Add support for imports field in standalone files

R/use-standalone.R

@@ -8,12 +8,49 @@
 #' It always overwrites an existing standalone file of the same name, making
 #' it easy to update previously imported code.
 #'
+#' @section Supported fields:
+#'
+
+#' A standalone file has YAML frontmatter that provides additional information,
+#' such as where the file originates from and when it was last updated. Here is
+#' an example:
+#'
+#' ```
+#' ---
+#' repo: r-lib/rlang
+#' file: standalone-types-check.R
+#' last-updated: 2023-03-07
+#' license: https://unlicense.org
+#' dependencies: standalone-obj-type.R
+#' imports: rlang (>= 1.1.0)
+#' ---
+#'
+#' Two of these fields are consulted by `use_standalone()`:
+#'
+#' - `dependencies`: A file or a list of files in the same repo that
+#'   the standalone file depends on. These files are retrieved
+#'   automatically by `use_standalone()`.
+#'
+#' - `imports`: A package or list of packages that the standalone file
+#'    depends on. A minimal version may be specified in parentheses,
+#'    e.g. `rlang (>= 1.0.0)`. These dependencies are passed to
+#'    [use_package()] to ensure they are included in the `Imports:`
+#'    field of the `DESCRIPTION` file.
+#'
+#' Note that lists are specified with standard YAML syntax, using
+#' square brackets, for example: `# imports: [rlang (>= 1.0.0), purrr]`.
+#'
 #' @inheritParams create_from_github
 #' @inheritParams use_github_file
 #' @param file Name of standalone file. The `standalone-` prefix and file
 #'   extension are optional. If omitted, will allow you to choose from the
 #'   standalone files offered by that repo.
 #' @export
+#' @examples
+#' \dontrun{
+#' use_standalone("r-lib/rlang", file = "types-check")
+#' use_standalone("r-lib/rlang", file = "types-check", ref = "standalone-dep")
+#' }
 use_standalone <- function(repo_spec, file = NULL, ref = NULL, host = NULL) {
   check_is_project()
 
@@ -42,8 +79,22 @@ use_standalone <- function(repo_spec, file = NULL, ref = NULL, host = NULL) {
   write_over(proj_path(dest_path), lines, overwrite = TRUE)
 
   dependencies <- standalone_dependencies(lines, path)
-  for (dependency in dependencies) {
-    use_standalone(repo_spec, dependency)
+
+  for (dependency in dependencies$deps) {
+    use_standalone(repo_spec, dependency, ref = ref, host = host)
+  }
+
+  imports <- dependencies$imports
+
+  for (i in seq_len(nrow(imports))) {
+    import <- imports[i, , drop = FALSE]
+
+    if (is.na(import$ver)) {
+      ver <- NULL
+    } else {
+      ver <- import$ver
+    }
+    use_package(import$pkg, min_version = ver)
   }
 
   invisible()
@@ -114,12 +165,79 @@ standalone_dependencies <- function(lines, path, error_call = caller_env()) {
   temp <- withr::local_tempfile(lines = header)
   yaml <- rmarkdown::yaml_front_matter(temp)
 
-  deps <- yaml$dependencies
-  if (!is.null(deps) && !is.character(deps)) {
+  as_chr_field <- function(field) {
+    if (!is.null(field) && !is.character(field)) {
+      cli::cli_abort(
+        "Invalid dependencies specification in {.path {path}}.",
+        call = error_call
+      )
+    }
+
+    field %||% character()
+  }
+
+  deps <- as_chr_field(yaml$dependencies)
+  imports <- as_chr_field(yaml$imports)
+  imports <- as_version_info(imports, error_call = error_call)
+
+  if (any(na.omit(imports$cmp) != ">=")) {
+    cli::cli_abort(
+      "Version specification must use {.code >=}.",
+      call = error_call
+    )
+  }
+
+  list(deps = deps, imports = imports)
+}
+
+as_version_info <- function(fields, error_call = caller_env()) {
+  if (!length(fields)) {
+    return(version_info_df())
+  }
+
+  if (any(grepl(",", fields))) {
+    msg <- c(
+      "Version field can't contain comma.",
+      "i" = "Do you need to wrap in a list?"
+    )
+    cli::cli_abort(msg, call = error_call)
+  }
+
+  info <- lapply(fields, as_version_info_row, error_call = error_call)
+  inject(rbind(!!!info))
+}
+
+as_version_info_row <- function(field, error_call = caller_env()) {
+  version_regex <- "(.*) \\((.*)\\)$"
+  has_ver <- grepl(version_regex, field)
+
+  if (!has_ver) {
+    return(version_info_df(field, NA, NA))
+  }
+
+  pkg <- sub(version_regex, "\\1", field)
+  ver <- sub(version_regex, "\\2", field)
+
+  ver <- strsplit(ver, " ")[[1]]
+
+  if (!is_character(ver, n = 2) || any(is.na(ver)) || !all(nzchar(ver))) {
     cli::cli_abort(
-      "Invalid dependencies specification in {.path {path}}.",
+      c(
+        "Can't parse version `{field}` in `imports:` field.",
+        "i" = "Example of expected version format: `rlang (>= 1.0.0)`."
+      ),
       call = error_call
     )
   }
-  deps %||% character()
+
+  version_info_df(pkg, ver[[1]], ver[[2]])
+}
+
+version_info_df <- function(pkg = chr(), cmp = chr(), ver = chr()) {
+  df <- data.frame(
+    pkg = as.character(pkg),
+    cmp = as.character(cmp),
+    ver = as.character(ver)
+  )
+  structure(df, class = c("tbl", "data.frame"))
 }

R/utils.R

@@ -114,3 +114,8 @@ maybe_string <- function(x, nm = deparse(substitute(x))) {
     check_string(x, nm = nm)
   }
 }
+
+# For stability of `stringsAsFactors` across versions
+data.frame <- function(..., stringsAsFactors = FALSE) {
+  base::data.frame(..., stringsAsFactors = stringsAsFactors)
+}

tests/testthat/_snaps/use-standalone.md

@@ -22,6 +22,26 @@
       [3] "# ----------------------------------------------------------------------"  
       [4] "#"                                                                         
 
+# can extract imports
+
+    Code
+      extract_imports("# imports: rlang (== 1.0.0)")
+    Condition
+      Error in `extract_imports()`:
+      ! Version specification must use `>=`.
+    Code
+      extract_imports("# imports: rlang (>= 1.0.0), purrr")
+    Condition
+      Error in `extract_imports()`:
+      ! Version field can't contain comma.
+      i Do you need to wrap in a list?
+    Code
+      extract_imports("# imports: foo (>=0.0.0)")
+    Condition
+      Error in `extract_imports()`:
+      ! Can't parse version `foo (>=0.0.0)` in `imports:` field.
+      i Example of expected version format: `rlang (>= 1.0.0)`.
+
 # errors on malformed dependencies
 
     Code

tests/testthat/test-use-standalone.R

@@ -2,11 +2,16 @@ test_that("can import standalone file with dependencies", {
   skip_if_offline()
   create_local_package()
 
-  use_standalone("r-lib/rlang", "types-check", ref = "4670cb233ecc8d11")
+  # NOTE: Check ref after r-lib/rlang@standalone-dep has been merged
+  use_standalone("r-lib/rlang", "types-check", ref = "73182fe94")
   expect_setequal(
     as.character(path_rel(dir_ls(proj_path("R"))), proj_path()),
     c("R/import-standalone-types-check.R", "R/import-standalone-obj-type.R")
   )
+
+  desc <- proj_desc()
+  imports <- proj_desc()$get_field("Imports")
+  expect_true(grepl("rlang \\(", imports))
 })
 
 test_that("can use full github url", {
@@ -40,14 +45,52 @@ test_that("header provides useful summary", {
 
 test_that("can extract dependencies", {
   extract_deps <- function(deps) {
-    standalone_dependencies(c("# ---", deps, "# ---"), "test.R")
+    out <- standalone_dependencies(c("# ---", deps, "# ---"), "test.R")
+    out$deps
   }
 
   expect_equal(extract_deps(NULL), character())
   expect_equal(extract_deps("# dependencies: a"), "a")
   expect_equal(extract_deps("# dependencies: [a, b]"), c("a", "b"))
 })
 
+test_that("can extract imports", {
+  extract_imports <- function(imports) {
+    out <- standalone_dependencies(
+      c("# ---", imports, "# ---"),
+      "test.R",
+      error_call = current_env()
+    )
+    out$imports
+  }
+
+  expect_equal(
+    extract_imports(NULL),
+    version_info_df()
+  )
+
+  expect_equal(
+    extract_imports("# imports: rlang"),
+    version_info_df("rlang", NA, NA)
+  )
+
+  expect_equal(
+    extract_imports("# imports: rlang (>= 1.0.0)"),
+    version_info_df("rlang", ">=", "1.0.0")
+  )
+
+  expect_equal(
+    extract_imports("# imports: [rlang (>= 1.0.0), purrr]"),
+    version_info_df(c("rlang", "purrr"), c(">=", NA), c("1.0.0", NA))
+  )
+
+  expect_snapshot(error = TRUE, {
+    extract_imports("# imports: rlang (== 1.0.0)")
+    extract_imports("# imports: rlang (>= 1.0.0), purrr")
+    extract_imports("# imports: foo (>=0.0.0)")
+  })
+})
+
 test_that("errors on malformed dependencies", {
   expect_snapshot(error = TRUE, {
     standalone_dependencies(c(), "test.R")