Re: Unused header file inclusion

I wrote:
> (My headerscheck script is missing that header; I need to update it to
> match the latest version of cpluspluscheck.)

I did that, and ended up with the attached.  I'm rather tempted to stick
this into src/tools/ alongside cpluspluscheck, because it seems to find
rather different trouble spots than cpluspluscheck does.  Thoughts?

As of HEAD (927f34ce8), I get clean passes from both this and
cpluspluscheck, except for the FmgrInfo references in selfuncs.h.
I tried it on RHEL/Fedora, FreeBSD 12, and current macOS.

            regards, tom lane

#!/bin/sh

# Check (almost) all PostgreSQL include files for standalone build.
#
# Argument 1 is the top-level source directory, argument 2 the
# top-level build directory (they might be the same). If not set, they
# default to the current directory.
#
# Needs to be run after configuring and creating all generated headers.
# It's advisable to configure --with-perl --with-python, or you're
# likely to get errors from associated headers.
#
# No output if everything is OK, else compiler errors.

if [ -z "$1" ]; then
    srcdir="."
else
    srcdir="$1"
fi

if [ -z "$2" ]; then
    builddir="."
else
    builddir="$2"
fi

me=`basename $0`

# Pull some info from configure's results.
MGLOB="$builddir/src/Makefile.global"
CFLAGS=`sed -n 's/^CFLAGS[     ]*=[     ]*//p' "$MGLOB"`
CPPFLAGS=`sed -n 's/^CPPFLAGS[     ]*=[     ]*//p' "$MGLOB"`
PG_SYSROOT=`sed -n 's/^PG_SYSROOT[     ]*=[     ]*//p' "$MGLOB"`
CC=`sed -n 's/^CC[     ]*=[     ]*//p' "$MGLOB"`
perl_includespec=`sed -n 's/^perl_includespec[     ]*=[     ]*//p' "$MGLOB"`
python_includespec=`sed -n 's/^python_includespec[     ]*=[     ]*//p' "$MGLOB"`

# needed on Darwin
CPPFLAGS=`echo "$CPPFLAGS" | sed "s|\\$(PG_SYSROOT)|$PG_SYSROOT|g"`

# (EXTRAFLAGS is not set here, but user can pass it in if need be.)

# Create temp directory.
tmp=`mktemp -d /tmp/$me.XXXXXX`

trap 'rm -rf $tmp' 0 1 2 3 15

# Scan all of src/ and contrib/ for header files.
for f in `cd "$srcdir" && find src contrib -name '*.h' -print`
do
    # Ignore files that are unportable or intentionally not standalone.

    # These files are platform-specific, and c.h will include the
    # one that's relevant for our current platform anyway.
    test "$f" = src/include/port/aix.h && continue
    test "$f" = src/include/port/cygwin.h && continue
    test "$f" = src/include/port/darwin.h && continue
    test "$f" = src/include/port/freebsd.h && continue
    test "$f" = src/include/port/hpux.h && continue
    test "$f" = src/include/port/linux.h && continue
    test "$f" = src/include/port/netbsd.h && continue
    test "$f" = src/include/port/openbsd.h && continue
    test "$f" = src/include/port/solaris.h && continue
    test "$f" = src/include/port/win32.h && continue

    # Additional Windows-specific headers.
    test "$f" = src/include/port/win32_port.h && continue
    test "$f" = src/include/port/win32/sys/socket.h && continue
    test "$f" = src/include/port/win32_msvc/dirent.h && continue
    test "$f" = src/port/pthread-win32.h && continue

    # Likewise, these files are platform-specific, and the one
    # relevant to our platform will be included by atomics.h.
    test "$f" = src/include/port/atomics/arch-arm.h && continue
    test "$f" = src/include/port/atomics/arch-hppa.h && continue
    test "$f" = src/include/port/atomics/arch-ia64.h && continue
    test "$f" = src/include/port/atomics/arch-ppc.h && continue
    test "$f" = src/include/port/atomics/arch-x86.h && continue
    test "$f" = src/include/port/atomics/fallback.h && continue
    test "$f" = src/include/port/atomics/generic.h && continue
    test "$f" = src/include/port/atomics/generic-acc.h && continue
    test "$f" = src/include/port/atomics/generic-gcc.h && continue
    test "$f" = src/include/port/atomics/generic-msvc.h && continue
    test "$f" = src/include/port/atomics/generic-sunpro.h && continue
    test "$f" = src/include/port/atomics/generic-xlc.h && continue

    # rusagestub.h is also platform-specific, and will be included
    # by utils/pg_rusage.h if necessary.
    test "$f" = src/include/rusagestub.h && continue

    # sepgsql.h depends on headers that aren't there on most platforms.
    test "$f" = contrib/sepgsql/sepgsql.h && continue

    # These files are not meant to be included standalone, because
    # they contain lists that might have multiple use-cases.
    test "$f" = src/include/access/rmgrlist.h && continue
    test "$f" = src/include/parser/kwlist.h && continue
    test "$f" = src/pl/plpgsql/src/pl_reserved_kwlist.h && continue
    test "$f" = src/pl/plpgsql/src/pl_unreserved_kwlist.h && continue
    test "$f" = src/interfaces/ecpg/preproc/c_kwlist.h && continue
    test "$f" = src/interfaces/ecpg/preproc/ecpg_kwlist.h && continue
    test "$f" = src/include/regex/regerrs.h && continue
    test "$f" = src/pl/plpgsql/src/plerrcodes.h && continue
    test "$f" = src/pl/plpython/spiexceptions.h && continue
    test "$f" = src/pl/tcl/pltclerrcodes.h && continue

    # We can't make these Bison output files compilable standalone
    # without using "%code require", which old Bison versions lack.
    # parser/gram.h will be included by parser/gramparse.h anyway.
    test "$f" = src/include/parser/gram.h && continue
    test "$f" = src/backend/parser/gram.h && continue
    test "$f" = src/pl/plpgsql/src/pl_gram.h && continue
    test "$f" = src/interfaces/ecpg/preproc/preproc.h && continue

    # This produces a "no previous prototype" warning.
    test "$f" = src/include/storage/checksum_impl.h && continue

    # ppport.h is not under our control, so we can't make it standalone.
    test "$f" = src/pl/plperl/ppport.h && continue

    # regression.h is not actually C, but ECPG code.
    test "$f" = src/interfaces/ecpg/test/regression.h && continue
    # printf_hack.h produces "unused function" warnings.
    test "$f" = src/interfaces/ecpg/test/printf_hack.h && continue

    # OK, create .c file to include this .h file.
    {
        test "$f" != src/include/postgres_fe.h && echo '#include "postgres.h"'
        echo "#include \"$f\""
    } >$tmp/test.c

    # Some subdirectories need extra -I switches.
    case "$f" in
        src/pl/plperl/*)
        EXTRAINCLUDES="$perl_includespec" ;;
        src/pl/plpython/*)
        EXTRAINCLUDES="$python_includespec" ;;
        src/interfaces/ecpg/*)
        EXTRAINCLUDES="-I $builddir/src/interfaces/ecpg/include -I $srcdir/src/interfaces/ecpg/include" ;;
        *)
        EXTRAINCLUDES="" ;;
    esac

    # Run the test.
    ${CC:-gcc} $CPPFLAGS $CFLAGS -I $builddir -I $srcdir \
        -I $builddir/src/include -I $srcdir/src/include \
        -I $builddir/src/interfaces/libpq -I $srcdir/src/interfaces/libpq \
        $EXTRAINCLUDES $EXTRAFLAGS -c $tmp/test.c -o $tmp/test.o

done