check for attrpath version compatibility

protects against problems caused by #24

check-attrpath-version.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+ATTR_PATH=$1
+NEW_VERSION=$2
+
+ATTR_VERSION_PART=$(echo "$ATTR_PATH" | sed -n 's/^[^0-9]*\([0-9_]*\)$/\1/p')
+
+# If we don't find version numbers in the attr path, exit success.
+if [ -z "$ATTR_VERSION_PART" ]
+then
+    exit 0
+fi
+
+# Check assuming version part has underscore separators
+ATTR_VERSION_PERIODS=$(echo "$ATTR_VERSION_PART" | sed -n 's/_/\./gp')
+
+if [ -n "$ATTR_VERSION_PERIODS" ]
+then
+   if [[ "$NEW_VERSION" == $ATTR_VERSION_PERIODS* ]]
+   then
+       exit 0
+   fi
+fi
+
+# Check assuming version part is the prefix of the version with dots
+# removed. For example, 91 => "9.1"
+NO_PERIOD_NEW_VERSION=$(echo "$NEW_VERSION" | sed -n 's/\.//gp')
+
+if [ -n "$NO_PERIOD_NEW_VERSION" ]
+then
+    if [[ "$NO_PERIOD_NEW_VERSION" == $ATTR_VERSION_PART* ]]
+    then
+        exit 0
+    fi
+fi
+
+exit 1

up.sh

@@ -133,6 +133,8 @@ then
     error_exit "Derivation contains buildPerlPackage."
 fi
 
+$("$SCRIPT_DIR"/check-attrpath-version.sh "$ATTR_PATH" "$NEW_VERSION") || error_exit "$ATTR_PATH version not compatible with $NEW_VERSION"
+
 # Make sure it hasn't been updated on master
 grep "$OLD_VERSION" "$DERIVATION_FILE" || error_exit "Old version not present in master derivation file."