build(bazel): add version stamping (#10687)

tools/bazel-stamp-vars.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+
+# Generates the data used by the stamping feature in bazel.
+# This script is intended to be used as a Bazel workspace_status_command, which
+# prints out a set of key-value pairs.
+# See https://github.com/angular/angular/blob/master/docs/BAZEL.md for more explanation
+set -u -e -E -o pipefail
+
+function onError {
+  echo "Failed to execute: $0"
+  echo ""
+}
+
+# Setup crash trap
+trap 'onError' ERR
+
+if [[ "$(git tag)" == "" ]]; then
+  echo "No git tags found, can't stamp the build."
+  echo "Either fetch the tags:"
+  echo "       git fetch git@github.com:angular/material2.git --tags"
+  echo "or build without stamping by giving an empty workspace_status_command:"
+  echo "       bazel build --workspace_status_command= ..."
+  echo ""
+fi
+
+# Gets a human-readable name for HEAD, e.g. "6.0.0-rc.0-15-g846ddfa"
+git_version_raw=$(git describe --abbrev=7 --tags HEAD)
+
+# Find out if there are any uncommitted local changes
+if [[ $(git status --untracked-files=no --porcelain) ]]; then
+  local_changes_suffix=".with-local-changes";
+else
+  local_changes_suffix="";
+fi
+
+# Reformat `git describe` version string into a more semver-ish string
+#   From:   5.2.0-rc.0-57-g757f886
+#   To:     5.2.0-rc.0+57.sha-757f886
+#   Or:     5.2.0-rc.0+57.sha-757f886.with-local-changes
+
+semver_style_version="$(echo ${git_version_raw} | sed -E 's/-([0-9]+)-g/+\1.sha-/g')"
+version_stamp="${semver_style_version}${local_changes_suffix}"
+echo "BUILD_SCM_VERSION ${version_stamp}"

tools/bazel.rc

@@ -36,8 +36,9 @@ test --test_output=errors
 build --experimental_ui
 test --experimental_ui
 
-# Output to a more coventional location
-build --symlink_prefix=dist/bazel/
+# Configures script to do version stamping.
+# See https://docs.bazel.build/versions/master/user-manual.html#flag--workspace_status_command
+build --workspace_status_command=./tools/bazel-stamp-vars.sh
 
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