MM-69003 Mostly share ESLint config between web app and E2E tests (#36767)

* Switch Cypress to use shared ESLint config

* Run --fix in Cypress

* Manually fix remaining lint issues in Cypress

* Switch Playwright to use shared ESLint config

* Run --fix in Playwright

* Manually fix remaining lint issues in Playwright

* Install and cache web app deps during Cypress CI builds

This also caches the types and client package. That isn't needed currently
since it uses prepackaged versions of those, but I imagine we might change
that at some point.

* Run e2e-tests-check when ESLint plugin is updated

* Change E2E test GHA caching to cache all of web app node_modules

* Fix mismatch between cache save and restore

* Try bumping cache keys

* Copy step to install dependencies to server.run_cypress.sh

I don't know how this must've worked before, but if this fixes the issue,
it seems like neither Cypress nor Playwright actually use the cached
depenendencies.

* Try disabling caching entirely for Cypress tests

* Try bypassing makefile?

* Try also manually building dependencies in run_specs.sh

I don't know why this appears to duplicate run_cypress.sh and
run_playwright.sh, both of which are called run_test.sh which
might not be used any more as best I can tell.

* Try installing the web app dependencies in yet another place

* Disable the extra steps in server.prepare.sh specifically for Cypress

* Revert changes to update cache key and disable web app depenedency cache on Cypress builds

.github/workflows/e2e-tests-check.yml

@@ -5,6 +5,7 @@ on:
     paths:
       - "e2e-tests/**"
       - "webapp/platform/client/**"
+      - "webapp/platform/eslint-plugin/**"
       - "webapp/platform/types/**"
       - ".github/workflows/e2e-*.yml"
 
@@ -38,6 +39,11 @@ jobs:
         # failures in npm's cacache writer.
         run: npm cache verify
 
+      # Set up web app subpackages and eslint plugin
+      - name: ci/get-webapp-node-modules
+        working-directory: webapp
+        run: make node_modules
+
       # Cypress check
       - name: ci/cypress/npm-install
         working-directory: e2e-tests/cypress
@@ -47,9 +53,6 @@ jobs:
         run: npm run check
 
       # Playwright check
-      - name: ci/get-webapp-node-modules
-        working-directory: webapp
-        run: make node_modules
       - name: ci/playwright/npm-install
         working-directory: e2e-tests/playwright
         run: npm ci

.github/workflows/e2e-tests-cypress-template-v2.yml

@@ -216,6 +216,25 @@ jobs:
         uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
         with:
           node-version-file: ".nvmrc"
+      - name: ci/cache-platform-pkgs
+        # `webapp/node_modules/@mattermost/{client,types}` are the workspace
+        # symlinks Node walks up to find when platform/client requires
+        # @mattermost/types. Without them, module resolution fails inside
+        # the slim slice.
+        id: cache-platform-pkgs
+        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        with:
+          path: |
+            webapp/**/node_modules
+            webapp/platform/client/lib
+            webapp/platform/types/lib
+          key: e2e-platform-pkgs-${{ runner.os }}-${{ hashFiles('webapp/package-lock.json', 'webapp/platform/client/src/**', 'webapp/platform/client/tsconfig*.json', 'webapp/platform/types/src/**', 'webapp/platform/types/tsconfig*.json') }}
+      - name: ci/build-platform-pkgs
+        # Full webapp install is needed for tsc + workspace linking; the
+        # postinstall builds platform/{client,types}/lib. We only cache those.
+        if: steps.cache-platform-pkgs.outputs.cache-hit != 'true'
+        working-directory: webapp
+        run: make node_modules
       - name: ci/cache-cypress-deps
         # node_modules + the cypress binary (downloaded to ~/.cache/Cypress by
         # cypress's postinstall, not into node_modules). Both must be cached;
@@ -317,6 +336,17 @@ jobs:
         uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
         with:
           node-version-file: ".nvmrc"
+      - name: ci/restore-platform-pkgs
+        # Built lib/ for @mattermost/client and @mattermost/types, plus the
+        # webapp workspace symlinks under webapp/node_modules/@mattermost/.
+        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        with:
+          path: |
+            webapp/**/node_modules
+            webapp/platform/client/lib
+            webapp/platform/types/lib
+          key: e2e-platform-pkgs-${{ runner.os }}-${{ hashFiles('webapp/package-lock.json', 'webapp/platform/client/src/**', 'webapp/platform/client/tsconfig*.json', 'webapp/platform/types/src/**', 'webapp/platform/types/tsconfig*.json') }}
+          fail-on-cache-miss: true
       - name: ci/restore-cypress-deps
         uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
         with:

.github/workflows/e2e-tests-cypress-template.yml

@@ -222,6 +222,14 @@ jobs:
           node-version-file: ".nvmrc"
           cache: npm
           cache-dependency-path: "e2e-tests/cypress/package-lock.json"
+      - name: ci/npm-cache-verify
+        # Heal any partial/dangling entries left in the restored ~/.npm cache
+        # before running `npm ci`. Avoids the intermittent EEXIST/ENOENT
+        # failures in npm's cacache writer.
+        run: npm cache verify
+      - name: ci/get-webapp-node-modules
+        working-directory: webapp
+        run: make node_modules
       - name: ci/run-tests
         run: |
           make cloud-init

.github/workflows/e2e-tests-playwright-template-v2.yml

@@ -192,12 +192,9 @@ jobs:
         uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
         with:
           path: |
-            webapp/node_modules/@mattermost/client
-            webapp/node_modules/@mattermost/types
+            webapp/**/node_modules
             webapp/platform/client/lib
-            webapp/platform/client/node_modules
             webapp/platform/types/lib
-            webapp/platform/types/node_modules
           key: e2e-platform-pkgs-${{ runner.os }}-${{ hashFiles('webapp/package-lock.json', 'webapp/platform/client/src/**', 'webapp/platform/client/tsconfig*.json', 'webapp/platform/types/src/**', 'webapp/platform/types/tsconfig*.json') }}
       - name: ci/build-platform-pkgs
         # Full webapp install is needed for tsc + workspace linking; the
@@ -319,12 +316,9 @@ jobs:
         uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
         with:
           path: |
-            webapp/node_modules/@mattermost/client
-            webapp/node_modules/@mattermost/types
+            webapp/**/node_modules
             webapp/platform/client/lib
-            webapp/platform/client/node_modules
             webapp/platform/types/lib
-            webapp/platform/types/node_modules
           key: e2e-platform-pkgs-${{ runner.os }}-${{ hashFiles('webapp/package-lock.json', 'webapp/platform/client/src/**', 'webapp/platform/client/tsconfig*.json', 'webapp/platform/types/src/**', 'webapp/platform/types/tsconfig*.json') }}
           fail-on-cache-miss: true
       - name: ci/restore-playwright-deps