Do not lose constriction when teleporting.

Add a flag (default true) to actor::move_to_pos(), actor::moveto(), and
move_player_to_grid() indication whether clear_far_constrictions()
should be called.  When teleporting or blinking, pass false as that
flag, pull along constrictors/constrictees, and only then call
clear_far_constrictions().

Eronarn points out that it would be better to use an enum for the type
of motion, rather than the (now two) boolean flags.  I agree, but this
is a much bigger change so I have not done so yet.

It is still possible to get "comes along for the ride x2" if the
teleporter is contricting and constricted by the same actor.

1 files changed, 4 insertions, 1 deletions

diff --git a/crawl-ref/source/teleport.cc b/crawl-ref/source/teleport.cc
index 83b289efa1..12da6f094f 100644
--- a/crawl-ref/source/teleport.cc
+++ b/crawl-ref/source/teleport.cc
@@ -66,7 +66,7 @@ bool monster::blink_to(const coord_def& dest, bool quiet)
         seen_context = SC_TELEPORT_IN;
 
     const coord_def oldplace = pos();
-    if (!move_to_pos(dest))
+    if (!move_to_pos(dest, true, false))
         return (false);
 
     // handle constriction, if any
@@ -83,6 +83,9 @@ bool monster::blink_to(const coord_def& dest, bool quiet)
         else if (constricting[i] != NON_ENTITY)
             monster_teleport_to_player(constricting[i], dest);
 
+    // Now break our nonadjacent constrictions.
+    clear_far_constrictions();
+
     // Leave a purple cloud.
     if (!jump)
         place_cloud(CLOUD_TLOC_ENERGY, oldplace, 1 + random2(3), this);