[PATCH 1 of 6 V3] revset: teach optimize if current expression should define/follow order
Yuya Nishihara
yuya at tcha.org
Fri Jun 17 14:45:27 UTC 2016
# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1455627736 -32400
# Tue Feb 16 22:02:16 2016 +0900
# Node ID defa6a51c4613a4294db3a16a3dea7b5cb6025a0
# Parent d269e7db2f55f812c9ee1efe5626602614174df3
revset: teach optimize if current expression should define/follow order
New flag 'order' will be used to fix a couple of ordering bugs, such as:
a) 'x & (y | z)' disregards the order of 'x' (issue 5100)
b) 'x & y:z' is listed from 'y' to 'z'
c) 'x & y' can be rewritten as 'y & x' if weight(x) > weight(y)
(c) is a hidden bug of optimize(), which could be exposed if we've fixed
(a) and (b) in a different way. (a) and (b) are not bugs of optimize(), but
they can be addressed well in optimize() since optimize() knows the context.
'order' is tri-state. It starts with 'define', and shifts to 'follow' by
'x & y'. It changes back to 'define' on function call 'f(x)' or function-like
operation 'x (f) y' because 'f' may have its own ordering requirement for 'x'
and 'y'. The state 'any' will allow us to avoid extra cost that would be
necessary to constrain ordering where it isn't important, 'not x'. For details,
see also the tests added by the next patch.
diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -2302,6 +2302,46 @@ methods = {
"parentpost": p1,
}
+# Constants for ordering requirement, used in _optimize():
+#
+# If 'define', any future functions and operations can change the ordering of
+# the entries in the set. If 'follow', any future functions and operations
+# should take the ordering specified by the first operand to the '&' operator.
+#
+# For instance,
+#
+# X & (Y | Z)
+# ^ ^^^^^^^
+# | follow
+# define
+#
+# will be evaluated as 'or(y(x()), z(x()))', where 'x()' can change the order
+# of the entries in the set, but 'y()', 'z()' and 'or()' shouldn't.
+#
+# 'any' means the order doesn't matter. For 'not X', 'x()' may change the
+# order of the entries in the initial set. So for 'not (x | y)', we don't
+# have to fix the result of 'or()' to enforce the ordering requirement.
+# Also, 'not sort(x)' can be optimized to 'not x'.
+#
+# Transition of ordering requirement:
+#
+# 1. starts with 'define'
+# 2. shifts to 'follow' by 'x & y'
+# 3. changes back to 'define' on function call 'f(x)' or function-like
+# operation 'x (f) y' because 'f' may have its own ordering requirement
+# for 'x' and 'y' (e.g. 'first(x)')
+#
+_anyorder = 'any' # don't care the order
+_defineorder = 'define' # should define the order
+_followorder = 'follow' # must follow the current order
+
+# transition table for 'x & y', from the current expression 'x' to 'y'
+_tofolloworder = {
+ _anyorder: _anyorder,
+ _defineorder: _followorder,
+ _followorder: _followorder,
+}
+
def _matchonly(revs, bases):
"""
>>> f = lambda *args: _matchonly(*map(parse, args))
@@ -2317,7 +2357,11 @@ def _matchonly(revs, bases):
and getstring(bases[1][1], _('not a symbol')) == 'ancestors'):
return ('list', revs[2], bases[1][2])
-def _optimize(x, small):
+def _optimize(x, small, order):
+ """
+ 'order' specifies how the current expression 'x' is ordered (see the
+ constants defined above)
+ """
if x is None:
return 0, x
@@ -2327,30 +2371,32 @@ def _optimize(x, small):
op = x[0]
if op == 'minus':
- return _optimize(('and', x[1], ('not', x[2])), small)
+ return _optimize(('and', x[1], ('not', x[2])), small, order)
elif op == 'only':
t = ('func', ('symbol', 'only'), ('list', x[1], x[2]))
- return _optimize(t, small)
+ return _optimize(t, small, order)
elif op == 'onlypost':
- return _optimize(('func', ('symbol', 'only'), x[1]), small)
+ return _optimize(('func', ('symbol', 'only'), x[1]), small, order)
elif op == 'dagrangepre':
- return _optimize(('func', ('symbol', 'ancestors'), x[1]), small)
+ return _optimize(('func', ('symbol', 'ancestors'), x[1]), small, order)
elif op == 'dagrangepost':
- return _optimize(('func', ('symbol', 'descendants'), x[1]), small)
+ t = ('func', ('symbol', 'descendants'), x[1])
+ return _optimize(t, small, order)
elif op == 'rangeall':
- return _optimize(('range', ('string', '0'), ('string', 'tip')), small)
+ t = ('range', ('string', '0'), ('string', 'tip'))
+ return _optimize(t, small, order)
elif op == 'rangepre':
- return _optimize(('range', ('string', '0'), x[1]), small)
+ return _optimize(('range', ('string', '0'), x[1]), small, order)
elif op == 'rangepost':
- return _optimize(('range', x[1], ('string', 'tip')), small)
+ return _optimize(('range', x[1], ('string', 'tip')), small, order)
elif op == 'negate':
s = getstring(x[1], _("can't negate that"))
- return _optimize(('string', '-' + s), small)
+ return _optimize(('string', '-' + s), small, order)
elif op in 'string symbol negate':
return smallbonus, x # single revisions are small
elif op == 'and':
- wa, ta = _optimize(x[1], True)
- wb, tb = _optimize(x[2], True)
+ wa, ta = _optimize(x[1], True, order)
+ wb, tb = _optimize(x[2], True, _tofolloworder[order])
w = min(wa, wb)
# (::x and not ::y)/(not ::y and ::x) have a fast path
@@ -2376,12 +2422,12 @@ def _optimize(x, small):
else:
s = '\0'.join(t[1] for w, t in ss)
y = ('func', ('symbol', '_list'), ('string', s))
- w, t = _optimize(y, False)
+ w, t = _optimize(y, False, order)
ws.append(w)
ts.append(t)
del ss[:]
for y in x[1:]:
- w, t = _optimize(y, False)
+ w, t = _optimize(y, False, order)
if t is not None and (t[0] == 'string' or t[0] == 'symbol'):
ss.append((w, t))
continue
@@ -2399,34 +2445,34 @@ def _optimize(x, small):
# Optimize not public() to _notpublic() because we have a fast version
if x[1] == ('func', ('symbol', 'public'), None):
newsym = ('func', ('symbol', '_notpublic'), None)
- o = _optimize(newsym, not small)
+ o = _optimize(newsym, not small, order)
return o[0], o[1]
else:
- o = _optimize(x[1], not small)
+ o = _optimize(x[1], not small, _anyorder)
return o[0], (op, o[1])
elif op == 'parentpost':
- o = _optimize(x[1], small)
+ o = _optimize(x[1], small, _defineorder)
return o[0], (op, o[1])
elif op == 'group':
- return _optimize(x[1], small)
+ return _optimize(x[1], small, order)
elif op in 'dagrange range parent ancestorspec':
if op == 'parent':
# x^:y means (x^) : y, not x ^ (:y)
post = ('parentpost', x[1])
if x[2][0] == 'dagrangepre':
- return _optimize(('dagrange', post, x[2][1]), small)
+ return _optimize(('dagrange', post, x[2][1]), small, order)
elif x[2][0] == 'rangepre':
- return _optimize(('range', post, x[2][1]), small)
-
- wa, ta = _optimize(x[1], small)
- wb, tb = _optimize(x[2], small)
+ return _optimize(('range', post, x[2][1]), small, order)
+
+ wa, ta = _optimize(x[1], small, _defineorder)
+ wb, tb = _optimize(x[2], small, _defineorder)
return wa + wb, (op, ta, tb)
elif op == 'list':
- ws, ts = zip(*(_optimize(y, small) for y in x[1:]))
+ ws, ts = zip(*(_optimize(y, small, order) for y in x[1:]))
return sum(ws), (op,) + ts
elif op == 'func':
f = getstring(x[1], _("not a symbol"))
- wa, ta = _optimize(x[2], small)
+ wa, ta = _optimize(x[2], small, _defineorder)
if f in ("author branch closed date desc file grep keyword "
"outgoing user"):
w = 10 # slow
@@ -2446,7 +2492,7 @@ def _optimize(x, small):
return 1, x
def optimize(tree):
- _weight, newtree = _optimize(tree, small=True)
+ _weight, newtree = _optimize(tree, small=True, order=_defineorder)
return newtree
# the set of valid characters for the initial letter of symbols in
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