changes from feedback on knitr #1518 with updated tests

Author: tmastny

R/knitr-engine.R

@@ -322,18 +322,19 @@ save_python_session <- function(cache_path) {
 #' Typically, this will be set within a document's setup chunk, or by the
 #' environment requesting that Python chunks be processed by this engine.
 #' 
-#' @param cache_path
-#'   The path to save the chunk cache, as provided by `knitr` during chunk execution.
+#' @param options
+#'   List of chunk options provided by `knitr` during chunk execution. 
+#'   Contains the caching path.
 #'   
 #' @export
-cache_eng_python <- function(cache_path) {
+cache_eng_python <- function(options) {
   module <- tryCatch(import("dill"), error = identity)
   if (inherits(module, "error")) {
     if (module$message == "ImportError: No module named dill") return()
     stop(module$message)
   }
 
-  module$load_session(filename = paste0(cache_path, ".pkl"))
+  module$load_session(filename = paste0(options$hash, ".pkl"))
 }
 
 

man/cache_eng_python.Rd

@@ -5,8 +5,6 @@ title: "Using reticulate's Python Engine with knitr"
 ```{r setup, include = FALSE}
 library(reticulate)
 knitr::opts_chunk$set(cache=TRUE)
-knitr::knit_engines$set(python = eng_python)
-knitr::cache_engines$set(python = cache_eng_python)
 ```
 
 Cache can handle changes to second chunk:

tests/testthat/resources/eng-reticulate-cache-test.Rmd

@@ -25,9 +25,9 @@ test_that("An R Markdown document builds if a cache is modified", {
   old_var <- "1"
   new_var <- "0"
   mutate_chunk <- function(x) {
-    print_line <- 19
+    print_line <- 17
     file_text <- readLines("resources/eng-reticulate-cache-test.Rmd")
-    file_text[print_line] <- paste("print(x + ", x, ")", sep = "")
+    file_text[print_line] <- paste0("print(x + ", x, ")")
     writeLines(file_text, "resources/eng-reticulate-cache-test.Rmd")
   }
   mutate_chunk(old_var)