CI: add abi-consistency-checking

ci/abicheck.sh

@@ -0,0 +1,73 @@
+#! /bin/sh
+#
+# SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Compares the ABI of the current working tree with the ABI
+# from a base-version. Uses libabigail for the actual comparison.
+#
+# To use the tool, just run the script. It will build Calamares at
+# least once, maybe twice (if it needs the base-version ABI information
+# and hasn't cached it).
+
+# The base version can be a tag or git-hash; it will be checked-out
+# in a worktree.
+#
+# Note that the hash here now is the very start of 3.3, when ABI
+# compatibility was not expected yet at **all**.
+BASE_VERSION=419be4df25bc6fcc1958cb6e44afc1b9e64fce71
+
+### Build a tree and cache the ABI info into ci/
+#
+#
+do_build() {
+	LABEL=$1
+	SOURCE_DIR=$2
+
+	BUILD_DIR=build-abi-$LABEL
+	rm -rf $BUILD_DIR
+	mkdir $BUILD_DIR
+
+	if ( cd $BUILD_DIR && cmake $SOURCE_DIR -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS="-Og -g -gdwarf" -DCMAKE_C_FLAGS="-Og -g -gdwarf" && make -j12 ) > /dev/null 2>&1
+	then
+		ls -1 $BUILD_DIR/libcalamares*.so.*
+		# Copy the un-versioned files; .so is a symlink to the just-built one
+		for lib in $BUILD_DIR/libcalamares*.so
+		do
+			cp $lib ci/`basename $lib`.$LABEL
+		done
+	else
+		echo "! failed to build $LABEL"
+		exit 1
+	fi
+}
+
+### Build current tree and get ABI info
+#
+#
+do_build current `pwd -P`
+
+### Build ABI base version
+#
+# We cache this to save on some build time, if we are chasing a
+# single branch from an unchanging base version.
+#
+if test -f ci/libcalamares.so.$BASE_VERSION
+then
+	# The ABI version is cached, so we're good
+	:
+else
+	git worktree remove --force tree-abi-$BASE_VERSION
+	git worktree add tree-abi-$BASE_VERSION $BASE_VERSION > /dev/null 2>&1 || { echo "! could not create worktree for $BASE_VERSION" ; exit 1 ; }
+	do_build $BASE_VERSION $( cd tree-abi-$BASE_VERSION && pwd -P )
+fi
+
+### Compare & Report
+#
+# abidiff compares the Application Binary Interfaces (ABI) of two
+# shared libraries in ELF format. It emits a meaningful report describing
+# the differences between the two ABIs.
+#
+# -l prints only the leaf changes, leaving out explanations of why.
+#
+abidiff -l ci/libcalamares.so.$BASE_VERSION ci/libcalamares.so.current