DESCRIPTION

    This patch adds an invulnerability cheat to Battle for Wesnoth
    1.2.8. With this patch, the wesnoth binary honours the following
    environment variables :

        DEATHLESS_SIDES=num[,num]...

            Value is interpreted as a list of side numbers separated by
            white space or commas.  All units on any of specified sides
            are unkillable.

        DEATHLESS_TEAM=str

            Value is interpreted as a team name. All units on the
            specified team are unkillable.

    "Unkillable" means that the hit points of the unit never drop below 1,
    no matter how much damage it takes.

EXAMPLE

    Start the game with units from teams "One", 2 and 4 unkillable :

        DEATHLESS_SIDES=2,4 DEATHLESS_TEAM=One ./wesnoth

NOTES

    The team names for DEATHLESS_TEAM can be difficult to infer. The
    matching is case-sensitive and the names shown in the in-game stats
    table sometimes have a different case than the internal variables
    against which the value of DEATHLESS_TEAM is compared.

    When playing against the computer, DEATHLESS_SIDES=1 is a good first
    guess.

    Dwarvish Ulfserkers make wonderful recruits with this cheat. Because
    they have the "berserk" weapon special, they are practically
    guaranteed to end the turn with at least one empty hex around them.
    Thus, a pair of DU working together is unstoppable : on odd turns,
    DU #1 cleans the hex in front of DU #2 so DU #2 can advance and
    vice-versa on even turns.

    Unkillable units make enemy magnets. Because they look like easy
    prey (hit points stuck at 1), the AI tends to keep sending units
    against them, neglecting other concerns such as securing more
    villages.

 -- AYM 2008-01-20


diff -ur wesnoth-1.2.8/src/unit.cpp wesnoth-1.2.8-aym1/src/unit.cpp
--- wesnoth-1.2.8/src/unit.cpp	2007-02-23 18:17:44.000000000 +0100
+++ wesnoth-1.2.8-aym1/src/unit.cpp	2008-01-04 16:37:13.000000000 +0100
@@ -786,9 +786,97 @@
 	}
 }
 
+/* AYM 2007-12-29 */
+#include <errno.h>
+
+static const char	deathless_sides_name[]	= "DEATHLESS_SIDES";
+static const char	deathless_team_name[]	= "DEATHLESS_TEAM";
+
+static long		 deathless_sides_bitmap	= 1 << 31;
+static const char	*deathless_team_inval	= "";
+static const char	*deathless_team		= deathless_team_inval;
+
+static void get_cheats ()
+{
+
+  /* Parse $DEATHLESS_SIDES */
+  if (deathless_sides_bitmap == 1 << 31)
+  {
+    const char *s = getenv (deathless_sides_name);
+    deathless_sides_bitmap = 0;
+    if (s == NULL)
+    {
+      fprintf (stderr, "%s not set\n", deathless_sides_name);
+    }
+    else
+    {
+      fprintf (stderr, "%s set to \"%s\"\n", deathless_sides_name, s);
+      for (const char *p = s; *p != '\0';)
+      {
+	char *p2;
+	errno = 0;
+	long n = strtol (p, &p2, 0);
+	if (errno != 0)
+	{
+	  fprintf (stderr, "%s(%d): %s\n", deathless_sides_name, int (p - s), strerror (errno));
+	  break;
+	}
+	fprintf (stderr, "%s(%d): parsed \"%.*s\" as %ld\n", deathless_sides_name, int (p - s), int (p2 - p), p, n);
+	if (n < 1)
+	  fprintf (stderr, "%s(%d): side# < 1 (%ld)\n", deathless_sides_name, int (p - s), n);
+	else if (n >= 31)
+	  fprintf (stderr, "%s(%d): side# >= 31 (%ld)\n", deathless_sides_name, int (p - s), n);
+	else
+	  deathless_sides_bitmap |= (1 << n);
+	p = p2;
+	while (*p == ',' || isspace (*p))
+	  p++;
+      }
+      fprintf (stderr, "%s: %#lx\n", deathless_sides_name, deathless_sides_bitmap);
+    }
+  }
+
+  if (deathless_team == deathless_team_inval)
+  {
+    deathless_team = getenv (deathless_team_name);
+    if (deathless_team == NULL)
+      fprintf (stderr, "%s not set\n", deathless_team_name);
+    else
+      fprintf (stderr, "%s set to \"%s\"\n", deathless_team_name, deathless_team);
+  }
+}
+
 bool unit::take_hit(int damage)
 {
+	get_cheats ();
+	fprintf (stderr,
+	  "take_hit: name \"%s\", desc \"%s\", cu_ \"%s\","
+	    " side %u, team_name \"%s\", user_ \"%s\"\n"
+	  , name_.c_str ()
+	  , description_.c_str ()
+	  , custom_unit_description_.c_str ()
+	  , side ()
+	  , (*teams_)[side_ - 1].team_name ().c_str ()
+	  , (*teams_)[side_ - 1].user_team_name ().c_str ()
+	);
 	hit_points_ -= damage;
+	if (hit_points_ < 1)
+	{
+		const char *reason = NULL;
+		if (side_ < 31 && (deathless_sides_bitmap & (1 << side_)))
+			reason = deathless_sides_name;
+		else if (deathless_team != NULL
+			 && ( strcmp (deathless_team, custom_unit_description_.c_str ()) == 0
+			   || strcmp (deathless_team, (*teams_)[side_ - 1].team_name ().c_str ()) == 0
+			   || strcmp (deathless_team, (*teams_)[side_ - 1].user_team_name ().c_str ()) == 0))
+			reason = deathless_team_name;
+		if (reason != NULL)
+		{
+			fprintf (stderr, "%s would have died (%d), saved because of %s\n",
+				custom_unit_description_.c_str (), hit_points_, reason);
+			hit_points_ = 1;
+		}
+	}
 	return hit_points_ <= 0;
 }
 void unit::heal(int amount)