Make stamping reproducible in CI

Signed-off-by: Amaury Pouly <[email protected]>

ci/bazelisk.sh

@@ -31,6 +31,11 @@ fi
 # See #14695 for more information.
 echo "build --remote_default_exec_properties=OSVersion=\"$(lsb_release -ds)\"" >> "${GCP_BAZELRC}"
 
+# Override workspace status in CI.
+# NOTE: it seems the first instance of --workspace_status_command has precedence so this
+# will override the one in .bazelrc, but this behaviour does not seem to be documented.
+echo "build --workspace_status_command=ci/scripts/get_workspace_status.sh" >> "${GCP_BAZELRC}"
+
 "$(dirname $0)"/../bazelisk.sh \
   --bazelrc="${GCP_BAZELRC}" \
   --bazelrc="$(dirname $0)"/.bazelrc \

ci/scripts/get_workspace_status.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+# This script is passed to bazel's `--workspace_status_command` to generate
+# the workspace status. To ensure reproducible builds, we output constant
+# values.
+
+echo "BUILD_GIT_VERSION OpenTitanCI"
+echo "BUILD_SCM_REVISION 123456789"
+echo "BUILD_SCM_STATUS modified"
+echo "BUILD_TIMESTAMP 315532800"