From 6b5651e6b1723f7d59466afe2e533df3c31eb2d4 Mon Sep 17 00:00:00 2001
From: Wes McKinney <wes.mckinney@twosigma.com>
Date: Wed, 25 Oct 2017 16:01:34 -0400
Subject: [PATCH] Implement check-format in run_clang_format.py, run in Travis
 CI

Change-Id: I889493b66361f6ee08a5b7be2e849fc3d156d25b
---
 .travis.yml                           |  2 ++
 ci/travis_lint.sh                     |  4 +++
 ci/travis_script_cpp.sh               |  8 ------
 cpp/CMakeLists.txt                    |  8 +++---
 cpp/build-support/run_clang_format.py | 40 +++++++++++++++++----------
 cpp/src/arrow/array.h                 |  3 +-
 6 files changed, 38 insertions(+), 27 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index c682a9d9db89f..039ae95208b74 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -56,6 +56,8 @@ matrix:
     - export ARROW_TRAVIS_USE_TOOLCHAIN=1
     - export ARROW_TRAVIS_VALGRIND=1
     - export ARROW_TRAVIS_PLASMA=1
+    - export ARROW_TRAVIS_CLANG_FORMAT=1
+    - $TRAVIS_BUILD_DIR/ci/travis_install_clang_tools.sh
     - $TRAVIS_BUILD_DIR/ci/travis_lint.sh
     - $TRAVIS_BUILD_DIR/ci/travis_before_script_cpp.sh
     script:
diff --git a/ci/travis_lint.sh b/ci/travis_lint.sh
index 8c956646cb39e..e234b7b015b8d 100755
--- a/ci/travis_lint.sh
+++ b/ci/travis_lint.sh
@@ -26,6 +26,10 @@ pushd $TRAVIS_BUILD_DIR/cpp/lint
 cmake ..
 make lint
 
+if [ "$ARROW_TRAVIS_CLANG_FORMAT" == "1" ]; then
+  make check-format
+fi
+
 popd
 
 # Fail fast on style checks
diff --git a/ci/travis_script_cpp.sh b/ci/travis_script_cpp.sh
index a2079036c4549..3d61bc5b89b71 100755
--- a/ci/travis_script_cpp.sh
+++ b/ci/travis_script_cpp.sh
@@ -27,14 +27,6 @@ git archive HEAD --prefix=apache-arrow/ --output=arrow-src.tar.gz
 
 pushd $CPP_BUILD_DIR
 
-# ARROW-209: checks depending on the LLVM toolchain are disabled temporarily
-# until we are able to install the full LLVM toolchain in Travis CI again
-
-# if [ $TRAVIS_OS_NAME == "linux" ]; then
-#   make check-format
-#   make check-clang-tidy
-# fi
-
 ctest -VV -L unittest
 
 popd
diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index a159b1e5674b4..d8dc5df88b4a4 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -446,10 +446,10 @@ add_custom_target(format ${BUILD_SUPPORT_DIR}/run_clang_format.py
 # runs clang format and exits with a non-zero exit code if any files need to be reformatted
 
 # TODO(wesm): Make this work in run_clang_format.py
-# add_custom_target(check-format ${BUILD_SUPPORT_DIR}/run_clang_format.py
-#   ${CLANG_FORMAT_VERSION}
-#   ${BUILD_SUPPORT_DIR}/clang_format_exclusions.txt
-#   ${CMAKE_CURRENT_SOURCE_DIR}/src 1)
+add_custom_target(check-format ${BUILD_SUPPORT_DIR}/run_clang_format.py
+   ${CLANG_FORMAT_VERSION}
+   ${BUILD_SUPPORT_DIR}/clang_format_exclusions.txt
+   ${CMAKE_CURRENT_SOURCE_DIR}/src 1)
 
 ############################################################
 # "make clang-tidy" and "make check-clang-tidy" targets
diff --git a/cpp/build-support/run_clang_format.py b/cpp/build-support/run_clang_format.py
index f1a448f536101..fcf39ecc6a5f9 100755
--- a/cpp/build-support/run_clang_format.py
+++ b/cpp/build-support/run_clang_format.py
@@ -31,6 +31,12 @@
 EXCLUDE_GLOBS_FILENAME = sys.argv[2]
 SOURCE_DIR = sys.argv[3]
 
+if len(sys.argv) > 4:
+    CHECK_FORMAT = int(sys.argv[4]) == 1
+else:
+    CHECK_FORMAT = False
+
+
 exclude_globs = [line.strip() for line in open(EXCLUDE_GLOBS_FILENAME, "r")]
 
 files_to_format = []
@@ -49,18 +55,24 @@
         if not excluded:
             files_to_format.append(name)
 
-# TODO(wesm): Port this to work with Python, for check-format
-# NUM_CORRECTIONS=`$CLANG_FORMAT -output-replacements-xml  $@ |
-# grep offset | wc -l`
-# if [ "$NUM_CORRECTIONS" -gt "0" ]; then
-#   echo "clang-format suggested changes, please run 'make format'!!!!"
-#   exit 1
-# fi
+if CHECK_FORMAT:
+    output = subprocess.check_output([CLANG_FORMAT, '-output-replacements-xml']
+                                     + files_to_format,
+                                     stderr=subprocess.STDOUT).decode('utf8')
+
+    to_fix = []
+    for line in output.split('\n'):
+        if 'offset' in line:
+            to_fix.append(line)
 
-try:
-    cmd = [CLANG_FORMAT, '-i'] + files_to_format
-    subprocess.check_output(cmd, stderr=subprocess.STDOUT)
-except Exception as e:
-    print(e)
-    print(' '.join(cmd))
-    raise
+    if len(to_fix) > 0:
+        print("clang-format checks failed, run 'make format' to fix")
+        sys.exit(-1)
+else:
+    try:
+        cmd = [CLANG_FORMAT, '-i'] + files_to_format
+        subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+    except Exception as e:
+        print(e)
+        print(' '.join(cmd))
+        raise
diff --git a/cpp/src/arrow/array.h b/cpp/src/arrow/array.h
index afbd780dd3ad5..83cda33d1a6d0 100644
--- a/cpp/src/arrow/array.h
+++ b/cpp/src/arrow/array.h
@@ -86,7 +86,8 @@ struct Decimal;
 struct ARROW_EXPORT ArrayData {
   ArrayData() : length(0) {}
 
-  ArrayData(const std::shared_ptr<DataType>& type, int64_t length,
+  ArrayData(
+      const std::shared_ptr<DataType>& type, int64_t length,
             int64_t null_count = kUnknownNullCount, int64_t offset = 0)
       : type(type), length(length), null_count(null_count), offset(offset) {}