Make a few improvements to linting (#8184)

Use our own script for the yamllint check. This allows us to only
look at modified files and run it locally as part of lint.sh

Made some misc cleanups to the other bash scripts along the way, like
making check_tabs.sh not hang forever if there are no modified files
(grep gets passed an empty list of files and then sits there waiting
for input).

.github/workflows/lint.yml

@@ -123,9 +123,10 @@ jobs:
   yamllint:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
-      - name: yaml-lint
-        uses: ibiqlik/action-yamllint@v1
-        with:
-          strict: true
-          file_or_dir: .github/**/*.yml build_tools/buildkite/**/*.yml
+      - name: Checking out repository
+        uses: actions/checkout@v2
+      - name: Fetching Base Branch
+        # We have to explicitly fetch the base branch as well
+        run: git fetch --no-tags --prune --depth=1 origin "${GITHUB_BASE_REF?}:${GITHUB_BASE_REF?}"
+      - name: yamllint
+        run: ./scripts/run_yamllint.sh

scripts/check_tabs.sh

@@ -18,6 +18,7 @@ declare -a excluded_files_patterns=(
   "/third_party/"
   "^third_party/"
   "*Makefile*"
+  # Symlinks make grep upset
   "^integrations/tensorflow/iree-dialects$"
 )
 
@@ -28,6 +29,10 @@ readarray -t files < <(\
   (git diff --name-only --diff-filter=d "${BASE_REF}" || kill $$) \
     | grep -v -E "${excluded_files_pattern?}")
 
+if (( ${#files[@]} == 0 )); then
+  exit 0
+fi;
+
 diff="$(grep --with-filename --line-number --perl-regexp --binary-files=without-match '\t' "${files[@]}")"
 
 grep_exit="$?"

scripts/lint.sh

@@ -74,7 +74,7 @@ fi
 echo "***** yapf *****"
 # Don't fail script if condition is false
 disable_update_ret
-if exists yapf > /dev/null; then
+if exists yapf; then
   enable_update_ret
   git diff -U0 main | ./third_party/format_diff/format_diff.py yapf -i
 else
@@ -109,9 +109,16 @@ echo "***** tabs *****"
 ./scripts/check_tabs.sh
 
 echo "***** yamllint *****"
-echo "'yamllint' check not yet implemented. Skipping check"
+disable_update_ret
+if exists yamllint; then
+  enable_update_ret
+  ./scripts/run_yamllint.sh
+else
+  enable_update_ret
+  echo "'yamllint' not found. Skipping check"
+fi
 
-if [[ "${FINAL_RET}" -ne 0 ]]; then
+if (( "${FINAL_RET}" != 0 )); then
   echo "Encountered failures. Check error messages and changes to the working" \
        "directory and git index (which may contain fixes) and try again."
 fi

scripts/run_buildifier.sh

@@ -35,7 +35,7 @@ readarray -t files < <(\
     | grep -E "${included_files_pattern?}" \
     | grep -v -E "${excluded_files_pattern?}")
 
-if [ ${#files[@]} -eq 0 ]; then
+if (( ${#files[@]} == 0 )); then
   echo "No Bazel files changed"
   exit 0
 fi

scripts/run_yamllint.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+# Copyright 2021 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+# Runs yamllint on files modified vs the specified reference commit
+# (default "main")
+
+set -uo pipefail
+
+BASE_REF="${1:-main}"
+
+declare -a included_files_patterns=(
+  "\.yaml$"
+  "\.yml$"
+)
+
+declare -a excluded_files_patterns=(
+  "/third_party/"
+  "^third_party/"
+)
+
+# Join on |
+included_files_pattern="$(IFS="|" ; echo "${included_files_patterns[*]?}")"
+excluded_files_pattern="$(IFS="|" ; echo "${excluded_files_patterns[*]?}")"
+
+readarray -t files < <(\
+  (git diff --name-only --diff-filter=d "${BASE_REF}" || kill $$) \
+    | grep -E "${included_files_pattern?}" \
+    | grep -v -E "${excluded_files_pattern?}")
+
+if (( ${#files[@]} == 0 )); then
+  echo "No Yaml files changed"
+  exit 0
+fi
+
+
+yamllint --strict "${files[@]}"