sign-compare compiler warning

[cgzones]

https://github.com/westes/flex/blob/master/src/flex.skl#L1781 is raising sign-compare warnings with flex 2.6.0 on debian sid for me:

gcc-5 / gcc-6:

<stdout>: In function ‘yy_get_next_buffer’:
<stdout>:1113:44: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

clang-3.8:

<stdout>:1113:44: warning: comparison of integers of different signs: 'int' and 'yy_size_t' (aka 'unsigned long') [-Wsign-compare]
        if ((int) ((yy_n_chars) + number_to_move) > YY_CURRENT_BUFFER_LVALUE->yy_buf_size) {

[westes]

This should be resolved in current master. Your report mentions 2.6.0, so please check this against the current tip of master.

[westes]

What flex are you using in the build of selinux?

On Friday, 26 February 2016, 10:25 am -0800, cgzones notifications@github.com wrote:

i still get the same warning (different line number) with the latest git.

my steps:

git clone https://github.com/westes/flex
cd flex/
./autogen.sh
./configure
make
cd ../

git clone https://github.com/SELinuxProject/selinux
cd selinux/
make DESTDIR=$(pwd)/build install

result:

cc -Werror -Wall -W -Wundef -Wshadow -Wmissing-format-attribute -O2 -I. -I../include -D_GNU_SOURCE -I../cil/include -fPIC -c -o ../cil/src/cil_lexer.o ../cil/src/cil_lexer.c
<stdout>: In function ‘yy_get_next_buffer’:
<stdout>:1113:44: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

---

Reply to this email directly or view it on GitHub:
#61 (comment)

Will Estes
westes575@gmail.com

[cgzones]

i still get the same warning (different line number) with the latest git.

my steps:

git clone https://github.com/westes/flex
cd flex/
./autogen.sh
./configure
make
cd ../

git clone https://github.com/SELinuxProject/selinux
source='LEX = flex'
replace='LEX = ..\/..\/..\/flex\/src\/flex'
sed -i "s/${source}/${replace}/g" selinux/libsepol/src/Makefile
cd selinux/
make DESTDIR=$(pwd)/build install

result:

../../../flex/src/flex -t ../cil/src/cil_lexer.l > ../cil/src/cil_lexer.c
cc -Werror -Wall -W -Wundef -Wshadow -Wmissing-format-attribute -O2 -I. -I../include -D_GNU_SOURCE -I../cil/include -fPIC -c -o ../cil/src/cil_lexer.o ../cil/src/cil_lexer.c
<stdout>: In function ‘yy_get_next_buffer’:
<stdout>:1098:44: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

sorry, i posted a previous version of this post earlier, which used an old version of flex

[westes]

Thanks for the clarification. You should now see this compile. I get no output from the compilation command with the change I just committed and pushed.

[cgzones]

Thanks, it works now

[grahamc]

Hi @westes, can you provide a patch NixOS could apply to 2.6.1 to resolve this? We tried applying 3946924ed5e77420c453bf841603c7278766093abut it doesn't apply cleanly. We're finding we'll need to patch several packages with -Wno-error=sign-compare but would prefer applying a patch to flex itself.

/cc NixOS/nixpkgs#19129

[vcunat]

BTW, it's not just NixOS. I believe e.g. Debian (still) suffers from this as well on 2.6.1: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=835542#59

[RalphCorderoy]

Regarding the 2.6.1 problem, I've opened #97.

[df7cb]

I'll be pushing oftc@8d18a80 to Debian to fix this in 2.6.1.

[vcunat]

I just wonder, why not 2.6.3 directly?

[westes]

Because Debian likes to keep old obsolete versions around. That patch doesn't apply against 2.6.3 anyways.

…

On Friday, 30 December 2016, 3:42 pm -0800, Vladimír Čunát ***@***.***> wrote: I just wonder, why not 2.6.3 directly? -- You are receiving this because you were mentioned. Reply to this email directly or view it on GitHub: #61 (comment)

-- Will Estes westes575@gmail.com