# HG changeset patch
# User Yuya Nishihara <yuya@tcha.org>
# Date 1464782044 -32400
# Node ID 80c86b9bb40bee0c7ade9e67bb499d6679b71c5d
# Parent  3664537386aba92ee1b340e6c0428a61190dc73e
revset: forward ordering requirement to argument of present()

present() is special in that it returns the argument set with no
modification, so the ordering requirement should be forwarded.

We could make present() fix the order like orset(), but that would be silly
because we know the extra filtering cost is unnecessary.

diff -r 3664537386ab -r 80c86b9bb40b mercurial/revset.py
--- a/mercurial/revset.py	Wed Sep 14 11:39:47 2016 -0500
+++ b/mercurial/revset.py	Wed Jun 01 20:54:04 2016 +0900
@@ -2473,7 +2473,13 @@
     elif op == 'keyvalue':
         return (op, x[1], _analyze(x[2], order))
     elif op == 'func':
-        return (op, x[1], _analyze(x[2], defineorder), order)
+        f = getsymbol(x[1])
+        d = defineorder
+        if f == 'present':
+            # 'present(set)' is known to return the argument set with no
+            # modification, so forward the current order to its argument
+            d = order
+        return (op, x[1], _analyze(x[2], d), order)
     raise ValueError('invalid operator %r' % op)
 
 def analyze(x, order=defineorder):
diff -r 3664537386ab -r 80c86b9bb40b tests/test-revset.t
--- a/tests/test-revset.t	Wed Sep 14 11:39:47 2016 -0500
+++ b/tests/test-revset.t	Wed Jun 01 20:54:04 2016 +0900
@@ -1485,7 +1485,23 @@
       <baseset [0, 1]>>>
   2
 
- 'present()' should do nothing other than suppressing an error:
+ because 'present()' does nothing other than suppressing an error, the
+ ordering requirement should be forwarded to the nested expression
+
+  $ try -p optimized 'present(2 + 0 + 1)'
+  * optimized:
+  (func
+    ('symbol', 'present')
+    (func
+      ('symbol', '_list')
+      ('string', '2\x000\x001')
+      define)
+    define)
+  * set:
+  <baseset [2, 0, 1]>
+  2
+  0
+  1
 
   $ try --optimize '2:0 & present(0 + 1 + 2)'
   (and
@@ -1510,15 +1526,16 @@
       (func
         ('symbol', '_list')
         ('string', '0\x001\x002')
-        define)
+        follow)
       follow)
     define)
   * set:
-  <baseset [0, 1, 2]>
-  0
+  <filteredset
+    <spanset- 0:2>,
+    <baseset [0, 1, 2]>>
+  2
   1
-  2
- BROKEN: should be '2 1 0'
+  0
 
  'reverse()' should take effect only if it is the outermost expression: