ci: reset cache when patches change (angular#48521)

This will help making it easier to update patches when `node_modules`
are cached. Note that most of the time this shouldn't be necessary
as we only cache the Yarn `.cache` for the non-windows jobs. Windows
job caches `node_modules` directly- so could be affected and needs
a cache reset/wipe occasionally when patches change (even though it's
rarely). Long-term we can remove this when the esm patches are no longer
needed.

PR Close angular#48521

Author: devversion

.circleci/config.yml

@@ -23,16 +23,18 @@ version: 2.1
 #              (See https://support.circleci.com/hc/en-us/articles/360012618473-Creating-a-daily-cache.)
 # **NOTE 2 **: If you change the cache key prefix, also sync the cache_key_fallback to match.
 # **NOTE 3 **: Keep the static part of the cache key as prefix to enable correct fallbacks.
+# **NOTE 4 **: To make sure modified patches can be applied without needing to manually update the cache key,
+#              the fallback cache key will not match if patches have been modified.
 # See https://circleci.com/docs/2.0/caching/#restoring-cache for how prefixes work in CircleCI.
-var_3: &cache_key v8-angular-node-16-{{ checksum "month.txt" }}-{{ checksum ".bazelversion" }}-{{ checksum "yarn.lock" }}-{{ checksum "WORKSPACE" }}-{{ checksum "aio/yarn.lock" }}
+var_3: &cache_key v8-angular-node-16-{{ checksum "month.txt" }}-{{ checksum "patches.hash"}}-{{ checksum ".bazelversion" }}-{{ checksum "yarn.lock" }}-{{ checksum "WORKSPACE" }}-{{ checksum "aio/yarn.lock" }}
 # We invalidate the cache if the Bazel version changes because otherwise the `bazelisk` cache
 # folder will contain all previously used versions and ultimately cause the cache restoring to
 # be slower due to its growing size.
-var_4: &cache_key_fallback v8-angular-node-16-{{ checksum "month.txt" }}-{{ checksum ".bazelversion" }}
+var_4: &cache_key_fallback v8-angular-node-16-{{ checksum "month.txt" }}-{{ checksum "patches.hash"}}-{{ checksum ".bazelversion" }}
 
 # Windows needs its own cache key because binaries in node_modules are different.
-var_3_win: &cache_key_win v10-angular-win-node-16-{{ checksum "month.txt" }}-{{ checksum ".bazelversion" }}-{{ checksum "yarn.lock" }}-{{ checksum "WORKSPACE" }}
-var_4_win: &cache_key_win_fallback v10-angular-win-node-16-{{ checksum "month.txt" }}-{{ checksum ".bazelversion" }}
+var_3_win: &cache_key_win v10-angular-win-node-16-{{ checksum "month.txt" }}-{{ checksum "patches.hash"}}-{{ checksum ".bazelversion" }}-{{ checksum "yarn.lock" }}-{{ checksum "WORKSPACE" }}
+var_4_win: &cache_key_win_fallback v10-angular-win-node-16-{{ checksum "month.txt" }}-{{ checksum "patches.hash"}}-{{ checksum ".bazelversion" }}
 
 # Workspace initially persisted by the `setup` job, and then enhanced by `build-npm-packages`.
 # https://circleci.com/docs/2.0/workflows/#using-workspaces-to-share-data-among-jobs
@@ -182,6 +184,12 @@ commands:
           # snapshot stamping would have the `-with-local-changes` suffix.
           command: date +%Y-%m > month.txt
 
+  capture_patches_for_cache_key:
+    description: Hashes all patches so that the cache can be reset upon changes.
+    steps:
+      - run: |
+          md5sum tools/esm-interop/patches/npm/* > patches.hash
+
   yarn_install:
     description: Install dependencies
     steps:
@@ -214,6 +222,7 @@ jobs:
     steps:
       - checkout
       - save_month_to_file
+      - capture_patches_for_cache_key
       - init_environment
       - devinfra/rebase-pr-on-target-branch:
           base_revision: << pipeline.git.base_revision >>
@@ -590,6 +599,7 @@ jobs:
     steps:
       - checkout
       - save_month_to_file
+      - capture_patches_for_cache_key
       - init_environment
 
       # Setup the proper NodeJS version. The image comes pre-installed with `nvm-windows`.