"Conflict" between system-wide Googletest install and STP's (macOS)

[aytey]

Description of issue

On a fresh macOS Big Sur install, with Googletest installed installed via Mac Ports, I get errors such as:

../utils/gtest/src/gtest-internal-inl.h:428:11: error: unknown type name 'string'; did you mean 'String'?
  virtual string CurrentStackTrace(int max_depth, int skip_count) = 0;
          ^~~~~~
          String
/opt/local/include/gtest/internal/gtest-string.h:58:18: note: 'String' declared here
class GTEST_API_ String {
                 ^
In file included from ../utils/gtest/src/gtest-all.cc:42:
In file included from ../utils/gtest/src/gtest.cc:135:
../utils/gtest/src/gtest-internal-inl.h:444:11: error: unknown type name 'string'; did you mean 'String'?
  virtual string CurrentStackTrace(int max_depth, int skip_count)
          ^~~~~~
          String
/opt/local/include/gtest/internal/gtest-string.h:58:18: note: 'String' declared here
class GTEST_API_ String {
                 ^
In file included from ../utils/gtest/src/gtest-all.cc:42:
In file included from ../utils/gtest/src/gtest.cc:135:
../utils/gtest/src/gtest-internal-inl.h:644:25: error: no type named 'SetUpTestCaseFunc' in 'testing::Test'; did you mean 'SetUpTestSuiteFunc'?
                        Test::SetUpTestCaseFunc set_up_tc,
                        ^~~~~~~~~~~~~~~~~~~~~~~
                        SetUpTestSuiteFunc
/opt/local/include/gtest/internal/gtest-internal.h:477:7: note: 'SetUpTestSuiteFunc' declared here
using SetUpTestSuiteFunc = void (*)();
      ^

The reason for this is that zlib is installed via MacPorts, so ZLIB_INCLUDE_DIR gets expanded to /opt/local/include. If you have Googletest installed by MacPorts, then you also have gtest/gtest.h in /opt/local/include. Given that STP needs the zlib include dirs, the final compiler invocation looks like:

/Library/Developer/CommandLineTools/usr/bin/c++ \
    -DGTEST_CREATE_SHARED_LIBRARY=1 \
    -D__STDC_LIMIT_MACROS \
    -Dgtest_EXPORTS \
    -I../include \
    -Iinclude \
    -I../lib \
    -I/opt/local/include \               # <-- needed for zlib
    -I/Users/avj/clones/minisat \
    -I../utils/gtest/include \           # <-- needed for path to gtest submodule
    -I../utils/gtest \
    -g3 \
    -ggdb3 \
    -stdlib=libc++ \
    -Wall \
    -Wextra \
    -Wunused \
    -pedantic \
    -Wsign-compare \
    -fno-omit-frame-pointer \
    -Wtype-limits \
    -Wuninitialized \
    -Wno-deprecated \
    -Wstrict-aliasing \
    -Wpointer-arith \
    -Wheader-guard \
    -Wpointer-arith \
    -Wformat-nonliteral \
    -Winit-self \
    -Wparentheses \
    -Wunreachable-code \
    -O2 \
    -g \
    -arch \
    arm64 \
    -isysroot \
    /Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk \
    -fPIC \
    -g3 \
    -ggdb3 \
    -stdlib=libc++ \
    -Wall \
    -Wextra \
    -Wunused \
    -pedantic \
    -Wsign-compare \
    -fno-omit-frame-pointer \
    -Wtype-limits \
    -Wuninitialized \
    -Wno-deprecated \
    -Wstrict-aliasing \
    -Wpointer-arith \
    -Wheader-guard \
    -Wpointer-arith \
    -Wformat-nonliteral \
    -Winit-self \
    -Wparentheses \
    -Wunreachable-code \
    -DGTEST_HAS_PTHREAD=1 \
    -g \
    -pthread \
    -O2 \
    -fPIC \
    -std=gnu++14 \
    -MD \
    -MT \
    tests/gtest/CMakeFiles/gtest.dir/src/gtest-all.cc.o \
    -MF \
    tests/gtest/CMakeFiles/gtest.dir/src/gtest-all.cc.o.d \
    -o \
    tests/gtest/CMakeFiles/gtest.dir/src/gtest-all.cc.o \
    -c \
    ../utils/gtest/src/gtest-all.cc

(notice that /opt/local/include is before../utils/gtest/include).

However, inside of ../utils/gtest/src/gtest-all.cc, the code does this:

#include "gtest/gtest.h"

However, because ../utils/gtest/src/gtest/gtest.h does not exist (the correct path should be ../utils/gtest/include/gtest/gtest.h), this then means that we find gtest in /opt/local/include, which then clashes with what's in ../utils/gtest/include, leading to compilation errors.

Temporary workarounds

Temporary workaround 1 uninstall Googletest system-wide.

Temporary workaround 2 Add -DENABLE_TESTING:BOOL=OFF to your cmake invocation.