* lisp/emacs-lisp/avl-tree.el (avl-tree--enter-balance): Fix paren typo.

(avl-tree--check, avl-tree--check-node): New funs.

Fixes: debbugs:11077

2 files changed, 22 insertions, 7 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 7d81bbb46b5..65018db7e4d 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,8 +1,14 @@
+2012-03-27  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * emacs-lisp/avl-tree.el (avl-tree--enter-balance): Fix paren typo
+        (bug#11077).
+        (avl-tree--check, avl-tree--check-node): New funs.
+
 2012-03-27  Martin Rudalics  <rudalics@gmx.at>
 
         * window.el (switch-to-visible-buffer): New option.
-        (switch-to-prev-buffer, switch-to-next-buffer): Observe
-        switch-to-visible-buffer.  Make sure that checking for a window
+        (switch-to-prev-buffer, switch-to-next-buffer):
+        Observe switch-to-visible-buffer.  Make sure that checking for a window
         showing a buffer already is done on the same frame.
 
 2012-03-27  Glenn Morris  <rgm@gnu.org>
@@ -28,8 +34,7 @@
 2012-03-25  Eli Zaretskii  <eliz@gnu.org>
 
         * makefile.w32-in (install): Use $(DIRNAME)_same-dir.tst instead
-        of same-dir.tst, to avoid stepping on other (parallel) Make job's
-        toes.
+        of same-dir.tst, to avoid stepping on other (parallel) Make job's toes.
 
 2012-03-25  Chong Yidong  <cyd@gnu.org>
 
diff --git a/lisp/emacs-lisp/avl-tree.el b/lisp/emacs-lisp/avl-tree.el
index cb5ea048999..9f348767478 100644
--- a/lisp/emacs-lisp/avl-tree.el
+++ b/lisp/emacs-lisp/avl-tree.el
@@ -295,9 +295,9 @@ Return t if the height of the tree has grown."
                 (if (> (* sgn b2) 0) (- sgn) 0)
               (avl-tree--node-balance p1)
                 (if (< (* sgn b2) 0) sgn 0)
-              (avl-tree--node-branch node branch) p2
-              (avl-tree--node-balance
-               (avl-tree--node-branch node branch)) 0))
+                (avl-tree--node-branch node branch) p2))
+      (setf (avl-tree--node-balance
+             (avl-tree--node-branch node branch)) 0)
       nil))))
 
 (defun avl-tree--do-enter (cmpfun root branch data &optional updatefun)
@@ -339,6 +339,16 @@ inserted data."
         (cons nil newdata))  ; return value
       ))))
 
+(defun avl-tree--check (tree)
+  "Check the tree's balance."
+  (avl-tree--check-node (avl-tree--root tree)))
+(defun avl-tree--check-node (node)
+  (if (null node) 0
+    (let ((dl (avl-tree--check-node (avl-tree--node-left node)))
+          (dr (avl-tree--check-node (avl-tree--node-right node))))
+      (assert (= (- dr dl) (avl-tree--node-balance node)))
+      (1+ (max dl dr)))))
+
 ;; ----------------------------------------------------------------