Merge pull request #1132 from urbit/hotfix

Hotfix

app/talk.hoon

@@ -2098,7 +2098,7 @@
     ::  render circle (as glyph if we can).
     ?~  moy
       =+  cha=(~(get by bound) one ~ ~)
-      =-  ?~(cha - "{u.cha ~} {-}")
+      =-  ?~(cha - "{u.cha ~}")
       ~(cr-phat cr one)
     (~(cr-curt cr one) u.moy)
   --

sys/hoon.hoon

@@ -1875,9 +1875,10 @@
   ::
   ++  nap                                               ::  removes head
     ?>  ?=(^ a)
-    ?:  =(~ l.a)  r.a
-    =+  b=get(a l.a)
-    bal(a ^+(a [p.b q.b r.a]))
+    ?~  a  ~
+    =+  b=get
+    ?~  q.b  ~
+    bal(a ^+(a [n=n.q.b l=l.q.b r=r.q.b]))
   ::
   ++  put                                               ::  insert new tail
     |*  b/*

tests/sys/hoon/qeu.hoon

@@ -0,0 +1,51 @@
+::  test a fix for a bug in +nap:to affecting three-item queues.
+::
+::    (see  https://github.com/urbit/arvo/issues/1100 for details)
+::
+::    the test creates several queues from known lists and recursively
+::    unqueues the top, comparing it with the current element of the list.
+::
+/+  *test
+::
+=/  descending   ~[7 6 5 4 3 2 1]
+=/  ascending    ~[1 2 3 4 5 6 7]
+=/  unsorted     ~[1 6 3 5 7 2 4]
+=/  duplicates   ~[1 1 7 4 6 9 4]
+::
+=>
+|%
+++  unqueue
+  |=  [queue=(qeu @) test=(list @)]
+  ^-  tang
+  %-  zing
+  |-  ^-  (list tang)
+  ?~  test   ~
+  ?~  queue  ~
+  :_  $(queue ~(nap to queue), test t.test)
+  %+  expect-eq
+    !>  (need ~(top to queue))
+    !>  i.test
+--
+::
+|%
+::
+++  test-descending-sorted-list  ^-  tang
+  ::
+  =+  queue=(~(gas to `(qeu @)`~) descending)
+  (unqueue [queue descending])
+::
+++  test-ascending-sorted-list  ^-  tang
+  ::
+  =+  queue=(~(gas to `(qeu @)`~) ascending)
+  (unqueue [queue ascending])
+::
+++  test-unsorted-list  ^-  tang
+  ::
+  =+  queue=(~(gas to `(qeu @)`~) unsorted)
+  (unqueue [queue unsorted])
+::
+++  test-duplicates-list  ^-  tang
+  ::
+  =+  queue=(~(gas to `(qeu @)`~) duplicates)
+  (unqueue [queue duplicates])
+--