Travis CI-编织和依存关系

Question

我正在为我的CI软件包使用travis。我在R发行版和开发版本的Mac上遇到错误。这些是我得到的错误：

发行版：

Error in loadVignetteBuilder(pkgdir, TRUE) : 
  vignette builder 'knitr' not found
Execution halted
The command "R CMD build  ." failed and exited with 1 during .
Your build has been stopped.

开发版本：

Installing packages into ‘/Users/travis/R/Library’
(as ‘lib’ is unspecified)
Error: (converted from warning) unable to access index for repository https://cloud.r-project.org/bin/macosx/el-capitan/contrib/4.0:
  cannot open URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/4.0/PACKAGES'
Execution halted
The command "Rscript -e 'deps <- remotes::dev_package_deps(dependencies = NA);remotes::install_deps(dependencies = TRUE);if (!all(deps$package %in% installed.packages())) { message("missing: ", paste(setdiff(deps$package, installed.packages()), collapse=", ")); q(status = 1, save = "no")}'" failed and exited with 1 during .

关于发行版中的错误，我已在“ DESCRIPTION”文件中指定“建议：knitr和VignetteBuilder：knitr”。开发版本错误我不明白。似乎在TRAVIS上出错。

这些是travis yml文件中的设置：

language: R
sudo: false
cache: packages
warnings_are_errors: true

os:
  - linux
  - osx

r:
  - oldrel
  - release

有什么建议吗？

Answer 1

R需要安装knitr以生成软件包。也许您的基本环境中缺少此软件包（我不熟悉travis）。

您是否可以添加一个步骤来明确安装它，例如

R -e 'install.packages("knitr")'