kranc: Don't rely on Mathematica exit code for detecting failure

When no licence is available, Mathematica still exits with a zero exit code.  This causes dependency-based systems such as Make to assume that the thorn was created successfully, when it might not have been.  To work around this, we perform a file operation (deleting a temporary directory) from within Mathematica, and check that this was successful after Mathematica finishes, and adjust the exit code of the script accordingly.

Fixes Issue #39.

1 files changed, 24 insertions, 1 deletions

diff --git a/Bin/kranc b/Bin/kranc
index e82e75a..dafc76c 100755
--- a/Bin/kranc
+++ b/Bin/kranc
@@ -48,4 +48,27 @@ else
     exit 1
 fi
 
-$MATH -run "Get[\"$KRANCDIR/Tools/MathematicaMisc/RunKranc.m\"]" $MMASCRIPT </dev/null
+# If there is no licence server, Mathematica still exits with a 0 exit
+# code. In order to catch this error and exit with a nonzero code, we
+# first create a temporary directory, then remove it from within
+# Mathematica, then check to see that this happened.  If it didn't, we
+# assume there was some problem with launching Mathematica.
+
+flagdir="kranc.tmp.$$" # mktemp is not the same on Linux and Mac OS; here we assume we can write to the current directory
+mkdir $flagdir
+
+if $MATH -run "DeleteDirectory[\"$flagdir\"]; Get[\"$KRANCDIR/Tools/MathematicaMisc/RunKranc.m\"]" $MMASCRIPT </dev/null; then
+    if [ ! -d "$flagdir" ]; then
+        # Mathematica kernel started and executed DeleteDirectory
+        exit 0
+    else
+        echo "Mathematica did not start successfully"
+        rmdir "$flagdir"
+        exit 1
+    fi
+else
+    if [ -d "$flagdir" ]; then
+         rmdir "$flagdir"
+         exit 1
+    fi
+fi