Enable -Werror on CI

Increase warning level on MSVC when compiling with FMT_PEDANTIC

CMakeLists.txt

@@ -80,6 +80,8 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wshift-overflow=2
           -Wnull-dereference -Wduplicated-cond)
   endif ()
+
+  set(WERROR_FLAG -Werror)
 endif ()
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
@@ -87,6 +89,13 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
       -Wno-weak-vtables -Wno-padded -Wno-gnu-statement-expression
       -Wno-c++98-compat -Wno-c++98-compat-pedantic -Wno-reserved-id-macro
       -Wno-global-constructors -Wno-disabled-macro-expansion)
+
+  set(WERROR_FLAG -Werror)
+endif ()
+
+if (MSVC)
+  set(PEDANTIC_COMPILE_FLAGS /W4)
+  set(WERROR_FLAG /WX)
 endif ()
 
 if (MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
@@ -135,6 +144,9 @@ add_library(fmt::fmt ALIAS fmt)
 # Starting with CMake 3.1 the CXX_STANDARD property can be used instead.
 # Don't export -std since it may break projects that use other standards.
 target_compile_options(fmt PRIVATE ${CPP14_FLAG})
+if (FMT_WERROR)
+  target_compile_options(fmt PRIVATE ${WERROR_FLAG})
+endif ()
 if (FMT_PEDANTIC)
   target_compile_options(fmt PRIVATE ${PEDANTIC_COMPILE_FLAGS})
 endif ()

appveyor.yml

@@ -0,0 +1 @@
+support/appveyor.yml

support/travis-build.py

@@ -86,12 +86,12 @@ test_build_dir = os.path.join(fmt_dir, "_build_test")
 # Configure library.
 makedirs_if_not_exist(build_dir)
 common_cmake_flags = [
-    '-DCMAKE_INSTALL_PREFIX=' + install_dir, '-DCMAKE_BUILD_TYPE=' + build
+    '-DCMAKE_INSTALL_PREFIX=' + install_dir, '-DCMAKE_BUILD_TYPE=' + build,
 ]
 extra_cmake_flags = []
 if standard != '14':
     extra_cmake_flags = ['-DCMAKE_CXX_FLAGS=-std=c++' + standard]
-check_call(['cmake', '-DFMT_DOC=OFF', '-DFMT_PEDANTIC=ON', fmt_dir] +
+check_call(['cmake', '-DFMT_DOC=OFF', '-DFMT_PEDANTIC=ON', '-DFMT_WERROR=ON', fmt_dir] +
            common_cmake_flags + extra_cmake_flags, cwd=build_dir)
 
 # Build library.