cmake format target: add whitespace correction (apache#12696)

Our format target does formatting of C++ and Python files via
clang-format and yapf. Annoyingly, it hasn't done some extra whitespace
checks that CI does. So a PR can be made that passes `format` locally
but then CI will reject it for trailing whitespace, or DOS line endinds.
This adds a new tools/whitespace-format.sh script that automatically
fixes trailing whitespace and DOS carriage returns, matching the checks
performed by CI. This script is then integrated into the `format` cmake
target so it gets run for that.

I verified that the script works on both Linux and Mac.

Author: bneradt

CMakeLists.txt

@@ -806,10 +806,18 @@ add_custom_target(
   VERBATIM
 )
 
+add_custom_target(
+  whitespace-format
+  ${CMAKE_SOURCE_DIR}/tools/whitespace-format.sh
+  WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+  COMMENT "fixing whitespace issues (trailing whitespace, DOS line endings)"
+  VERBATIM
+)
+
 # Add a format target that runs all the formatters.
 add_custom_target(
   format
-  DEPENDS clang-format yapf cmake-format
+  DEPENDS clang-format yapf cmake-format whitespace-format
   COMMENT "formatting all files"
 )
 

tools/git/pre-commit

@@ -123,6 +123,32 @@ else
     echo
 fi
 
+# Check for trailing whitespace in staged files.
+TRAILING_WS=$(git diff-index --cached --diff-filter=ACMR --name-only HEAD | grep -vE "lib/(yamlcpp|Catch2|systemtap)" | grep -vE "\.(gold|test_input)$" | xargs git diff --cached | grep -E '^\+.*[[:space:]]$' || true)
+if [ -n "$TRAILING_WS" ]; then
+    echo "The commit is not accepted because it contains trailing whitespace."
+    echo "The easiest way to fix this is to run:"
+    echo
+    echo "    $ cmake --build <build_dir> --target format"
+    exit 1
+else
+    echo "This commit complies with the trailing whitespace rules."
+    echo
+fi
+
+# Check for DOS carriage returns in staged files.
+DOS_CR=$(git diff-index --cached --diff-filter=ACMR --name-only HEAD | grep -vE "lib/(yamlcpp|Catch2|systemtap)" | grep -vE "\.test_input$" | xargs git diff --cached | grep -E '^\+.*\r$' || true)
+if [ -n "$DOS_CR" ]; then
+    echo "The commit is not accepted because it contains DOS carriage returns."
+    echo "The easiest way to fix this is to run:"
+    echo
+    echo "    $ cmake --build <build_dir> --target format"
+    exit 1
+else
+    echo "This commit complies with the DOS line ending rules."
+    echo
+fi
+
 # Cleanup before exit
 rm -f "$clang_patch_file" "$yapf_patch_file"
 exit 0

tools/whitespace-format.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+#
+#  Script to fix whitespace issues: trailing whitespace and DOS carriage returns.
+#
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you 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.
+
+set -e
+
+REPO_ROOT=$(cd $(dirname $0) && git rev-parse --show-toplevel)
+echo "Fixing whitespace issues in ${REPO_ROOT}"
+
+# macOS requires an empty string argument for in-place sed edits.
+if [[ "$OSTYPE" == "darwin"* ]]; then
+    SED_INPLACE=(sed -i '')
+else
+    SED_INPLACE=(sed -i)
+fi
+
+FILES_MODIFIED=0
+
+echo "Checking for trailing whitespace..."
+TRAILING_WS_FILES=$(git grep -IE ' +$' | eval "grep -F -v 'lib/yamlcpp' | grep -F -v 'lib/Catch2' | grep -F -v 'lib/systemtap' | grep -F -v '.gold:' | grep -F -v '.test_input'" | cut -d: -f1 | sort -u || true)
+
+if [ -n "$TRAILING_WS_FILES" ]; then
+    while IFS= read -r file; do
+        if [ -f "$file" ]; then
+            echo "  Fixing trailing whitespace in: $file"
+            "${SED_INPLACE[@]}" 's/[[:space:]]*$//' "$file"
+            FILES_MODIFIED=$((FILES_MODIFIED + 1))
+        fi
+    done <<< "$TRAILING_WS_FILES"
+fi
+
+echo "Checking for DOS carriage returns..."
+DOS_FILES=$(git grep -IE $'\r$' | eval "grep -F -v 'lib/yamlcpp' | grep -F -v 'lib/Catch2' | grep -F -v 'lib/systemtap' | grep -F -v '.test_input'" | cut -d: -f1 | sort -u || true)
+
+if [ -n "$DOS_FILES" ]; then
+    while IFS= read -r file; do
+        if [ -f "$file" ]; then
+            echo "  Removing DOS carriage returns from: $file"
+            "${SED_INPLACE[@]}" $'s/\r$//' "$file"
+            FILES_MODIFIED=$((FILES_MODIFIED + 1))
+        fi
+    done <<< "$DOS_FILES"
+fi
+
+if [ $FILES_MODIFIED -eq 0 ]; then
+    echo "Success! No whitespace issues found."
+else
+    echo "Fixed whitespace issues in $FILES_MODIFIED file(s)."
+fi
+
+exit 0
+