# HG changeset patch
# User Jun Wu <quark@fb.com>
# Date 1503989087 25200
# Node ID 72b5f4d53c58bc2a1750aaa330fe9e08f8142a57
# Parent  79ab5369d55a1151eebd2910e20941ad634d2892
revset: drop optimization about reordering "or" set elements

The reordering optimization is more important for "and" than "or", given the
implementation details about "addset" and "filteredset" - reordering "or"
may help "__contains__" test but not iteration, reordering "and" could help
both. We are going to simplify the tree to remove ordering information.
Removing "or" reordering optimization would make things simpler.

This effectively reverts c63cb2d10d6d. It tracks back to the "orset"
function added by the initial commit of revset (c9ce8ecd6).

In the future, we might consider optimization at runtime (ex. do reordering
and rewrites inside "orset").

Differential Revision: https://phab.mercurial-scm.org/D561

diff -r 79ab5369d55a -r 72b5f4d53c58 mercurial/revsetlang.py
--- a/mercurial/revsetlang.py	Tue Aug 29 17:51:54 2017 -0700
+++ b/mercurial/revsetlang.py	Mon Aug 28 23:44:47 2017 -0700
@@ -467,9 +467,6 @@
         flushss()
         if len(ts) == 1:
             return ws[0], ts[0] # 'or' operation is fully optimized out
-        if order != defineorder:
-            # reorder by weight only when f(a + b) == f(b + a)
-            ts = [wt[1] for wt in sorted(zip(ws, ts), key=lambda wt: wt[0])]
         return max(ws), (op, ('list',) + tuple(ts), order)
     elif op == 'not':
         # Optimize not public() to _notpublic() because we have a fast version
diff -r 79ab5369d55a -r 72b5f4d53c58 tests/test-revset.t
--- a/tests/test-revset.t	Tue Aug 29 17:51:54 2017 -0700
+++ b/tests/test-revset.t	Mon Aug 28 23:44:47 2017 -0700
@@ -2076,19 +2076,19 @@
       define)
     (or
       (list
-        ('symbol', '2')
         (range
           ('symbol', '0')
           ('symbol', '1')
-          follow))
+          follow)
+        ('symbol', '2'))
       follow)
     define)
   * set:
   <filteredset
     <spanset- 0:3>,
     <addset
-      <baseset [2]>,
-      <spanset+ 0:2>>>
+      <spanset+ 0:2>,
+      <baseset [2]>>>
   2
   1
   0
@@ -2569,69 +2569,6 @@
   1
   0
 
- 'A + B' can be rewritten to 'B + A' by weight only when the order doesn't
- matter (e.g. 'X & (A + B)' can be 'X & (B + A)', but '(A + B) & X' can't):
-
-  $ try -p optimized '0:2 & (reverse(contains("a")) + 2)'
-  * optimized:
-  (and
-    (range
-      ('symbol', '0')
-      ('symbol', '2')
-      define)
-    (or
-      (list
-        ('symbol', '2')
-        (func
-          ('symbol', 'reverse')
-          (func
-            ('symbol', 'contains')
-            ('string', 'a')
-            define)
-          follow))
-      follow)
-    define)
-  * set:
-  <filteredset
-    <spanset+ 0:3>,
-    <addset
-      <baseset [2]>,
-      <filteredset
-        <fullreposet+ 0:10>,
-        <contains 'a'>>>>
-  0
-  1
-  2
-
-  $ try -p optimized '(reverse(contains("a")) + 2) & 0:2'
-  * optimized:
-  (and
-    (range
-      ('symbol', '0')
-      ('symbol', '2')
-      follow)
-    (or
-      (list
-        (func
-          ('symbol', 'reverse')
-          (func
-            ('symbol', 'contains')
-            ('string', 'a')
-            define)
-          define)
-        ('symbol', '2'))
-      define)
-    define)
-  * set:
-  <addset
-    <filteredset
-      <spanset- 0:3>,
-      <contains 'a'>>,
-    <baseset [2]>>
-  1
-  0
-  2
-
 test sort revset
 --------------------------------------------