Ticket #4521: really escape fish shell history.

Some of the "service" commands generated by the mc "leak" into the fish
subshell history available to the user. An example to reproduce:

  *  set user shell to fish and start mc (SHELL=/usr/bin/fish mc)
  *  navigate to any directory
  *  press Ctrl+o
  *  press \u2191 button (UP, go back in history)
  *  observe " cd (printf '%b' ... " command

This commit avoids the " cd (printf '%b' ... " commands in the fish
history.

Signed-off-by: Andrew Borodin <[email protected]>

src/subshell/common.c

@@ -1714,6 +1714,18 @@ do_subshell_chdir (const vfs_path_t * vpath, gboolean update_prompt)
                 return;
             }
     }
+
+    /* A quick and dirty fix for fish shell. For some reason, fish does not
+     * execute all the commands sent to it from Midnight Commander :(
+     * An example of such buggy behavior is presented in ticket #4521.
+     * TODO: Find the real cause and fix it "the right way" */
+    if (mc_global.shell->type == SHELL_FISH)
+    {
+        write_all (mc_global.tty.subshell_pty, "\n", 1);
+        subshell_state = RUNNING_COMMAND;
+        feed_subshell (QUIETLY, TRUE);
+    }
+
     /* The initial space keeps this out of the command history (in bash
        because we set "HISTCONTROL=ignorespace") */
     write_all (mc_global.tty.subshell_pty, " cd ", 4);
@@ -1778,12 +1790,16 @@ do_subshell_chdir (const vfs_path_t * vpath, gboolean update_prompt)
         }
     }
 
-    /* Really escape Zsh history */
-    if (mc_global.shell->type == SHELL_ZSH)
+    /* Really escape Zsh/Fish history */
+    if (mc_global.shell->type == SHELL_ZSH || mc_global.shell->type == SHELL_FISH)
     {
         /* Per Zsh documentation last command prefixed with space lingers in the internal history
          * until the next command is entered before it vanishes. To make it vanish right away,
-         * type a space and press return. */
+         * type a space and press return.
+         *
+         * Fish shell now also provides the same behavior:
+         * https://github.com/fish-shell/fish-shell/commit/9fdc4f903b8b421b18389a0f290d72cc88c128bb
+         * */
         write_all (mc_global.tty.subshell_pty, " \n", 2);
         subshell_state = RUNNING_COMMAND;
         feed_subshell (QUIETLY, TRUE);