ci: add support for structural tagging

Make structural tagging functions available for both test and build
scripts.

Introduces the update_tag.sh helper for listing, checking, and updating
deterministic tags.

Also adds the ci_tag_build_time_check and ci_tag_test_time_check
functions to validate tags during build and test phases, ensuring
consistent component versioning.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33421>

.gitlab-ci/container/container_pre_build.sh

@@ -1,4 +1,7 @@
 #!/bin/sh
+# When changing this file, you need to bump the following
+# .gitlab-ci/image-tags.yml tags:
+# DEBIAN_BUILD_TAG
 
 if test -x /usr/bin/ccache; then
     if test -f /etc/debian_version; then
@@ -49,3 +52,23 @@ if [ -f "$CARGO_ENV_FILE" ]; then
     # shellcheck disable=SC1090
     source "$CARGO_ENV_FILE"
 fi
+
+ci_tag_early_checks() {
+    # Runs the first part of the build script to perform the tag check only
+    uncollapsed_section_switch "ci_tag_early_checks" "Ensuring component versions match declared tags in CI builds"
+    echo "[Structured Tagging] Checking components: ${CI_BUILD_COMPONENTS}"
+    # shellcheck disable=SC2086
+    for component in ${CI_BUILD_COMPONENTS}; do
+        bin/ci/update_tag.py --check ${component} || exit 1
+    done
+    echo "[Structured Tagging] Components check done"
+    section_end "ci_tag_early_checks"
+}
+
+# Check if each declared tag component is up to date before building
+if [ -n "${CI_BUILD_COMPONENTS:-}" ]; then
+    # Remove any duplicates by splitting on whitespace, sorting, then joining back
+    CI_BUILD_COMPONENTS="$(echo "${CI_BUILD_COMPONENTS}" | xargs -n1 | sort -u | xargs)"
+
+    ci_tag_early_checks
+fi