Add a script that tests for SemVer version bumps

This will help us avoid cutting releases with unexpected or invalid
version increments.

Author: ctrueden

valid-semver-bump.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+
+# This script tests whether a given version bump is valid.
+
+die() {
+	echo "$*" >&2
+	exit 1
+}
+
+succeed() {
+	echo "$*" >&2
+	exit 0
+}
+
+major() {
+	major=${1%%.*}
+	test -n "$major" || die "Invalid SemVer: $1"
+	echo $major
+}
+
+minor() {
+	tmp=${1#*.}
+	minor=${tmp%%.*}
+	test -n "$minor" || die "Invalid SemVer: $1"
+	echo $minor
+}
+
+patch() {
+	patch=${1##*.}
+	test -n "$patch" || die "Invalid SemVer: $1"
+	echo $patch
+}
+
+SNAPSHOT="${1%-SNAPSHOT}"
+RELEASE="$2"
+
+test -n "$RELEASE" -a -n "$SNAPSHOT" ||
+	die "Usage: valid-semver-bump.sh previous-snapshot-version new-release-version"
+
+test "$RELEASE" = "$SNAPSHOT" &&
+	succeed "Detected DEFAULT version bump"
+
+NEW_MAJOR=$(major $RELEASE)
+NEW_MINOR=$(minor $RELEASE)
+NEW_PATCH=$(patch $RELEASE)
+OLD_MAJOR=$(major $SNAPSHOT)
+OLD_MINOR=$(minor $SNAPSHOT)
+OLD_PATCH=$(patch $SNAPSHOT)
+
+# check for MINOR version bump
+# e.g. 1.0.1-SNAPSHOT -> 1.1.0
+if [ "$OLD_PATCH" -gt 0 ]
+then
+	test "$NEW_MAJOR" -eq "$OLD_MAJOR" \
+		-a "$NEW_MINOR" -eq "$((OLD_MINOR+1))" \
+		-a "$NEW_PATCH" -eq 0 &&
+		succeed "Detected MINOR version bump"
+fi
+
+# check for MAJOR version bump
+# e.g. 1.1.0-SNAPSHOT -> 2.0.0
+# e.g. 1.0.1-SNAPSHOT -> 2.0.0
+if [ "$OLD_PATCH" -gt 0 -o "$OLD_MINOR" -gt 0 ]
+then
+	test "$NEW_MAJOR" -eq "$((OLD_MAJOR+1))" \
+		-a "$NEW_MINOR" -eq 0 \
+		-a "$NEW_PATCH" -eq 0 &&
+		succeed "Detected MAJOR version bump"
+fi
+
+die "Invalid version bump: $SNAPSHOT -> $RELEASE"