Ensure pak is installed to system library

Includes workaround for r-wasm/webr#422.

build-rwasm/Dockerfile

@@ -6,6 +6,10 @@ FROM $WEBR_IMAGE
 # Copies your code file from your action repository to the filesystem path `/` of the container
 COPY code.R /code.R
 
+# TODO: Remove this workaround for r-wasm/webr#422 when no longer needed
+RUN find /root/R/x86_64-pc-linux-gnu-library -maxdepth 2 -wholename '*/pak' -exec rm -rf {} \;
+RUN /opt/R/current/bin/R -q -e 'install.packages("pak", lib = .Library)'
+
 # Code file to execute when the docker container starts up (`entrypoint.sh`)
 ENTRYPOINT [ "Rscript" ]
 # ENTRYPOINT [ "/bin/bash", "-l", "-c" ]

build-rwasm/code.R

@@ -31,7 +31,6 @@ if (is.character(strip) && length(strip) == 1 && strip == "NULL") strip <- NULL
 cat("\nArgs:\n")
 str(list(image_path = image_path, repo_path = repo_path, packages = packages, strip = strip))
 
-if (!require("pak", character.only = TRUE, quietly = TRUE)) install.packages("pak")
 if (!require("withr", character.only = TRUE, quietly = TRUE)) install.packages("withr")
 
 # Work in the GHA directory so that package reference 'local::.' works as expected