Merge pull request #1689 from rstudio/subset-loads-delayed-module

`[[` loads lazy modules

NEWS.md

@@ -1,5 +1,7 @@
 # reticulate (development version)
 
+- `[[` now loads delayed modules (#1688).
+
 - Fixed error when attempting to use a python venv created with `uv` (#1678)
 
 - Fixed error where `py_discover_config()` attempted to detect

src/reticulate_types.h

@@ -129,8 +129,10 @@ class PyObjectRef: public Rcpp::RObject {
     SEXP xptr = Rf_findVarInFrame(get_refenv(), sym_pyobj);
     if(TYPEOF(xptr) == EXTPTRSXP)
       return ((PyObject*) R_ExternalPtrAddr(xptr) == NULL);
-    if(xptr == R_UnboundValue || xptr == R_NilValue)
-      return true; // return true for lazy module proxy
+    if(xptr == R_UnboundValue)
+      return false; // return false for lazy module proxy
+    if(xptr == R_NilValue)
+      return true; // ??? manually finalized obj? ??? should never happen ???
     return false; // should never happen
   }
 

tests/testthat/test-delay-load.R

@@ -20,13 +20,13 @@ test_that("imported module can be customized via delay_load", {
     stopifnot(isTRUE(reticulate:::py_is_module_proxy(sys)))
 
     print(sys)
-    stopifnot(isTRUE(reticulate::py_is_null_xptr(sys)))
     stopifnot(isTRUE(reticulate:::py_is_module_proxy(sys)))
+    stopifnot(isFALSE(reticulate::py_available()))
 
     out <- as.character(sys$byteorder)
 
-    stopifnot(isFALSE(reticulate::py_is_null_xptr(sys)))
     stopifnot(isFALSE(reticulate:::py_is_module_proxy(sys)))
+    stopifnot(isTRUE(reticulate::py_available()))
 
     out
   })
@@ -35,3 +35,25 @@ test_that("imported module can be customized via delay_load", {
   expect_true(result %in% c("little", "big"))
 
 })
+
+
+test_that("[[ loads delayed modules", {
+
+  # https://github.com/rstudio/reticulate/issues/1688
+  config <- py_config()
+  withr::local_envvar(RETICULATE_PYTHON = config$python)
+
+  result <- callr::r(function() {
+    time <- reticulate::import('time', delay_load = TRUE)
+    stopifnot(isFALSE(reticulate::py_available()))
+
+    result <- time[['time']]()
+    stopifnot(isTRUE(reticulate::py_available()))
+    result
+  })
+
+  # validate expected result
+  expect_true(typeof(result) %in% c("double", "integer"))
+  expect_true((result - import("time")$time()) < 10)
+
+})