CICD: Add Script to Find the Changeset ID for a CICD Release Number.

Add a script that finds the changeset ID in the subsurface repository
that a given CICD release was built from.
The option '-c' can be used to check out the changeset, if one is found.

Signed-off-by: Michael Keller <mikeller@042.ch>

scripts/get-changeset-id.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+#
+# find the changeset id for a given CICD release number
+# and optionally checkout the resulting changeset
+#
+#
+# we ignore the base version here - all that is expected is the 'patch' part of the version
+
+# little silly helper functions
+croak() {
+	echo "$0: $*" >&2
+	exit 1
+}
+croak_usage() {
+	croak "Usage: $0 <patch_version_number> [-c]"
+}
+
+if [[ $# -gt 2 ]] ; then croak_usage ; fi
+CICD_VERSION=$1
+if [[ $# -eq 2 ]] ; then
+	if [[ $2 != "-c" ]] ; then croak_usage ; fi
+	DO_CHECKOUT=1
+fi
+
+# figure out where we are in the file system
+pushd . &> /dev/null
+cd "$(dirname "$0")/../"
+pushd . &> /dev/null
+
+if [ ! -d "./nightly-builds" ] ; then
+	git clone https://github.com/subsurface/nightly-builds &> /dev/null || croak "failed to clone nightly-builds repo"
+fi
+cd nightly-builds
+git fetch &> /dev/null
+
+BUILD_SHA=""
+BUILD_BRANCHES=$(git branch -a --sort=-committerdate --list origin/branch-for-\* | cut -d/ -f3)
+for BUILD_BRANCH in $BUILD_BRANCHES ; do
+	git checkout $BUILD_BRANCH &> /dev/null
+	if [[ $(<./latest-subsurface-buildnumber) == $CICD_VERSION ]]; then
+		BUILD_SHA=$(cut -d- -f 3 <<< "$BUILD_BRANCH")
+		break
+	fi
+done
+
+popd &> /dev/null
+
+printf '%s' "$BUILD_SHA"
+
+if [[ "$DO_CHECKOUT" == "1" && $BUILD_SHA != "" ]]; then
+	git checkout $BUILD_SHA &> /dev/null
+fi
+
+popd &> /dev/null