在需要/加载软件包后，是否可以覆盖阻止软件包的重新安装? [英] Possible to override the blocking of a package's (re-)installation after it has been required/loaded?

问题描述

是否有可能在需要/加载软件包后覆盖对软件包(重新)安装的阻止?

Is it possible to override the blocking of a package's (re-)installation after it has been required/loaded?

我了解到，一旦使用了软件包，阻止对加载软件包的相同库进行真正的" 重新安装是很有意义的.但是我的用例有些不同

I understand that blocking a "true" re-installation to the same library that the package was loaded from makes perfect sense once the package is in use. But my use case is a bit different

我喜欢使用沙盒库"来测试自己的程序包的想法.除了要测试的软件包之外，这些沙箱库还包含干净基础R安装的所有基本软件包 plus ，这些contrib软件包对于使我的整个软件包构建和测试框架正常工作是必需的(例如，stringr等).但是，我的框架从标准库加载了后一个程序包，然后然后需要将它们安装到沙箱库中-该库被阻止了.因此，我的问题是是否有可能将其覆盖，因为我并没有真正实现人们在实现该块时的想法.

I like the idea of having a "sandbox library" to test own packages. Besides the package(s) to test, those sandbox libraries contain all base packages of a clean base R installation plus some contrib packages necessary in order for my whole package building and testing framework to work (e.g. digest, stringr etc.). However, my framework loads the latter packages from the standard lib and then needs to install them to the sandbox lib - which is blocked. Hence my question if it is possible to override this as I'm not really doing what people had in mind when implementing the block.

指定两个库的路径

lib         <- file.path(R.home(), "library")
lib.sandbox <- file.path(tempdir(), "library")

创建沙箱库

dir.create(lib.sandbox, showWarnings=FALSE)

将软件包安装到标准库中并加载

Install a package to the standard library and load it

install.packages("digest", lib=lib)
require("digest", lib.loc=lib)

然后还将其安装到沙箱库中

Then also install it to the sandbox library

> install.packages("digest", lib=lib.sandbox)
Warning: package 'digest' is in use and will not be installed

我的框架 之后也加载了一些应该安装到沙箱库中的软件包，因此我无法将"install-to-sandbox-lib"步骤放在初始加载步骤.

My framework figures certain stuff out after certain packages that should also be installed to the sandbox lib are loaded, so I can't put the "install-to-sandbox-lib" step before the initial loading step.

推荐答案

以下是您在答案中建议的一般版本.这将在安装之前先卸载软件包，然后再从同一位置重新加载软件包.

Here's a general version of what you suggest in your answer. This will unload the package before installing and reload the package from the same location afterward.

install.packages.sandbox <- function(pkgs, lib, repos=getOption("repos"), ...) {
    if (is.null(repos)) 
        stop("Can't install from source. Need package name.")
    pkg.pos <- grep(pkgs, search())
    pkg.path <- searchpaths()[grep(pkgs, searchpaths())]
    in.use <- length(pkg.pos) > 0
    # detach
    if (in.use) do.call(detach, 
                  list(pkg.pos), 
                  envir=.GlobalEnv)
    # install
    utils::install.packages(pkgs, lib, repos, ...)
    # re-attach from original library location
    if (in.use) library(pkgs, 
                  character.only=TRUE, 
                  lib.loc=.libPaths()[sapply(.libPaths(), grepl, pkg.path)])
}

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