Remove GCS to lessen attack surface

r/R/arrow-info.R

@@ -140,7 +140,7 @@ some_features_are_off <- function(features) {
   # `features` is a named logical vector (as in arrow_info()$capabilities)
   # Let's exclude some less relevant ones
   # jemalloc is only included because it is sometimes disabled in our build process
-  blocklist <- c("lzo", "bz2", "brotli", "substrait", "jemalloc")
+  blocklist <- c("lzo", "bz2", "brotli", "substrait", "jemalloc", "gcs")
   # Return TRUE if any of the other features are FALSE
   !all(features[setdiff(names(features), blocklist)])
 }

r/tools/nixlibs.R

@@ -574,12 +574,12 @@ build_libarrow <- function(src_dir, dst_dir) {
         env_var_list <- c(env_var_list, setNames("BUNDLED", env_var))
       }
     }
-    # We also _do_ want to enable S3, GCS, and ZSTD by default
+    # We also _do_ want to enable S3 and ZSTD by default
     # so that binaries built on CRAN from source are fully featured
+    # but defer to the env vars if those are set
     env_var_list <- c(
       env_var_list,
       ARROW_S3 = Sys.getenv("ARROW_S3", "ON"),
-      ARROW_GCS = Sys.getenv("ARROW_GCS", "ON"),
       ARROW_WITH_ZSTD = Sys.getenv("ARROW_WITH_ZSTD", "ON")
     )
   }
@@ -822,14 +822,12 @@ set_thirdparty_urls <- function(env_var_list) {
   env_var_list
 }
 
+# this is generally about features that people asked for via environment variables, but
+# for some cases (like S3 when we override it in this script) we might find those in
+# env_var_list
 is_feature_requested <- function(env_varname, env_var_list, default = env_is("LIBARROW_MINIMAL", "false")) {
-  # look in our env_var_list first, if it's not found there go to
-  # the actual environment
-  env_value <- tolower(env_var_list[[env_varname]])
-  if (is.null(env_value)) {
-    env_value <- tolower(Sys.getenv(env_varname))
-  }
-
+  # look in the environment first, but then use the env_var_list if nothing is found
+  env_value <- tolower(Sys.getenv(env_varname, env_var_list[[env_varname]]))
   if (identical(env_value, "off")) {
     # If e.g. ARROW_MIMALLOC=OFF explicitly, override default
     requested <- FALSE