Clang-format git hook pre-commit enforcement (#760)

* Added clang-format git pre-commit hook

Signed-off-by: The MathWorks, Inc. <alchrist@mathworks.com>

* Updated README

* Updated help instructions to include '--style=file'

* Added '--style=file' flag in actual pre-commit hook check

* Updated README

* Removed unnecessary code in pre-commit hook

* Updated README

Signed-off-by: The MathWorks, Inc. <alchrist@mathworks.com>

.githooks/pre-commit

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# Run clang-format pre-commit hook
+sh .githooks/pre-commit-clang-format-hook

.githooks/pre-commit-clang-format-hook

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+printf "Running clang-format pre-commit hook... ";
+
+CLANG_FORMAT=$(which clang-format)
+
+if [ ! -x "$CLANG_FORMAT" ]; then
+  printf "Error.\n";
+  printf "The clang-format cannot be found in your PATH. Please ensure clang-format is installed and on the PATH."
+  exit 1
+fi
+
+# Get clang-format output and store it for later checking
+clangformatoutput=$(git clang-format --style=file --diff --staged -q)
+
+# Redirect output to stderr
+exec 1>&2
+
+if [ "$clangformatoutput" != "" ];
+then
+  printf "Error.\n";
+  printf "clang-format detected that changes have been made and are not properly formatted!\n"
+  printf "Please run \`git clang-format --style=file --staged\`, re-stage modified files, and commit.\n"
+  exit 1
+else
+  printf "Success.\n";
+fi

CMakeLists.txt

@@ -27,6 +27,19 @@ foreach(policy ${policies_new})
   endif()
 endforeach()
 
+#-----------------------------------------------------------------------------
+# Setup git hooks
+#-----------------------------------------------------------------------------
+find_package(Git)
+if (GIT_FOUND AND EXISTS "${PROJECT_SOURCE_DIR}/.git")
+  execute_process(COMMAND ${GIT_EXECUTABLE} config core.hooksPath "${PROJECT_SOURCE_DIR}/.githooks"
+                          WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+                          RESULT_VARIABLE GIT_CONFIGMOD_RESULT)
+  if (NOT GIT_CONFIGMOD_RESULT EQUAL "0")
+    message(WARNING "Command `git config core.hooksPath ${PROJECT_SOURCE_DIR}/.githooks` failed with ${GIT_CONFIGMOD_RESULT}")
+  endif()
+endif()
+
 #-----------------------------------------------------------------------------
 # Check minimum required compiler versions
 #------------------------------------------------------------------------------

README.rst

@@ -223,3 +223,22 @@ file for details about the contribution process.
    :target: https://codecov.io/gh/cppmicroservices/CppMicroServices/branch/master
 .. |Code Coverage Status (development)| image:: https://img.shields.io/codecov/c/github/CppMicroServices/CppMicroServices/development.svg?style=flat-square
    :target: https://codecov.io/gh/cppmicroservices/CppMicroServices/branch/development
+
+Git Hooks General Information
+-----------------------------
+
+The CppMicroServices repository defines its git hooks in the `.githooks` directory. This directory is
+set as the directory for git hooks via executing `git config core.hooksPath <path>` in our `CMakeLists.txt` file.
+
+Git Hooks Failure Help
+----------------------
+
+If the clang-format pre-commit hook fails because `clang-format` is not installed, please install it and
+put it on the path. Similarly, if `git-clang-format` is not installed, do the same. `git-clang-format` comes
+with the LLVM distribution of `clang-format`.
+
+If this is not feasible for you, you can specify `--no-verify` when committing your changes. This is heavily discouraged
+and you must provide a justification as to why you are unable to format your commit.
+
+We reserve the right to reject any pull requests that are not properly formatted and do not have a
+valid justification specified.

third_party/.clang-format

@@ -0,0 +1,4 @@
+{
+    "DisableFormat": true,
+    "SortIncludes": false,
+}