initial draft

R/use_msrv.R

@@ -0,0 +1,54 @@
+#' Add MSRV to DESCRIPTION
+#' 
+#' @param version character scalar, the minimum supported Rust version
+#' @param path character scalar, path to folder containing DESCRIPTION file
+#' 
+#' @details
+#' It is assumed that MSRV is greater than or equal to `version`. The result is
+#' "SystemRequirements: Cargo (Rust's package manager), rustc >= `version`."
+#' 
+#' @return NULL
+#' @export
+#' 
+#' @examples
+#' \dontrun{
+#' use_msrv("1.67.1")
+#' }
+#' 
+use_msrv <- function(version = NULL, path = "."){
+
+  if (is.null(version)){
+    cli::cli_abort(
+      "Minimum supported Rust {.arg version} not specified.",
+      class = "rextendr_error"
+    )
+  }
+
+  desc_path <- rprojroot::find_package_root_file("DESCRIPTION", path = path)
+
+  if (!file.exists(desc_path)) {
+    cli::cli_abort(
+      "{.arg path} ({.path {path}}) does not contain a DESCRIPTION",
+      class = "rextendr_error"
+    )
+  }
+
+  cur <- paste("Cargo (Rust's package manager), rustc", paste(">=", version)) 
+
+  prev <- desc::desc_get("SystemRequirements", file = desc_path)[[1]]
+  prev <- stringi::stri_trim_both(prev)
+
+  if (is.na(prev)) {
+    update_description("SystemRequirements", cur, desc_path = desc_path)
+  } else if (!identical(cur, prev)) {
+    cli::cli_ul(
+      c(
+        "The SystemRequirements field in the {.file DESCRIPTION} file is already set.",
+        "Please update it manually if needed."
+      )
+    )
+  }
+
+  invisible(version)
+
+}