MINOR: [R] Avoid stray output from expr when checking for 10.13 (#38303)

### Rationale for this change `expr` was printing the number of matching chars which showed up as noise in the log (which we want to avoid as much as possible to avoid any false positive checks) See #38236 (comment) for @ jonkeane's investigation. ### What changes are included in this PR? Replace use of expr with test. ### Are these changes tested? Crossbow Lead-authored-by: Jacob Wujciak-Jens <[email protected]> Co-authored-by: Jonathan Keane <[email protected]> Signed-off-by: Jonathan Keane <[email protected]>
apache · Oct 17, 2023 · 40571db · 40571db
1 parent a5043e7
commit 40571db
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/r/configure b/r/configure
@@ -264,7 +264,10 @@ set_pkg_vars () {
     PKG_CFLAGS="$PKG_CFLAGS $ARROW_R_CXXFLAGS"
   fi
 
-  if [ "$UNAME" = "Darwin" ] && expr $(sw_vers -productVersion) : '10\.13'; then
+  # We use expr because the product version returns more than just 10.13 and we want to 
+  # match the substring. However, expr always outputs the number of matched characters
+  # to stdout, to avoid noise in the log we redirect the output to /dev/null
+  if [ "$UNAME" = "Darwin" ] && expr $(sw_vers -productVersion) : '10\.13' >/dev/null 2>&1; then
     # avoid C++17 availability warnings on macOS < 11
     PKG_CFLAGS="$PKG_CFLAGS -D_LIBCPP_DISABLE_AVAILABILITY"
   fi