Handle hard dependencies in library()

depend.R

depend <- function(..., character.only = FALSE) {
  # Mimic library()'s UI
  if (character.only) {
    packages <- c(...)
  } else {
    packages <- substitute(c(...))[-1]
    if (!all(vapply(packages, is.symbol, logical(1)))) {
      stop("Can't supply expressions if `character.only` is FALSE")
    }
    packages <- as.character(packages)
  }
  stopifnot(is.character(packages))

  lapply(packages, library, character.only = TRUE)

  packages <- paste0("package:", packages)
  packages <- unique(c(globalenv()$.__deps__., packages))
  assign(".__deps__.", packages, envir = globalenv())

  invisible(NULL)
}

library <- function(package, help, pos = 2, lib.loc = NULL,
                    character.only = FALSE, logical.return = FALSE,
                    warn.conflicts = TRUE, quietly = FALSE,
                    verbose = getOption("verbose")) {
  deps <- globalenv()$.__deps__.

  # Some ugliness to work around the fact that library() quotes some
  # of its arguments
  library_call <- sys.call()
  library_call[[1]] <- quote(base::library)

  # No deps, forward to base::library()
  if (is.null(deps)) {
    return(eval(library_call, parent.frame()))
  }

  if (!character.only) {
    package <- as.character(substitute(package))
  }
  stopifnot(is.character(package), length(package) == 1)

  positions <- match(deps, search())

  if (anyNA(positions)) {
    stop("Can't find dependency on the search path!")
  }

  library_call$pos <- max(positions) + 1L
  eval(library_call, parent.frame())
}


depend(stats, graphics)
library(dplyr)
#> Attaching package: ‘dplyr’
#>
#> The following objects are masked _by_ ‘package:stats’:
#>
#>     filter, lag
#>
#> The following objects are masked from ‘package:base’:
#>
#>     intersect, setdiff, setequal, union