PATCH: Link with curses if (and even) if it doesn't provide tgetent

PATCH: Link with curses if (and even) if it doesn't provide tgetent

[Sebastian Gniazdowski]

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Hello,
I've noticed that on Gentoo the zsh built doesn't include the curses
module. Closer look revealed the cause: the ncurses libraries
(ncursesw and ncurses) don't provide the call tgetent (nor tigetflag),
only tinfo does provide it. I guess this is the next step in splitting
libtinfo out of ncurses.

But this means that the binary can be linked to both ncurses and
tinfo. I've also checked that linking against such tgetent-lacking
ncurses and termcap works with no problems.

The patch does:
- it allows the normal flow of the checks with no changes,
- in the "if we need to ignore ncurses" check it adds, in case of
positive resolution of the test, an additional check that verifies for
initscr() in any of ncursesw, ncurses, curses and if this check is
positive, it then allows to link against that found curses library,
- it also adds libtinfow (side to libtinfo) to the terminal libraries
searched, as such library exists on the Gentoo system.

This way the zsh/curses module builds OK.

I attach the git-format-patch file.
-- 
Sebastian Gniazdowski
News: https://twitter.com/ZdharmaI
IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
Blog: http://zdharma.org

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From e56bf700acaf4a50143daec16208ab86c8586f9c Mon Sep 17 00:00:00 2001
From: Sebastian Gniazdowski <sgniazdowski@gmail.com>
Date: Thu, 3 Oct 2019 15:54:17 +0200
Subject: [PATCH] configure: Link with ncurses if (and even) it doesn't provide
 tgetent, to build the module. Also link with tinfow (not only tinfo)

---
 configure.ac | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index b31b1d958..c33188561 100644
--- a/configure.ac
+++ b/configure.ac
@@ -774,7 +774,7 @@ AS_HELP_STRING([--with-term-lib=LIBS],[search space-separated LIBS for terminal
   termcap_curses_order="$withval"
   AC_SEARCH_LIBS(tigetstr, [$termcap_curses_order])
 else
-  termcap_curses_order="$ncursesw_test $ncurses_test tinfo termcap curses"
+  termcap_curses_order="$ncursesw_test $ncurses_test tinfow tinfo termcap curses"
 fi],
 [case "$host_os" in
   solaris*)
@@ -783,7 +783,7 @@ fi],
    DL_EXT="${DL_EXT=sl}"
    termcap_curses_order="Hcurses $ncursesw_test $ncurses_test curses termcap" ;;
   *)
-   termcap_curses_order="$ncursesw_test $ncurses_test tinfo termcap curses" ;;
+   termcap_curses_order="$ncursesw_test $ncurses_test tinfow tinfo termcap curses" ;;
 esac])dnl
 
 AH_TEMPLATE([ZSH_NO_XOPEN],
@@ -831,7 +831,18 @@ AC_CACHE_CHECK(if we need to ignore ncurses, zsh_cv_ignore_ncurses,
   zsh_cv_ignore_ncurses=no
   ;;
   *)
-  zsh_cv_ignore_ncurses=yes
+    dnl If the tgetent nor tigetflag weren't found in the libncurses*.so, then
+    dnl there will be no conflict with the other terminal library selected (e.g.
+    dnl libtinfo) and it's possible to link ncurses provided that it is working
+    AC_SEARCH_LIBS(initscr, [ncursesw ncurses curses])
+    case $LIBS in
+      *-lncurses*|*-lcurses*)
+      zsh_cv_ignore_ncurses=no
+      ;;
+      *)
+      zsh_cv_ignore_ncurses=yes
+      ;;
+    esac
   ;;
 esac])
 
-- 
2.21.0

Re: PATCH: Link with curses if (and even) if it doesn't provide tgetent

[Sebastian Gniazdowski]

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Hello,
I've revised the patch. It has been seriously upgraded:
- the checks against the termcap & terminfo functions is being ran
again explicitly before deciding to link with ncurses,
- more functions are being checked, namely all that I've found tests
in the configure for, i.e.: besides tgetent and tigetflag, also
tigetstr and tigetnum,
- I've also extended the normal- i.e.: previous test with the tigetstr
function, as it seems to be most important, because it's the function
that's being tested for when --with-term-lib=... is being used.

Besides, the update adding tinfow to the searched libs is preserved.

I think that the patch is important. Ncurses is being drilled out of
termcap & terminfo functions, and this means that the zsh/curses
module will never be built.

On Thu, 3 Oct 2019 at 16:39, Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
>
> Hello,
> I've noticed that on Gentoo the zsh built doesn't include the curses
> module. Closer look revealed the cause: the ncurses libraries
> (ncursesw and ncurses) don't provide the call tgetent (nor tigetflag),
> only tinfo does provide it. I guess this is the next step in splitting
> libtinfo out of ncurses.
>
> But this means that the binary can be linked to both ncurses and
> tinfo. I've also checked that linking against such tgetent-lacking
> ncurses and termcap works with no problems.
>
> The patch does:
> - it allows the normal flow of the checks with no changes,
> - in the "if we need to ignore ncurses" check it adds, in case of
> positive resolution of the test, an additional check that verifies for
> initscr() in any of ncursesw, ncurses, curses and if this check is
> positive, it then allows to link against that found curses library,
> - it also adds libtinfow (side to libtinfo) to the terminal libraries
> searched, as such library exists on the Gentoo system.
>
> This way the zsh/curses module builds OK.
>
> I attach the git-format-patch file.
> --
> Sebastian Gniazdowski
> News: https://twitter.com/ZdharmaI
> IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
> Blog: http://zdharma.org



-- 
Sebastian Gniazdowski
News: https://twitter.com/ZdharmaI
IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
Blog: http://zdharma.org

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From 5b7d43abe3f01d3a72301f9b44faf28cafe5da27 Mon Sep 17 00:00:00 2001
From: Sebastian Gniazdowski <sgniazdowski@gmail.com>
Date: Wed, 23 Oct 2019 19:06:40 +0200
Subject: [PATCH] =?UTF-8?q?configure=20=E2=80=93=C2=A0Try=20to=20link=20wi?=
 =?UTF-8?q?th=20a=20curses=20library=20if=20it=20doesn't=20contain=20the?=
 =?UTF-8?q?=20tercamp=20&=20terminfo=20functions?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 configure.ac | 57 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index b31b1d958..8fd4d452f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -774,7 +774,7 @@ AS_HELP_STRING([--with-term-lib=LIBS],[search space-separated LIBS for terminal
   termcap_curses_order="$withval"
   AC_SEARCH_LIBS(tigetstr, [$termcap_curses_order])
 else
-  termcap_curses_order="$ncursesw_test $ncurses_test tinfo termcap curses"
+  termcap_curses_order="$ncursesw_test $ncurses_test tinfow tinfo termcap curses"
 fi],
 [case "$host_os" in
   solaris*)
@@ -783,7 +783,7 @@ fi],
    DL_EXT="${DL_EXT=sl}"
    termcap_curses_order="Hcurses $ncursesw_test $ncurses_test curses termcap" ;;
   *)
-   termcap_curses_order="$ncursesw_test $ncurses_test tinfo termcap curses" ;;
+   termcap_curses_order="$ncursesw_test $ncurses_test tinfow tinfo termcap curses" ;;
 esac])dnl
 
 AH_TEMPLATE([ZSH_NO_XOPEN],
@@ -807,6 +807,8 @@ dnl That's so that on systems where termcap and [n]curses are
 dnl both available and both contain termcap functions, while
 dnl only [n]curses contains terminfo functions, we only link against
 dnl [n]curses.
+LIBS_save_pre_term="$LIBS"
+AC_SEARCH_LIBS(tigetstr, [$termcap_curses_order])
 AC_SEARCH_LIBS(tigetflag, [$termcap_curses_order])
 AC_SEARCH_LIBS(tgetent, [$termcap_curses_order],
   true,
@@ -831,7 +833,56 @@ AC_CACHE_CHECK(if we need to ignore ncurses, zsh_cv_ignore_ncurses,
   zsh_cv_ignore_ncurses=no
   ;;
   *)
-  zsh_cv_ignore_ncurses=yes
+    dnl The lack of -lncurses in the $LIBS might be the result of passing
+    dnl --with-term-lib=^ncurses option. To address this, a test for the tgetent
+    dnl and other functions is ran here, possibly for the second time, just to
+    dnl ensure that the ncurses library doesn't have them.
+    LIBS_save="$LIBS"
+    dnl Remember (the values are used later, around line 3005) and remove the cache
+    ac_cv_search_tigetstr_SAVE="$ac_cv_search_tigetstr"
+    ac_cv_search_tigetnum_SAVE="$ac_cv_search_tigetnum"
+    ac_cv_search_tigetflag_SAVE="$ac_cv_search_tigetflag"
+    ac_cv_search_tgetent_SAVE="$ac_cv_search_tgetent"
+    unset ac_cv_search_tigetstr ac_cv_search_tigetnum ac_cv_search_tigetflag ac_cv_search_tgetent
+    LIBS="$LIBS_save_pre_term"
+
+    dnl Run the checks for all four used terminal functions
+    AC_SEARCH_LIBS(tigetstr, [ncursesw ncurses curses])
+    AC_SEARCH_LIBS(tigetnum, [ncursesw ncurses curses])
+    AC_SEARCH_LIBS(tigetflag, [ncursesw ncurses curses])
+    AC_SEARCH_LIBS(tgetent, [ncursesw ncurses curses])
+    LIBS_result="$LIBS"
+
+    LIBS="$LIBS_save"
+    dnl Restore the cache
+    ac_cv_search_tigetstr="$ac_cv_search_tigetstr_SAVE"
+    ac_cv_search_tigetnum="$ac_cv_search_tigetnum_SAVE"
+    ac_cv_search_tigetflag="$ac_cv_search_tigetflag_SAVE"
+    ac_cv_search_tgetent="$ac_cv_search_tgetent_SAVE"
+
+    case $LIBS_result in
+      *-lncurses*|*-lcurses*)
+        dnl Yes we need to ignore ncurses, its tgetent or tigetflag might
+        dnl conflict with the one from the selected terminal library
+        zsh_cv_ignore_ncurses=yes
+        ;;
+      *)
+        dnl If the tgetent nor tigetflag weren't found in the libncurses*.so, then
+        dnl there will be no conflict with the other terminal library selected (e.g.
+        dnl libtinfo) and it's possible to link ncurses provided that it is working
+        dnl - it is here verified that it has initscr() function to check that
+        AC_SEARCH_LIBS(initscr, [ncursesw ncurses curses])
+        case $LIBS in
+          *-lncurses*|*-lcurses*)
+            dnl No need to ignore curses - it is working and it doesn't
+            dnl have tgetent nor tigetflag
+            zsh_cv_ignore_ncurses=no
+          ;;
+          *)
+            zsh_cv_ignore_ncurses=yes
+          ;;
+        esac
+    esac
   ;;
 esac])
 
-- 
2.21.0

Re: PATCH: Link with curses if (and even) if it doesn't provide tgetent

[Peter Stephenson]

On Wed, 2019-10-23 at 19:18 +0200, Sebastian Gniazdowski wrote:
> Hello,
> I've revised the patch. It has been seriously upgraded:
> - the checks against the termcap & terminfo functions is being ran
> again explicitly before deciding to link with ncurses,
> - more functions are being checked, namely all that I've found tests
> in the configure for, i.e.: besides tgetent and tigetflag, also
> tigetstr and tigetnum,
> - I've also extended the normal- i.e.: previous test with the tigetstr
> function, as it seems to be most important, because it's the function
> that's being tested for when --with-term-lib=... is being used.

Looks plausible --- we'll probably only find problems if we roll it out.
Hopefully enough people will try it to get some coverage.  I'll commit
this if no one spots anything.

pws