Add cpplint to CI

CPPLINT.cfg

@@ -0,0 +1,14 @@
+set noparent
+linelength=120  # As in .clang-format
+
+# Non-used filters
+filter=-build/include_order  # Requires unusual include order that encourages creating not self-contained headers
+filter=-readability/nolint  # Conficts with clang-tidy
+filter=-runtime/references  # Requires fundamental change of API, don't see need for this
+filter=-whitespace/blank_line  # Unnecessarily strict with blank lines that otherwise help with readability
+filter=-whitespace/parens,-whitespace/braces  # Conflict with clang-format
+
+# Filters to be included in future
+filter=-whitespace/indent,-whitespace/comments,-readability/braces,-build/include_what_you_use
+filter=-legal/copyright  # Remove this line after Version 1.9
+

azure-pipelines.yml

@@ -31,6 +31,14 @@ jobs:
     - script: git diff --exit-code --color
       displayName: Check tidy
 
+- job: CppLint
+  pool:
+    vmImage: 'ubuntu-latest'
+  container: sharaku/cpplint:latest
+  steps:
+    - bash: cpplint --counting=detailed --recursive examples include/CLI
+      displayName: Checking against google style guide
+
 # TODO: Fix macOS error and windows warning in c++17 mode
 - job: Native
   strategy:
@@ -97,4 +105,3 @@ jobs:
     - template: .ci/azure-cmake.yml
     - template: .ci/azure-build.yml
     - template: .ci/azure-test.yml
-

examples/subcom_in_files/subcommand_a.hpp

@@ -1,3 +1,4 @@
+#pragma once
 // ===================================================================
 //   subcommand_a.hpp
 // ===================================================================

include/CLI/App.hpp

@@ -2657,9 +2657,7 @@ class App {
             auto res = op->get_flag_value(arg_name, value);
             op->add_result(res);
             parse_order_.push_back(op.get());
-        }
-        // --this=value
-        else if(!value.empty()) {
+        } else if(!value.empty()) { // --this=value
             op->add_result(value, result_count);
             parse_order_.push_back(op.get());
             collected += result_count;

include/CLI/Timer.hpp

@@ -10,7 +10,7 @@
 #endif
 
 #include <array>
-#include <chrono>
+#include <chrono> // NOLINT(build/c++11)
 #include <functional>
 #include <iostream>
 #include <string>
@@ -87,8 +87,9 @@ class Timer {
     /// This prints out a time string from a time
     std::string make_time_str(double time) const {
         auto print_it = [](double x, std::string unit) {
-            std::array<char, 50> buffer;
-            std::snprintf(buffer.data(), 50, "%.5g", x);
+            const unsigned int buffer_length = 50;
+            std::array<char, buffer_length> buffer;
+            std::snprintf(buffer.data(), buffer_length, "%.5g", x);
             return buffer.data() + std::string(" ") + unit;
         };
 

include/CLI/TypeTools.hpp

@@ -4,6 +4,7 @@
 // file LICENSE or https://github.com/CLIUtils/CLI11 for details.
 
 #include "StringTools.hpp"
+#include <cstdint>
 #include <exception>
 #include <memory>
 #include <string>
@@ -595,9 +596,9 @@ template <typename T,
 bool lexical_cast(const std::string &input, T &output) {
     try {
         std::size_t n = 0;
-        long long output_ll = std::stoll(input, &n, 0);
+        std::int64_t output_ll = std::stoll(input, &n, 0);
         output = static_cast<T>(output_ll);
-        return n == input.size() && static_cast<long long>(output) == output_ll;
+        return n == input.size() && static_cast<std::int64_t>(output) == output_ll;
     } catch(const std::invalid_argument &) {
         return false;
     } catch(const std::out_of_range &) {
@@ -614,9 +615,9 @@ bool lexical_cast(const std::string &input, T &output) {
 
     try {
         std::size_t n = 0;
-        unsigned long long output_ll = std::stoull(input, &n, 0);
+        std::uint64_t output_ll = std::stoull(input, &n, 0);
         output = static_cast<T>(output_ll);
-        return n == input.size() && static_cast<unsigned long long>(output) == output_ll;
+        return n == input.size() && static_cast<std::uint64_t>(output) == output_ll;
     } catch(const std::invalid_argument &) {
         return false;
     } catch(const std::out_of_range &) {

include/CLI/Validators.hpp

@@ -35,7 +35,7 @@
 #endif
 
 #if defined CLI11_HAS_FILESYSTEM && CLI11_HAS_FILESYSTEM > 0
-#include <filesystem>
+#include <filesystem> // NOLINT(build/include)
 #else
 #include <sys/stat.h>
 #include <sys/types.h>