watch: UTF-8 support broken

[zeha]

Bug reports:

The watch binary from the watch formula on Sierra fails to display non-ASCII characters (i.e. UTF-8 umlauts, etc.). As this works on Linux, I'd say this is a build environment issue.

Installed from watch-3.3.12.sierra.bottle.tar.gz, also happens when installing with brew install --HEAD watch.

Repro:

cat > ~/test.sh <<EOT
echo "höllö!" 
EOT

watch -n2 bash ~/test.sh

Notice that the displayed string is either "hllo!" or "h ll o!" depending on your Terminal.app settings, but never the expected "höllö!".

[MikeMcQuaid]

Does it work when built from source outside of Homebrew on macOS?

[apjanke]

I can reproduce zeha's issue. Doesn't work for me when built outside Homebrew either.

I think the issue is that its configure logic doesn't recognize macOS's ncurses library as providing wide character support, even though it does, and assumes a separate ncursesw library is required.

There's an --enable-watch8bit configure option which looks like it enables wide character support.

E.g., in watch.c:

#ifdef WITH_WATCH8BIT
# define _XOPEN_SOURCE_EXTENDED 1
# include <wchar.h>
# include <wctype.h>
#endif	/* WITH_WATCH8BIT */

However, when using that switch, configure fails. Looks like it's looking for a separate ncursesw library.

[~/tmp/procps-ng/procps on ⇄ master]
$ ./configure --prefix=/tmp/test-watch --enable-watch8bit
...
checking for NCURSES... no
checking for initscr in -lncurses... yes
checking for curses.h... yes
checking for ncurses.h... yes
checking for term.h... yes
checking for NCURSESW... no
checking for addwstr in -lncursesw... no
configure: error: Cannot find ncurses wide library ncursesw with --enable-watch8bit

Seems like basically the same upstream issue as hishamhm/htop#301.

If I modify the watch formula to have depends_on "homebrew/dupes/ncurses" (which does have a separate libncursesw) and add the --enable-watch8bit, then it builds, and UTF-8 display using OP's test code works for me.

Sounds like this should be reported upstream as an incompatibility with macOS's ncurses library.

[apjanke]

Reported upstream: https://gitlab.com/procps-ng/procps/issues/47

[MikeMcQuaid]

I can reproduce zeha's issue. Doesn't work for me when built outside Homebrew either.

Thanks @apjanke. Closing as not a Homebrew issue.