no longer use require() in low-level code needing namespace

git-svn-id: https://svn.r-project.org/R/trunk@87247 00db46b3-68df-0310-9c12-caf00c1e9a41

doc/NEWS.Rd

@@ -103,6 +103,13 @@
  convert row names used for indexing using \code{I()}, which will
  lead to faster execution in cases where \code{sort = TRUE} and
  \code{all.x} and/or \code{all.y} are set to \code{TRUE}.
+
+ \item \pkg{methods} package internal \code{.requirePackage()} now
+ calls \code{requireNamespace(p)} instead of \code{require(p)}, hence
+ no longer adding packages to the \code{search()} path in cases
+ methods or class definitions are needed. Consequently, previous
+ workflows relying on the old behaviour will have to be amended by
+ adding corresponding \code{library(p)} calls.
  }
  }
 

src/library/methods/R/RClassUtils.R

@@ -1807,46 +1807,41 @@ substituteFunctionArgs <-
 
 ## bootstrap version: all classes and methods must be in the version of the methods
 ## package being built in the toplevel environment: MUST avoid require("methods") !
-.requirePackage <- function(package, mustFind = TRUE)
+.requirePackage <- function(package, mustFind = TRUE, quietly = FALSE)
  topenv(parent.frame())
 
 ## real version of .requirePackage
-..requirePackage <- function(package, mustFind = TRUE) {
- value <- package
+..requirePackage <- function(package, mustFind = TRUE, quietly = FALSE) {
  if(nzchar(package)) {
  ## lookup as lightning fast as possible:
- if (.Internal(exists(package, .Internal(getNamespaceRegistry()),
- "any", FALSE)))
- value <- getNamespace(package)
+ if(!is.null(ns <-.Internal(getRegisteredNamespace(package))))
+ return(ns)
  else {
  if(identical(package, ".GlobalEnv"))
  return(.GlobalEnv)
  if(identical(package, "methods"))
  return(topenv(parent.frame())) # booting methods
+ ## else continue
  }
  }
- if(is.environment(value))
- return(value)
- topEnv <- getOption("topLevelEnvironment")
- if(is.null(topEnv))
- topEnv <- .GlobalEnv
+ topEnv <- getOption("topLevelEnvironment", default = .GlobalEnv)
  if(!is.null(pkgN <- get0(".packageName", topEnv, inherits=TRUE)) &&
  .identC(package, pkgN))
  return(topEnv) # kludge for source'ing package code
+
  ## If called from .findInheritedMethods which disables S4 primitive dispatch,
  ## allow it here, as namespace loading hooks may need it:
  if(!.allowPrimitiveMethods(TRUE))
  on.exit(.allowPrimitiveMethods(FALSE))
- if(nzchar(package) && require(package, character.only = TRUE)) {}
+ if(nzchar(package) && requireNamespace(package, quietly=quietly))
+ getNamespace(package)
  else {
  if(mustFind)
  stop(gettextf("unable to load required package %s",
  sQuote(package)),
  domain = NA)
- else
- return(NULL)
  }
- getNamespace(package)
+ ## else return(NULL)
 }
 
 .classDefEnv <- function(classDef) {