Improve cross-compiling w/o native deps

We now install dummy versions of the dependencies
when cross-compiling, so native dependencies are
not needed. This fixes compilation on PPM.

[ci skip]

Author: gaborcsardi

src/dummy/cli/DESCRIPTION

@@ -0,0 +1,2 @@
+Package: cli
+Version: 100.0.0

src/dummy/cli/NAMESPACE

@@ -0,0 +1,2 @@
+Package: curl
+Version: 100.0.0

src/dummy/curl/DESCRIPTION

@@ -0,0 +1,2 @@
+Package: desc
+Version: 100.0.0

src/dummy/curl/NAMESPACE

@@ -0,0 +1,2 @@
+Package: filelock
+Version: 100.0.0

src/dummy/desc/DESCRIPTION

@@ -0,0 +1,2 @@
+Package: jsonlite
+Version: 100.0.0

src/dummy/desc/NAMESPACE

@@ -0,0 +1,2 @@
+Package: lpSolve
+Version: 100.0.0

src/dummy/filelock/DESCRIPTION

@@ -0,0 +1,2 @@
+Package: pkgbuild
+Version: 100.0.0

src/dummy/filelock/NAMESPACE

@@ -0,0 +1,2 @@
+Package: pkgcache
+Version: 100.0.0

src/dummy/jsonlite/DESCRIPTION

@@ -0,0 +1,2 @@
+Package: ps
+Version: 100.0.0

src/dummy/jsonlite/NAMESPACE

@@ -0,0 +1,2 @@
+Package: zip
+Version: 100.0.0

src/dummy/lpSolve/DESCRIPTION

@@ -96,15 +96,89 @@ install_order <- function() {
   pkgs
 }
 
+install_dummies <- function(lib) {
+  pkgs <- dir("dummy")
+  dir.create(lib, showWarnings = FALSE, recursive = TRUE)
+  on.exit(Sys.unsetenv("PAK_INSTALL_DUMMY_CROSS"), add = TRUE)
+  Sys.setenv(PAK_INSTALL_DUMMY_CROSS = "true")
+  message("Dummy packages")
+  for (pkg in pkgs) {
+    install.packages(
+      paste0("dummy/", pkg),
+      lib = lib,
+      repos = NULL,
+      type = "source",
+      INSTALL_opts = opts()
+    )
+    if (!file.exists(file.path(lib, pkg))) {
+      stop("Failed to install dummy ", pkg)
+    }
+  }
+
+  # need real R6
+  message("Real R6")
+  install.packages(
+    "library/R6",
+    lib = lib,
+    repos = NULL,
+    type = "source",
+    INSTALL_opts = opts()
+  )
+  if (!file.exists(file.path(lib, "R6"))) {
+    stop("Failed to install dummy R6")
+  }
+
+  # real processx
+  message("Real-ish processx")
+  install.packages(
+    "library/processx",
+    lib = lib,
+    repos = NULL,
+    type = "source",
+    INSTALL_opts = c(opts(), "--no-libs")
+  )
+  if (!file.exists(file.path(lib, "processx"))) {
+    stop("Failed to install dummy processx")
+  }
+  nspath <- file.path(lib, "processx", "NAMESPACE")
+  ns <- readLines(nspath)
+  ns2 <- grep("useDynLib", ns, invert = TRUE, value = TRUE)
+  writeLines(ns2, nspath)
+  nsipath <- file.path(lib, "processx", "Meta", "nsInfo.rds")
+  nsi <- readRDS(nsipath)
+  nsi$dynlibs <- character()
+  saveRDS(nsi, nsipath)
+
+  # real callr
+  message("Real-ish callr")
+  install.packages(
+    "library/callr",
+    lib = lib,
+    repos = NULL,
+    type = "source",
+    INSTALL_opts = opts()
+  )
+  if (!file.exists(file.path(lib, "callr"))) {
+    stop("Failed to install dummy callr")
+  }
+}
+
 install_all <- function(lib = NULL) {
   pkgs <- install_order()
   if (Sys.getenv("CROSS_COMPILING") == "yes") {
+    # create dummy library
+    lib <- get_lib(lib)
+    dummy <- paste0(lib, "-dummy")
+    .libPaths(c(dummy, .libPaths()))
+    Sys.setenv(R_LIBS_USER = dummy)
+    print(Sys.getenv("R_LIBS_USER"))
+    install_dummies(lib = dummy)
+
     # Update 'Built' field in package itself
     update_description_build(
       Sys.getenv("R_PACKAGE_DIR"),
       Sys.getenv("R_TARGET_PLATFORM")
     )
-    lib <- get_lib(lib)
     for (pkg in pkgs) {
       install_one(pkg, lib = paste0(lib, "-", pkg))
     }

src/dummy/lpSolve/NAMESPACE

@@ -0,0 +1,41 @@
+diff --git a/src/library/processx/R/client-lib.R b/src/library/processx/R/client-lib.R
+index ab77dfa6..3eefd93a 100644
+--- a/src/library/processx/R/client-lib.R
++++ b/src/library/processx/R/client-lib.R
+@@ -1,6 +1,8 @@
+ 
+ client <- new.env(parent = emptyenv())
+ 
++if (Sys.getenv("PAK_INSTALL_DUMMY_CROSS") != "true") {
++
+ local({
+   ext <- .Platform$dynlib.ext
+   arch <- .Platform$r_arch
+@@ -47,6 +49,8 @@ local({
+   }
+ })
+ 
++}
++
+ # This is really only here for testing
+ 
+ load_client_lib <- function(client) {
+diff --git a/src/library/processx/R/on-load.R b/src/library/processx/R/on-load.R
+index 6ade28dd..eca25dc3 100644
+--- a/src/library/processx/R/on-load.R
++++ b/src/library/processx/R/on-load.R
+@@ -1,6 +1,8 @@
+ 
+ ## nocov start
+ 
++if (Sys.getenv("PAK_INSTALL_DUMMY_CROSS") != "true") {
++
+ .onLoad <- function(libname, pkgname) {
+   ## This is needed to fix the boot time to a given value,
+   ## because in a Docker container (maybe elsewhere as well?) on
+@@ -26,4 +28,5 @@
+   supervisor_reset()
+ }
+ 
++}
+ ## nocov end

src/dummy/pkgbuild/DESCRIPTION

@@ -1,6 +1,8 @@
 
 client <- new.env(parent = emptyenv())
 
+if (Sys.getenv("PAK_INSTALL_DUMMY_CROSS") != "true") {
+
 local({
   ext <- .Platform$dynlib.ext
   arch <- .Platform$r_arch
@@ -47,6 +49,8 @@ local({
   }
 })
 
+}
+
 # This is really only here for testing
 
 load_client_lib <- function(client) {

src/dummy/pkgbuild/NAMESPACE

@@ -1,6 +1,8 @@
 
 ## nocov start
 
+if (Sys.getenv("PAK_INSTALL_DUMMY_CROSS") != "true") {
+
 .onLoad <- function(libname, pkgname) {
   ## This is needed to fix the boot time to a given value,
   ## because in a Docker container (maybe elsewhere as well?) on
@@ -26,4 +28,5 @@
   supervisor_reset()
 }
 
+}
 ## nocov end

src/dummy/pkgcache/DESCRIPTION

@@ -16,7 +16,9 @@ WORKDIR /root
 
 # need to install the native package first --------------------------------
 
-# TODO: aboid this, by using dummy packages.
+# this is not needed for the cross-compilation, but it is easier to use
+# the native package for deployment, as long as the deploy code is
+# inside the pak package itself.
 
 COPY pak_*.tar.gz /root/
 

src/dummy/pkgcache/NAMESPACE

@@ -45,6 +45,8 @@ export PKGFILES := $(patsubst %,lib/%/pak_$(PAKVERSION).tgz,$(RVERSIONS))
 
 deploy:
 	@echo "----- DEPLOYING packages -----------------------------------"
+	# this is somewhat redundant, but needed when cross-compiling, to have
+	# a native package installed.
 	$(R) CMD INSTALL pak_$(PAKVERSION).tar.gz
 	R_LIBS=$(RLIB) $(R) -q -e 'pak::pkg_install("deps::$(PKGROOT)", dependencies = "Config/Needs/deploy")'
 	R_LIBS=$(RLIB) $(R) -q -e \

src/dummy/ps/DESCRIPTION

@@ -31,18 +31,9 @@ fi
 
 echo "Cross compiling for R ${RVER} using R ${RVERX86}."
 
-# Need to install all dependencies for the build arch first.
-# TODO: look up the needed packages automatically
-# TODO: should make sure the right versions are installed
-
-R_MAKEVARS_USER="`pwd`/Makevars-macos-${RVERX86}" \
-    R_COMPILE_AND_INSTALL_PACKAGES=always \
-    "/usr/local/bin/R-${RVERX86}" -q \
-    -e 'install.packages(c("pkgdepends", "pkgsearch"))'
-
-# TODO: we will need to hsve R-version specific platform triplets,
+# TODO: we will need to have R-version specific platform triplets,
 # when a version of R starts using a newer build than the current
-# Big Sur (darwin 20).
+# Big Sur (darwin 20). (Maybe?)
 
 R_MAKEVARS_USER="`pwd`/Makevars-macos-${RVER}" \
     "/usr/local/bin/R-${RVERX86}" CMD INSTALL \