Merge pull request #2514 from thejcannon:msvc_macro_issue

googlemock/include/gmock/internal/gmock-pp.h

 #ifndef THIRD_PARTY_GOOGLETEST_GOOGLEMOCK_INCLUDE_GMOCK_PP_H_
 #define THIRD_PARTY_GOOGLETEST_GOOGLEMOCK_INCLUDE_GMOCK_PP_H_
 
-#undef GMOCK_PP_INTERNAL_USE_MSVC
-#if defined(__clang__)
-#define GMOCK_PP_INTERNAL_USE_MSVC 0
-#elif defined(_MSC_VER)
-// TODO(iserna): Also verify tradional versus comformant preprocessor.
-static_assert(
-    _MSC_VER >= 1900,
-    "MSVC version not supported. There is support for MSVC 14.0 and above.");
-#define GMOCK_PP_INTERNAL_USE_MSVC 1
-#else
-#define GMOCK_PP_INTERNAL_USE_MSVC 0
-#endif
-
 // Expands and concatenates the arguments. Constructed macros reevaluate.
 #define GMOCK_PP_CAT(_1, _2) GMOCK_PP_INTERNAL_CAT(_1, _2)
 
@@ -29,10 +16,6 @@ static_assert(
 // Returns the only argument.
 #define GMOCK_PP_IDENTITY(_1) _1
 
-// MSVC preprocessor collapses __VA_ARGS__ in a single argument, we use a
-// CAT-like directive to force correct evaluation. Each macro has its own.
-#if GMOCK_PP_INTERNAL_USE_MSVC
-
 // Evaluates to the number of arguments after expansion.
 //
 //   #define PAIR x, y
@@ -43,45 +26,27 @@ static_assert(
 //   GMOCK_PP_NARG(PAIR) => 2
 //
 // Requires: the number of arguments after expansion is at most 15.
-#define GMOCK_PP_NARG(...)                                                    \
-  GMOCK_PP_INTERNAL_NARG_CAT(                                                 \
-      GMOCK_PP_INTERNAL_INTERNAL_16TH(__VA_ARGS__, 15, 14, 13, 12, 11, 10, 9, \
-                                      8, 7, 6, 5, 4, 3, 2, 1), )
+#define GMOCK_PP_NARG(...) \
+  GMOCK_PP_INTERNAL_16TH(  \
+      (__VA_ARGS__, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1))
 
 // Returns 1 if the expansion of arguments has an unprotected comma. Otherwise
 // returns 0. Requires no more than 15 unprotected commas.
-#define GMOCK_PP_HAS_COMMA(...)                                               \
-  GMOCK_PP_INTERNAL_HAS_COMMA_CAT(                                            \
-      GMOCK_PP_INTERNAL_INTERNAL_16TH(__VA_ARGS__, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
-                                      1, 1, 1, 1, 1, 0), )
+#define GMOCK_PP_HAS_COMMA(...) \
+  GMOCK_PP_INTERNAL_16TH(       \
+      (__VA_ARGS__, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0))
+
 // Returns the first argument.
-#define GMOCK_PP_HEAD(...) \
-  GMOCK_PP_INTERNAL_HEAD_CAT(GMOCK_PP_INTERNAL_HEAD(__VA_ARGS__), )
+#define GMOCK_PP_HEAD(...) GMOCK_PP_INTERNAL_HEAD((__VA_ARGS__))
 
 // Returns the tail. A variadic list of all arguments minus the first. Requires
 // at least one argument.
-#define GMOCK_PP_TAIL(...) \
-  GMOCK_PP_INTERNAL_TAIL_CAT(GMOCK_PP_INTERNAL_TAIL(__VA_ARGS__), )
+#define GMOCK_PP_TAIL(...) GMOCK_PP_INTERNAL_TAIL((__VA_ARGS__))
 
 // Calls CAT(_Macro, NARG(__VA_ARGS__))(__VA_ARGS__)
 #define GMOCK_PP_VARIADIC_CALL(_Macro, ...) \
-  GMOCK_PP_INTERNAL_VARIADIC_CALL_CAT(      \
-      GMOCK_PP_CAT(_Macro, GMOCK_PP_NARG(__VA_ARGS__))(__VA_ARGS__), )
-
-#else  // GMOCK_PP_INTERNAL_USE_MSVC
-
-#define GMOCK_PP_NARG(...)                                                   \
-  GMOCK_PP_INTERNAL_INTERNAL_16TH(__VA_ARGS__, 15, 14, 13, 12, 11, 10, 9, 8, \
-                                  7, 6, 5, 4, 3, 2, 1)
-#define GMOCK_PP_HAS_COMMA(...)                                              \
-  GMOCK_PP_INTERNAL_INTERNAL_16TH(__VA_ARGS__, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
-                                  1, 1, 1, 1, 0)
-#define GMOCK_PP_HEAD(...) GMOCK_PP_INTERNAL_HEAD(__VA_ARGS__)
-#define GMOCK_PP_TAIL(...) GMOCK_PP_INTERNAL_TAIL(__VA_ARGS__)
-#define GMOCK_PP_VARIADIC_CALL(_Macro, ...) \
-  GMOCK_PP_CAT(_Macro, GMOCK_PP_NARG(__VA_ARGS__))(__VA_ARGS__)
-
-#endif  // GMOCK_PP_INTERNAL_USE_MSVC
+  GMOCK_PP_IDENTITY(                        \
+      GMOCK_PP_CAT(_Macro, GMOCK_PP_NARG(__VA_ARGS__))(__VA_ARGS__))
 
 // If the arguments after expansion have no tokens, evaluates to `1`. Otherwise
 // evaluates to `0`.
@@ -139,10 +104,9 @@ static_assert(
 
 // Expands to 1 if the first argument starts with something in parentheses,
 // otherwise to 0.
-#define GMOCK_PP_IS_BEGIN_PARENS(...)                    \
-  GMOCK_PP_INTERNAL_ALTERNATE_HEAD(                      \
-      GMOCK_PP_CAT(GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_R_, \
-                   GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_C __VA_ARGS__))
+#define GMOCK_PP_IS_BEGIN_PARENS(...)                              \
+  GMOCK_PP_HEAD(GMOCK_PP_CAT(GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_R_, \
+                             GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_C __VA_ARGS__))
 
 // Expands to 1 is there is only one argument and it is enclosed in parentheses.
 #define GMOCK_PP_IS_ENCLOSED_PARENS(...)             \
@@ -179,10 +143,6 @@ static_assert(
 #define GMOCK_PP_INTENRAL_EMPTY_TUPLE (, , , , , , , , , , , , , , , )
 #define GMOCK_PP_INTERNAL_CAT(_1, _2) _1##_2
 #define GMOCK_PP_INTERNAL_STRINGIZE(...) #__VA_ARGS__
-#define GMOCK_PP_INTERNAL_INTERNAL_16TH(_1, _2, _3, _4, _5, _6, _7, _8, _9, \
-                                        _10, _11, _12, _13, _14, _15, _16,  \
-                                        ...)                                \
-  _16
 #define GMOCK_PP_INTERNAL_CAT_5(_1, _2, _3, _4, _5) _1##_2##_3##_4##_5
 #define GMOCK_PP_INTERNAL_IS_EMPTY(_1, _2, _3, _4)                             \
   GMOCK_PP_HAS_COMMA(GMOCK_PP_INTERNAL_CAT_5(GMOCK_PP_INTERNAL_IS_EMPTY_CASE_, \
@@ -190,30 +150,24 @@ static_assert(
 #define GMOCK_PP_INTERNAL_IS_EMPTY_CASE_0001 ,
 #define GMOCK_PP_INTERNAL_IF_1(_Then, _Else) _Then
 #define GMOCK_PP_INTERNAL_IF_0(_Then, _Else) _Else
-#define GMOCK_PP_INTERNAL_HEAD(_1, ...) _1
-#define GMOCK_PP_INTERNAL_TAIL(_1, ...) __VA_ARGS__
 
-#if GMOCK_PP_INTERNAL_USE_MSVC
-#define GMOCK_PP_INTERNAL_NARG_CAT(_1, _2) GMOCK_PP_INTERNAL_NARG_CAT_I(_1, _2)
-#define GMOCK_PP_INTERNAL_HEAD_CAT(_1, _2) GMOCK_PP_INTERNAL_HEAD_CAT_I(_1, _2)
-#define GMOCK_PP_INTERNAL_HAS_COMMA_CAT(_1, _2) \
-  GMOCK_PP_INTERNAL_HAS_COMMA_CAT_I(_1, _2)
-#define GMOCK_PP_INTERNAL_TAIL_CAT(_1, _2) GMOCK_PP_INTERNAL_TAIL_CAT_I(_1, _2)
-#define GMOCK_PP_INTERNAL_VARIADIC_CALL_CAT(_1, _2) \
-  GMOCK_PP_INTERNAL_VARIADIC_CALL_CAT_I(_1, _2)
-#define GMOCK_PP_INTERNAL_NARG_CAT_I(_1, _2) _1##_2
-#define GMOCK_PP_INTERNAL_HEAD_CAT_I(_1, _2) _1##_2
-#define GMOCK_PP_INTERNAL_HAS_COMMA_CAT_I(_1, _2) _1##_2
-#define GMOCK_PP_INTERNAL_TAIL_CAT_I(_1, _2) _1##_2
-#define GMOCK_PP_INTERNAL_VARIADIC_CALL_CAT_I(_1, _2) _1##_2
-#define GMOCK_PP_INTERNAL_ALTERNATE_HEAD(...) \
-  GMOCK_PP_INTERNAL_ALTERNATE_HEAD_CAT(GMOCK_PP_HEAD(__VA_ARGS__), )
-#define GMOCK_PP_INTERNAL_ALTERNATE_HEAD_CAT(_1, _2) \
-  GMOCK_PP_INTERNAL_ALTERNATE_HEAD_CAT_I(_1, _2)
-#define GMOCK_PP_INTERNAL_ALTERNATE_HEAD_CAT_I(_1, _2) _1##_2
-#else  // GMOCK_PP_INTERNAL_USE_MSVC
-#define GMOCK_PP_INTERNAL_ALTERNATE_HEAD(...) GMOCK_PP_HEAD(__VA_ARGS__)
-#endif  // GMOCK_PP_INTERNAL_USE_MSVC
+// Because of MSVC treating a token with a comma in it as a single token when
+// passed to another macro, we need to force it to evaluate it as multiple
+// tokens. We do that by using a "IDENTITY(MACRO PARENTHESIZED_ARGS)" macro. We
+// define one per possible macro that relies on this behavior. Note "_Args" must
+// be parenthesized.
+#define GMOCK_PP_INTERNAL_INTERNAL_16TH(_1, _2, _3, _4, _5, _6, _7, _8, _9, \
+                                        _10, _11, _12, _13, _14, _15, _16,  \
+                                        ...)                                \
+  _16
+#define GMOCK_PP_INTERNAL_16TH(_Args) \
+  GMOCK_PP_IDENTITY(GMOCK_PP_INTERNAL_INTERNAL_16TH _Args)
+#define GMOCK_PP_INTERNAL_INTERNAL_HEAD(_1, ...) _1
+#define GMOCK_PP_INTERNAL_HEAD(_Args) \
+  GMOCK_PP_IDENTITY(GMOCK_PP_INTERNAL_INTERNAL_HEAD _Args)
+#define GMOCK_PP_INTERNAL_INTERNAL_TAIL(_1, ...) __VA_ARGS__
+#define GMOCK_PP_INTERNAL_TAIL(_Args) \
+  GMOCK_PP_IDENTITY(GMOCK_PP_INTERNAL_INTERNAL_TAIL _Args)
 
 #define GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_C(...) 1 _
 #define GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_R_1 1,

googlemock/test/gmock-pp_test.cc

 #include "gmock/internal/gmock-pp.h"
 
+// Used to test MSVC treating __VA_ARGS__ with a comma in it as one value
+#define GMOCK_TEST_REPLACE_comma_WITH_COMMA_I_comma ,
+#define GMOCK_TEST_REPLACE_comma_WITH_COMMA(x) \
+  GMOCK_PP_CAT(GMOCK_TEST_REPLACE_comma_WITH_COMMA_I_, x)
+
 // Static assertions.
 namespace testing {
 namespace internal {
@@ -17,6 +22,11 @@ static_assert(GMOCK_PP_NARG(x, y, z, w) == 4, "");
 static_assert(!GMOCK_PP_HAS_COMMA(), "");
 static_assert(GMOCK_PP_HAS_COMMA(b, ), "");
 static_assert(!GMOCK_PP_HAS_COMMA((, )), "");
+static_assert(GMOCK_PP_HAS_COMMA(GMOCK_TEST_REPLACE_comma_WITH_COMMA(comma)),
+              "");
+static_assert(
+    GMOCK_PP_HAS_COMMA(GMOCK_TEST_REPLACE_comma_WITH_COMMA(comma(unrelated))),
+    "");
 static_assert(!GMOCK_PP_IS_EMPTY(, ), "");
 static_assert(!GMOCK_PP_IS_EMPTY(a), "");
 static_assert(!GMOCK_PP_IS_EMPTY(()), "");