Downport "Add a shared pre-commit to run eslintfix for frontend code changes"

This pre-commit hook will fail the commit when you have linter errors.
It will also only run on changed staged files.

Also cleaned up linter config in package and lint_test.

Change-Id: I70d906b5c5c0180d88e0d0ff9840387e9f013fe2

package.json

@@ -15,7 +15,7 @@
   "scripts": {
     "start": "polygerrit-ui/run-server.sh",
     "test": "WCT_HEADLESS_MODE=1 WCT_ARGS='--verbose -l chrome' ./polygerrit-ui/app/run_test.sh",
-    "eslint": "./node_modules/eslint/bin/eslint.js --ignore-pattern 'bower_components/' --ignore-pattern 'gr-linked-text' --ignore-pattern 'scripts/vendor' --ext .html,.js polygerrit-ui/app",
+    "eslint": "./node_modules/eslint/bin/eslint.js --ext .html,.js polygerrit-ui/app",
     "eslintfix": "npm run eslint -- --fix",
     "test-template": "./polygerrit-ui/app/run_template_test.sh",
     "polylint": "bazel test polygerrit-ui/app:polylint_test"

polygerrit-ui/app/lint_test.sh

@@ -30,4 +30,4 @@ cd ${UI_PATH}
 # eslint installation.
 npm link eslint eslint-config-google eslint-plugin-html
 
-${eslint_bin} -c ${UI_PATH}/.eslintrc.json --ignore-pattern 'node_modules/' --ignore-pattern 'bower_components/' --ignore-pattern 'gr-linked-text' --ignore-pattern 'scripts/vendor' --ext .html,.js ${UI_PATH}
+${eslint_bin} -c ${UI_PATH}/.eslintrc.json --ext .html,.js ${UI_PATH}

tools/dev-hooks/pre-commit

@@ -0,0 +1,47 @@
+#!/bin/sh
+#
+# Part of Gerrit Code Review (https://www.gerritcodereview.com/)
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# To enable this hook:
+# - copy this file or content to ".git/hooks/pre-commit"
+# - (optional if you copied this file) make it executable: `chmod +x .git/hooks/pre-commit`
+
+set -ue
+
+# gitroot, default to .
+gitroot=$(git rev-parse --show-cdup)
+gitroot=${gitroot:-.};
+
+# eslint
+eslint=${gitroot}/node_modules/eslint/bin/eslint.js
+
+# Run eslint over changed frontend code
+CHANGED_UI_FILES=$(git diff --cached --name-only -- '*.js' '*.html' | grep 'polygerrit-ui') && true
+if [ "${CHANGED_UI_FILES}" ]; then
+  if $eslint --fix ${CHANGED_UI_FILES}; then
+    # Add again in case lint fix modified some files
+    git add ${CHANGED_UI_FILES}
+    exit 0
+  else
+    echo "Failed to fix all linter issues.";
+    exit 1
+  fi
+else
+  echo "No UI files changed"
+  exit 0
+fi