools import partial
+
+  subprocess.Popen = partial(subprocess.Popen, stdin = subprocess.DEVNULL)

tests/testthat/test-subprocess.R

@@ -0,0 +1,18 @@
+context("subprocess module")
+
+test_that("subprocess.Popen works", {
+
+  subprocess <- import("subprocess")
+
+  # needs patching on Windows in the RStudio IDE
+  # https://github.com/rstudio/reticulate/issues/1448
+  expect_no_error({
+    subprocess$Popen(
+      c("ls", "."),
+      shell = FALSE,
+      stderr = subprocess$PIPE,
+      stdout = subprocess$PIPE
+    )
+  })
+
+})