Recompile if `.o` and `.so` are from a different arch or R version

[gaborcsardi]

So that pkgload::load_all() recompiles in this case.

[DavisVaughan]

See also https://github.com/r-lib/pkgload/issues/226

[DavisVaughan]

Random thought to use otool on mac? Could compare R version seen here with current R version!

r_version_last_compiled_on <- function(package, dir) {
  # find `.so` file
  dir <- file.path(dir, "src", paste0(package, ".so"))

  # get libraries used
  result <- processx::run(
    "otool", 
    args = c("-L", dir)
  )

  if (result$status != 0L) {
    # Don't know, process failed, say no.
    return(FALSE)
  }
  if (length(result$stdout) == 0L) {
    return(FALSE)
  }

  # here is what this looks like
  cat("The stdout:\n")
  cat(result$stdout)
  cat("\n")

  lines <- strsplit(result$stdout, "\n")[[1L]]
  line <- lines[grepl("libR.dylib", lines, fixed = TRUE)]

  if (length(line) != 1L) {
    return(FALSE)
  }

  match <- stringr::str_match(
    line, 
    "current version ([0|[1-9]\\d*]\\.[0|[1-9]\\d*]\\.0|[1-9]\\d*])"
  )

  if (nrow(match) != 1L || ncol(match) != 2L) {
    return(FALSE)
  }

  match[[1L, 2L]]
}

package <- "rlang"
dir <- getwd()

r_version_last_compiled_on(package, dir)

The stdout:
/Users/davis/files/r/packages/rlang/src/rlang.so:
    rlang.so (compatibility version 0.0.0, current version 0.0.0)
    /Library/Frameworks/R.framework/Versions/4.5/Resources/lib/libR.dylib (compatibility version 4.5.0, current version 4.5.0)
    /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 2202.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1336.61.1)

[1] "4.5.0"