ZSH Prompt with themes won't work properly under MC

[md2k]

Hi ,
I use oh-my-zsh for theming my prompt and most of the time i use theme 'agnoster'.
my prompt looks like:

echo $PS1
%{%f%b%k%}$(build_prompt)

echo $(build_prompt)
%{%K{black}%}%{%F{default}%} %(!.%{%F{yellow}%}.)%{%{%}%}yflerko%{%{%}%}@%{%{%}%}%m %{%K{blue}%F{black}%}%{%F{white}%} ~ %{%k%F{blue}%}%{%f%}
or inside git repo:
%{%K{black}%}%{%F{default}%} %(!.%{%F{yellow}%}.)%{%{%}%}yflerko%{%{%}%}@%{%{%}%}%m %{%K{blue}%F{black}%}%{%F{white}%} ~/git/md2k/paramiko %{%K{green}%F{blue}%}%{%F{black}%}  master %{%k%F{green}%}%{%f%}

without MC everything looks good, and MC when in subshell (by Ctrl+o) also all fine.
But inside MC prompt on startup shown correctly, but if i start switch folders it randomly disappearing.
I tried use dtrace (MacOS) but with it MC always show Prompt properly, so unable to catch what happened when MC wiping prompt.
Below what i can see for prompt realted output:

read(0x3, "\r\033[0m\033[27m\033[24m\033[J\033[39m\033[0m\033[49m\033[40m\033[39m \033[38;5;009myflerko\033[38;5;011m@\033[38;5;014mMD2K-MAC \033[44m\033[30m\356\202\260\033[37m ~/git/eBa\0", 0x80)        = 128 0
write(0x1, "\r\033[0m\033[27m\033[24m\033[J\033[39m\033[0m\033[49m\033[40m\033[39m \033[38;5;009myflerko\033[38;5;011m@\033[38;5;014mMD2K-MAC \033[44m\033[30m\356\202\260\033[37m ~/git/eBa\0", 0x80)       = 128 0
select(0x7, 0x7FFF59F847E0, 0x0, 0x0, 0x0)       = 1 0
read(0x3, "y \033[49m\033[34m\356\202\260\033[39m \033[K\033[?1h\033=\0", 0x80)      = 36 0
write(0x1, "y \033[49m\033[34m\356\202\260\033[39m \033[K\033[?1h\033=\0", 0x24)         = 36 0

Below how prompt looks if i comment function strip_ctrl_codes for prompt:

\033[62;3H0m.[27m.[24m.[J.[39m.[0m.[49m.[40m.[39m .[38;5;009myflerko.[38;5;011m@.[38;5;014mMD2K-MAC .[44m.[30m\356\202\260.[37m ~/git .[49m.[34m\356\202\260.[39m .[K.[?1h.=\033[81C\033[62;155H\0

Some info about gcc and others:

mc -V
GNU Midnight Commander 4.8.12
Built with GLib 2.40.0
Using the S-Lang library with terminfo database
With builtin Editor
With subshell support as default
With support for background operations
With mouse support on xterm
With internationalization support
With multiple codepages support
Virtual File Systems: cpiofs, tarfs, sfs, extfs, ftpfs, sftpfs, fish, smbfs
Data types: char: 8; int: 32; long: 64; void *: 64; size_t: 64; off_t: 64;

gcc --version
Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.3.0
Thread model: posix

S-Lang version: 2.2.4
GLib 2.40.0

Not familiar with C programming , so not sure if i give you enough information.

[md2k]

This issue is very similar to http://www.midnight-commander.org/ticket/3121, only one exception - i have already patched version of MC, and i still have same problem on MacOS (Linux not tested yet)
And some time prompt passed as expected , some time not, and under debugger i unable reproduce this issue.

[md2k]

after looking to subshell.c functionality , i found that trick below solves my problem:
Looks like 500usec delay enough to solve some kind of race condition during read_subshell_prompt

--- subshell.c_curr 2015-04-09 15:49:07.000000000 +0200
+++ subshell.c  2015-04-10 16:37:28.000000000 +0200
@@ -969,7 +969,7 @@
 {
     int rc = 0;
     ssize_t bytes = 0;
-    struct timeval timeleft = { 0, 0 };
+    struct timeval timeleft = { 0, 500 };
     GString *p;
     gboolean prompt_was_reset = FALSE;

if set less then 500 usec, but not so often as with no any delay.
It will be great if this issue will be fixed in proper way, because i not the good person for C programming :)

[md2k]

one more detail: tested under linux and found that MC 4.8.5 do not have this issue , but higher versions have same issue on Linux / Mac (tested 4.8.11 , 4.8.12 ,13 ,14)
But not had time yet to do diff changes between versions.

[mmalchuk]

Confirm issue still exists under MacOSX 10.11.3
ZSH 5.2
ZSH_THEME="agnoster"

GNU Midnight Commander 4.8.15
Built with GLib 2.46.2
Using the S-Lang library with terminfo database
With builtin Editor
With subshell support as default
With support for background operations
With mouse support on xterm
With internationalization support
With multiple codepages support
Virtual File Systems: cpiofs, tarfs, sfs, extfs, ftpfs, sftpfs, fish
Data types: char: 8; int: 32; long: 64; void *: 64; size_t: 64; off_t: 64;

[md2k]

MC frozen seems, no further development will done, so if you want fix issue for yourself you just can apply patch and compile MC :)

--- subshell.c.orig 2014-04-01 12:54:01.000000000 +0200
+++ subshell.c  2015-04-10 21:21:41.000000000 +0200
@@ -759,7 +759,7 @@
 {
     /* This must be remembered across calls to init_subshell() */
     static char pty_name[BUF_SMALL];
-    char precmd[BUF_SMALL];
+    char precmd[BUF_MEDIUM];

     switch (check_sid ())
     {
@@ -874,7 +874,7 @@
     {
     case BASH:
         g_snprintf (precmd, sizeof (precmd),
-                    " PROMPT_COMMAND='pwd>&%d;kill -STOP $$'\n", subshell_pipe[WRITE]);
+           " PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND; }'pwd>&%d;kill -STOP $$'\n", subshell_pipe[WRITE]);
         break;

     case ZSH:
@@ -970,7 +970,7 @@
 {
     int rc = 0;
     ssize_t bytes = 0;
-    struct timeval timeleft = { 0, 0 };
+    struct timeval timeleft = { 0, 500 };
     GString *p;
     gboolean prompt_was_reset = FALSE;

Only check first destination file, i not remember against which version i did this patch.
dirty hack, but at least it work for me

[mmalchuk]

dirty indeed... shell code "kill -STOP" inside C ? :)

[md2k]

not inside it is passed to shell, so here is all ok :), but + struct timeval timeleft = { 0, 500 }; is really dirty hack

[md2k]

Bump....
i can see that issue with ZSH prompt still exists even with latest 4.17 builds.
@aborodin , can you fix this problem with prompt for ZSH ?
Please :)