build: lock material unit tests job to specific commit (#31569)

No longer locks the Material unit tests job to a specific branch, but rather allows
locking to a specific commit from a given branch. This allows us to use the
"master" branch from the `components` repository.

PR Close #31569

.circleci/config.yml

@@ -141,6 +141,11 @@ var_14: &notify_dev_infra_on_fail
       notificationJson="{\"text\":\":x: \`$CIRCLE_JOB\` job for $CIRCLE_BRANCH branch failed on build $CIRCLE_BUILD_NUM: $CIRCLE_BUILD_URL :scream:\"}"
       curl --request POST --header "Content-Type: application/json" --data "$notificationJson" $SLACK_DEV_INFRA_CI_FAILURES_WEBHOOK_URL
 
+# Cache key for the Material unit tests job. **Note** when updating the SHA in the cache keys,
+# also update the SHA for the "MATERIAL_REPO_COMMIT" environment variable.
+var_15: &material_unit_tests_cache_key v4-angular-material-701302dc482d7e4b77990b24e3b5ab330bbf1aa5
+var_16: &material_unit_tests_cache_key_short v4-angular-material
+
 version: 2
 jobs:
   setup:
@@ -621,27 +626,26 @@ jobs:
       # Although RBE is configured below for the Material repo, also setup RBE in the Angular repo
       # to provision Angular's GCP token into the environment variables.
       - *setup_bazel_remote_execution
-      - run:
-          name: "Cloning Material repository"
-          command: ./scripts/ci/clone_angular_material_repo.sh
+      # Restore the cache before cloning the repository because the clone script re-uses
+      # the restored repository if present. This reduces the amount of times the components
+      # repository needs to be cloned (this is slow and increases based on commits in the repo).
       - restore_cache:
-          # Material directory must be kept in sync with the `$MATERIAL_REPO_TMP_DIR` env variable.
-          # It needs to be hardcoded here, because env variables interpolation is not supported.
           keys:
-            - v2-angular-material-{{ checksum "/tmp/material2/yarn.lock" }}
-            - v2-angular-material-
+            - *material_unit_tests_cache_key
+            - *material_unit_tests_cache_key_short
       - run:
+          name: "Fetching Material repository"
+          command: ./scripts/ci/clone_angular_material_repo.sh
+      - run:
+          # Run yarn install to fetch the Bazel binaries as used in the Material repo.
           name: Installing Material dependencies.
           command: yarn --cwd ${MATERIAL_REPO_TMP_DIR} install --frozen-lockfile --non-interactive
-      # Save the cache before we run the Material unit tests script. This is necessary
-      # because we don't want to cache the node modules which have been modified to contain
-      # the attached Ivy package output.
       - save_cache:
-          # Material directory must be kept in sync with the `$MATERIAL_REPO_TMP_DIR` env variable.
-          # It needs to be hardcoded here, because env variables interpolation is not supported.
-          key: v2-angular-material-{{ checksum "/tmp/material2/yarn.lock" }}
+          key: *material_unit_tests_cache_key
           paths:
-            - "/tmp/material2/node_modules"
+            # Material directory must be kept in sync with the `$MATERIAL_REPO_TMP_DIR` env variable.
+            # It needs to be hardcoded here, because env variables interpolation is not supported.
+            - "/tmp/material2"
       - run:
           name: "Setup Bazel RBE remote execution in Material repo"
           command: |

.circleci/env.sh

@@ -77,7 +77,9 @@ setPublicVar SAUCE_READY_FILE_TIMEOUT 120
 # their separate build setups.
 setPublicVar MATERIAL_REPO_TMP_DIR "/tmp/material2"
 setPublicVar MATERIAL_REPO_URL "https://github.com/angular/material2.git"
-setPublicVar MATERIAL_REPO_TAG "8.1.0"
+setPublicVar MATERIAL_REPO_BRANCH "master"
+# **NOTE**: When updating the commit SHA, also update the cache key in the CircleCI "config.yml".
+setPublicVar MATERIAL_REPO_COMMIT "701302dc482d7e4b77990b24e3b5ab330bbf1aa5"
 
 # Source `$BASH_ENV` to make the variables available immediately.
 source $BASH_ENV;

scripts/ci/clone_angular_material_repo.sh

@@ -2,9 +2,30 @@
 
 set -u -e -o pipefail
 
-# Ensure that the temporary directory does not exist.
-rm -rf ${MATERIAL_REPO_TMP_DIR}
+# Clones the Angular Material repository if the repository has not been cloned before. If
+# the repository is already cloned, the script refreshes the repository by syncing with
+# upstream and resetting to the desired Material commit (see "MATERIAL_REPO_COMMIT" variable).
 
-# Clone the Material repository into the given temporary directory.
-git clone --depth 1 --branch ${MATERIAL_REPO_TAG} ${MATERIAL_REPO_URL} \
-  ${MATERIAL_REPO_TMP_DIR}
+if [[ ! -d "${MATERIAL_REPO_TMP_DIR}" ]]; then
+  # Clone the Material repository if not present through restored cache.
+  git clone --branch ${MATERIAL_REPO_BRANCH} ${MATERIAL_REPO_URL} ${MATERIAL_REPO_TMP_DIR}
+
+  # Switch into the cloned repository.
+  cd ${MATERIAL_REPO_TMP_DIR}
+
+  # Reset branch to the desired commit.
+  git reset --hard ${MATERIAL_REPO_COMMIT}
+else
+  # Switch into the cached repository.
+  cd ${MATERIAL_REPO_TMP_DIR}
+
+  # Only refresh the repository if the current branch HEAD is not
+  # matching the desired commit.
+  if [[ "$(git rev-parse HEAD)" != "${MATERIAL_REPO_COMMIT}" ]]; then
+    # Pull the latest changes of the specified branch.
+    git fetch origin ${MATERIAL_REPO_BRANCH}
+
+    # Reset the current branch to the desired commit.
+    git reset --hard ${MATERIAL_REPO_COMMIT}
+  fi
+fi