[PATCH] progress: skip progress estimate when current exceeds total

[timeless]

# HG changeset patch
# User timeless <timeless at gmail.com>
# Date 1300013265 -7200
# Node ID 40db5a0ba4c811644dd97ce4a1dbd2b0d85172df
# Parent  0652b2da832daada866a68f7a4359227570c2447
progress: skip progress estimate when current exceeds total

This is to avoid nonsensical output like:

bundling [  <=>                          ] 463/405 -4s

diff --git a/hgext/progress.py b/hgext/progress.py
--- a/hgext/progress.py
+++ b/hgext/progress.py
@@ -207,13 +207,26 @@ class progbar(object):
         if total is None:
             return ''
         initialpos = self.startvals[topic]
-        target = total - initialpos
-        delta = pos - initialpos
-        if delta > 0:
+        displacement = pos - initialpos + 1
+        remaining = total - pos
+        # 0  i       p      t p
+        #     \--d--/ \--r--/
+        #     (  e  ) (  s  )
+        # i = initialpos
+        # d = displacement from i to p
+        # p = pos (note that pos need not be <= total)
+        # r = remaining from pos to total
+        # e = elapsed
+        # s = seconds to reach t
+        #
+        # the time it takes to reach total
+        # assuming a constant rate (displacement/time)
+        # should be roughly t1 = (t * r) / d
+        if remaining >= 0:
             elapsed = now - self.starttimes[topic]
             if elapsed > float(
                 self.ui.config('progress', 'estimate', default=2)):
-                seconds = (elapsed * (target - delta)) // delta + 1
+                seconds = (elapsed * (remaining)) // displacement
                 return fmtremaining(seconds)
         return ''
 
diff --git a/tests/test-progress.t b/tests/test-progress.t
--- a/tests/test-progress.t
+++ b/tests/test-progress.t
@@ -158,6 +158,15 @@ test delay time estimates
   loop [=============================>           ] 3/4 23w02d
                                                               \r (esc)
 
+Time estimate with count overrun:
+  $ hg -y loop --total 4 6 2>&1 | python $TESTDIR/filtercr.py
+  
+  loop [=====================>                      ] 2/4 23s
+  loop [================================>           ] 3/4 12s
+  loop [===========================================>] 4/4 01s
+  loop [ <=>                                            ] 5/4
+                                                              \r (esc)
+
 Time estimates should not fail when there's no end point:
   $ hg -y loop -- -4 2>&1 | python $TESTDIR/filtercr.py