On 6/7/2010 4:16 PM, James M. Lawrence wrote:
Yes, my original fix was to replace EARLY with an analogous LATE
object in FileTask#timestamp. Although it worked, I was hesitant to
make a seemingly fundamental change (in the opposite direction, no
less). But it's possible that EARLY has been harmlessly wrong for six
years.
There are only two significant places where FileTask#timestamp is used
(that I found) where changing EARLY to LATE would make a difference. One
is FileTask#out_of_date? which is only called from FileTask#needed?; and
when needed? is called where it really counts, the prerequisites have
all been invoked, so the file-not-found condition should not hit.
The other place is the base Task#timestamp; which propagates the newest
timestamp of its prereqs, or Time.now if there are no prereqs. The
ramifications of that timestamp coming back 'LATE' aren't clear to me.
Nor is it clear to me why it propagates its prereqs' timestamps as its
own. We could always modify that method to substitute EARLY for LATE to
preserve the original behavior, which is what I've done.
Do you have this running on a large project, and does it appear to
work correctly? My change removes the old workaround, so you should
get latest with "gem install drake" or from github (though you'll have
to add the "if needed?" clause yourself, for the moment).
Yes, it has been running on a large project without issue (since not
long after I posted the patch to the bug report); and much more
recently, I have implemented the LATE change to FileTask#timestamp.
Here's what I've got:
module Rake
class Task
def timestamp
@prerequisites.collect { |p|
t = application[p].timestamp
t == Rake::LATE ?Rake::EARLY :t
}.max || Time.now
end
end
class FileTask < Task
def needed?
t = timestamp
t == Rake::LATE || out_of_date?(t)
end
def timestamp
begin
File.mtime(name)
rescue Errno::ENOENT
Rake::LATE
end
end
end
end
Note, this also contains a couple of additional optimizations I added to
FileTask's methods to reduce the number of stat syscalls. (With the
original code, each call to needed? generated 2n+3 stat calls where n is
the number of file prereqs. This code generates n+1 stat calls.)
I just grabbed drake-0.8.7.0.2.4 and I'll hammer on it and report back
in a couple days.
-heath
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