[core] Improve Include PATH handling & add test (#14753)

* [core] Improve Include PATH handling & add test

Should fix #10866

* [core] clang-format

core/base/src/TSystem.cxx

@@ -3041,27 +3041,29 @@ int TSystem::CompileMacro(const char *filename, Option_t *opt,
 
    // Calculate the -I lines
    TString includes = GetIncludePath();
+   includes.ReplaceAll("-I ", "-I");
    includes.Prepend(' ');
 
    {
       // I need to replace the -Isomerelativepath by -I../ (or -I..\ on NT)
-      TRegexp rel_inc(" -I[^\"/\\$%-][^:-]+");
+      TRegexp rel_inc(" -I[^\"/\\\\$\\%-][^:\\s]+");
       Int_t len,pos;
       pos = rel_inc.Index(includes,&len);
       while( len != 0 ) {
          TString sub = includes(pos,len);
          sub.Remove(0,3); // Remove ' -I'
          AssignAndDelete( sub, ConcatFileName( WorkingDirectory(), sub ) );
          sub.Prepend(" -I\"");
-         sub.Chop(); // Remove trailing space (i.e between the -Is ...
+         if (sub.EndsWith(" "))
+            sub.Chop(); // Remove trailing space (i.e between the -Is ...
          sub.Append("\" ");
          includes.Replace(pos,len,sub);
          pos = rel_inc.Index(includes,&len);
       }
    }
    {
-       // I need to replace the -I"somerelativepath" by -I"$cwd/ (or -I"$cwd\ on NT)
-      TRegexp rel_inc(" -I\"[^/\\$%-][^:-]+");
+      // I need to replace the -I"somerelativepath" by -I"$cwd/ (or -I"$cwd\ on NT)
+      TRegexp rel_inc(" -I\"[^/\\\\$\\%-][^:\\s]+");
       Int_t len,pos;
       pos = rel_inc.Index(includes,&len);
       while( len != 0 ) {

core/base/test/CMakeLists.txt

@@ -25,3 +25,6 @@ ROOT_ADD_GTEST(CoreBaseTests
   LIBRARIES ${extralibs} RIO Core)
 
 ROOT_ADD_GTEST(CoreErrorTests TErrorTests.cxx LIBRARIES Core)
+
+configure_file(Foo.C Foo.C COPYONLY)
+ROOT_ADD_GTEST(IncludePathTest IncludePathTest.cxx LIBRARIES Core)

core/base/test/Foo.C

@@ -0,0 +1,8 @@
+#include <iostream>
+
+class Foo {
+public:
+   Foo() { std::cout << "Foo" << std::endl; }
+   ~Foo() { std::cout << "~Foo" << std::endl; }
+   void f() { std::cout << "f" << std::endl; }
+};

core/base/test/IncludePathTest.cxx

@@ -0,0 +1,31 @@
+#include "gtest/gtest.h"
+#include "TSystem.h"
+
+#include <string>
+
+TEST(TSystem, IncludePath)
+{
+   ASSERT_TRUE(gSystem);
+
+   gSystem->AddIncludePath("-I /some/path/with-xin-it -I ./some/relative-path");
+   gSystem->AddIncludePath("-I %ROOTSYS%\\include -I ${ROOTSYS}/include");
+#ifdef WIN32
+   gSystem->AddIncludePath(
+      "-I \"C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Tools\\MSVC\\14.38.33130\\include\"");
+#endif
+
+   testing::internal::CaptureStderr();
+   gSystem->CompileMacro("Foo.C", "f");
+   std::cerr.flush();
+   std::string errors = testing::internal::GetCapturedStderr();
+
+   gSystem->Unload("Foo_C");
+   gSystem->CleanCompiledMacros();
+#ifdef WIN32
+   EXPECT_TRUE((errors.find("cl : Command line warning D9002 : ignoring unknown option ") == std::string::npos));
+   gSystem->Exec("del Foo_C*");
+#else
+   EXPECT_TRUE((errors.find("c++: error: unrecognized command line option ") == std::string::npos));
+   gSystem->Exec("rm -f Foo_C*");
+#endif
+}