single-option setter does not modify other options

fixes #655

NEWS.md

@@ -13,6 +13,9 @@
   repository. Improves cache reuse for packages originally installed by
   `remotes<2.0.2`. (#652)
 
+- The `packrat::opts` single-option setter no longer overwrites previously
+  written state. (#655)
+
 # Packrat 0.7.0
 
 - Fixed an issue where Packrat could inadvertently execute non-R code chunks

R/options.R

@@ -173,8 +173,13 @@ get_opts <- function(options = NULL, simplify = TRUE, project = NULL) {
 make_setter <- function(name) {
   force(name)
   function(x, persist = TRUE) {
-    if (missing(x)) return(get_opts(name))
-    else setOptions(setNames(list(x), name), persist = persist)
+    if (missing(x)) {
+      return(get_opts(name))
+    } else {
+      o <- get_opts()
+      o[[name]] <- x
+      setOptions(o, persist = persist)
+    }
   }
 }
 

tests/testthat/test-options.R

@@ -0,0 +1,15 @@
+# Confirms that we can use set_opts and the single-option setter and that the
+# single-option setter does not overwrite previously configured state (#655)
+test_that("an option can be set and retrieved", {
+  initial <- get_opts()
+
+  expected <- initial
+  expected[["ignored.packages"]] <- c("emo")
+  expected[["snapshot.recommended.packages"]] <- TRUE
+
+  packrat::set_opts(ignored.packages = c("emo"), persist = FALSE)
+  packrat::opts$snapshot.recommended.packages(TRUE, persist = FALSE)
+
+  actual <- get_opts()
+  expect_equal(actual, expected)
+})