[Bug preprocessor/17110] New: #include_next fails following #include that specifies an absolute path

["wb at fnal dot gov" <gcc-bugzilla at gcc dot gnu dot org>]

This bug first manifested for us using gcc 3.4.1 on each of multiple platforms;
it appears to be a regression from each previous gcc 3.x we have tried.

Specifically: an incorrect diagnostic ("no include path in which to search for
...") is produced under the following circumstances:

  File_A contains #include "/absolute/path/to/File_B"
and
  File_B contains #include_next "File_C"

Note that this failure only arises when an absolute path is specified in
Fila_A's #include.

The failure manifests when compiling via gcc as well as via g++.

The failure seems not to depend on the form of the command line -I; it does not
matter whether the directory there specified is part of a relative path or is
part of an absolute path.

A test case follows; there are 5 tiny files to be spread across 3 directories. 
Because there is an absolute path involved, you will need to edit one line (in
test/test.cc) to reflect your local directory tree.

Thanks for looking into this; it's a real show-stopper for us in moving to gcc
3.4.1.  Best,

-- WEB


==========  test/compile  ==========
#!/bin/sh

go()  {
  rm -f a.out

  ( gcc test.cc -o a.out -Inext -D$1\
    && ./a.out\
    && echo Success\
  )\
    || echo Failure!;
}

echo "V1: #include \"inc/next.cc\""
go V1

echo "V2: #include \"./inc/next.cc\""
go V2

echo "V3: #include \"/complete/path/to/inc/next.cc\""
go V3


==========  test/test.cc  ==========
#if defined V1 // works
#include "inc/next.cc"

#elif defined V2 // works
#include "./inc/next.cc"

#else  // EDIT THE NEXT LINE PER YOUR SETUP; FAILS!
#include "/complete/path/to/test/inc/next.cc"

#endif


==========  test/inc/next.h  ==========
//   Note: this header ought be located in the same directory as the
//   next.cc test program; if the directive functions properly, this
//   header will not be #include'd

#error "got wrong <incnext.hh>"


==========  test/inc/next.cc  ==========\
#define RESULT  1

#include_next "next.h"

int  main()
{
  return  RESULT;
}


==========  test/next/next.h  ==========
//   If the directive functions properly, this header
//   will be located instead of the one (by the same name) in the same
//   directory as the next.cc test program

#ifdef RESULT
  #undef RESULT
#endif

#define RESULT 0

-- 
           Summary: #include_next fails following #include that specifies an
                    absolute path
           Product: gcc
           Version: 3.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P1
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: wb at fnal dot gov
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17110