Make ignore() work inside special functions

loadd(), readd(), file_in(), file_out(), knitr_in()

NEWS.md

@@ -18,6 +18,7 @@ These changes are technically breaking changes, but they should only affect adva
 - Repair `expose_imports()`: do not do the `environment<-` trick unless the object is a non-primitive function.
 - Use different static analyses of `assign()` vs `delayedAssign()`.
 - Fix a superfluous code analysis warning incurred by multiple `file_in()` files and other strings ([#896](https://github.com/ropensci/drake/issues/896)).
+- Make `ignore()` work inside `loadd()`, `readd()`, `file_in()`, `file_out()`, and `knitr_in()`.
 
 ## New features
 

R/api-read.R

@@ -26,10 +26,20 @@
 #'   and then treat those loaded targets as dependencies.
 #'   That way, [make()] will automatically (re)run the report if those
 #'   dependencies change.
-#' @note Please do not put calls to [loadd()] or [readd()] inside
-#' your custom (imported) functions or the commands in your [drake_plan()].
-#' This creates confusion inside [make()], which has its own ways of
-#' interacting with the cache.
+#' 3. If you are using `make(memory_strategy = "none")`
+#'   or `make(memory_strategy = "unload")`,
+#'   [loadd()] and [readd()] can manually load dependencies
+#'   into memory for the target that is being built.
+#'   If you do this, you must carefully inspect [deps_target()]
+#'   and [vis_drake_graph()] before running [make()]
+#'   to be sure the dependency relationships among targets
+#'   are correct. If you do not wish to incur extra dependencies
+#'   with [loadd()] or [readd()], you will need to use [ignore()],
+#'   e.g. `drake_plan(x = 1, y = ignore(readd(x)))` or
+#'   `drake_plan(x = 1, y = readd(ignore("x"), character_only = TRUE))`.
+#'   Compare those plans to `drake_plan(x = 1, y = readd(x))`
+#'   and `drake_plan(x = 1, y = readd("x", character_only = TRUE))`
+#'   using [vis_drake_graph()] and [deps_target()].
 #' @seealso [cached()], [drake_plan()], [make()]
 #' @export
 #' @return The cached value of the `target`.

R/preprocess-codeanalysis.R

@@ -98,6 +98,7 @@ analyze_delayed_assign <- function(expr, results, locals, allowed_globals) {
 }
 
 analyze_loadd <- function(expr, results) {
+  expr <- ignore_ignore(expr)
   expr <- match.call(drake::loadd, as.call(expr))
   expr <- expr[-1]
   ht_set(results$loadd, analyze_strings(expr["list"]))
@@ -110,26 +111,30 @@ analyze_loadd <- function(expr, results) {
 }
 
 analyze_readd <- function(expr, results, allowed_globals) {
+  expr <- ignore_ignore(expr)
   expr <- match.call(drake::readd, as.call(expr))
   ht_set(results$readd, analyze_strings(expr["target"]))
   ht_set(results$readd, safe_all_vars(expr["target"]))
 }
 
 analyze_file_in <- function(expr, results) {
+  expr <- ignore_ignore(expr)
   x <- analyze_strings(expr[-1])
   x <- file.path(x)
   x <- encode_path(x)
   ht_set(results$file_in, x)
 }
 
 analyze_file_out <- function(expr, results) {
+  expr <- ignore_ignore(expr)
   x <- analyze_strings(expr[-1])
   x <- file.path(x)
   x <- encode_path(x)
   ht_set(results$file_out, x)
 }
 
 analyze_knitr_in <- function(expr, results) {
+  expr <- ignore_ignore(expr)
   files <- analyze_strings(expr[-1])
   lapply(files, analyze_knitr_file, results = results)
   ht_set(results$knitr_in, encode_path(files))

tests/testthat/test-dependencies.R

@@ -470,3 +470,46 @@ test_with_dir("ignore() in imported functions", {
   config <- drake_config(plan, cache = cache)
   expect_equal(justbuilt(config), "x")
 })
+
+test_with_dir("ignore() inside special functions", {
+  plan <- drake_plan(
+    a = 1,
+    b1 = readd(a),
+    b2 = readd("a"),
+    b3 = ignore(readd(a)),
+    b4 = readd(ignore(a)),
+    b5 = readd(ignore("a")),
+    c1 = loadd(a),
+    c2 = loadd("a"),
+    c3 = ignore(loadd(a)),
+    c4 = loadd(ignore(a)),
+    c5 = loadd(ignore("a")),
+    d1 = file_in("a"),
+    d2 = file_in("a"),
+    d3 = ignore(file_in("a")),
+    d4 = file_in(ignore("a")),
+    d5 = file_in(ignore("a")),
+    e1 = file_out("a"),
+    e2 = file_out("a"),
+    e3 = ignore(file_out("a")),
+    e4 = file_out(ignore("a")),
+    e5 = file_out(ignore("a")),
+    f1 = knitr_in("a"),
+    f2 = knitr_in("a"),
+    f3 = ignore(knitr_in("a")),
+    f4 = knitr_in(ignore("a")),
+    f5 = knitr_in(ignore("a"))
+  )
+  suppressWarnings(config <- drake_config(plan))
+  for (x in letters[2:6]) {
+    for (y in 1:5) {
+      target <- paste0(x, y)
+      deps <- deps_target(target, config, character_only = TRUE)$name
+      if (y < 3) {
+        expect_equal(deps, "a")
+      } else {
+        expect_equal(deps, character(0))
+      }
+    }
+  }
+})