[Scons-dev] Documentation

[Andrew C. Morrow]

A related issue is that it doesn't appear to be possible to completely
re-describe what it means to compute the 'signature' for a node. While you
can override 'contents', that seems dangerous, but overriding
get_content_hash seems insufficient, as there are several direct calls to
like SCons.Util.MD5signature(contents) in the SCons sources. Perhaps all of
those are, in practice, just passing the results of get_contents(), but
then why should get_content_hash exist?

I think this is another area that could use improvement, as it seems very
useful to be able to define for a node what its signature should be.

On Tue, Apr 18, 2017 at 9:28 AM, Jason Kenny <dragon512 at live.com> wrote:

> I would add that Parts we have a SymlinkFileNode that we added. It
> requires some magic as we have to deal with the “restricted” transmogrify
> between node in a safe way. It is non-trial to add a new node type. I
> believe the original design was to make this easier, with the notion that
> the FS object could be the local file system, or a FTP system, etc. I would
> love to see this part cleaned up and grown as I think it would be very
> powerful, however this need some careful development and thought to do
> correctly. I should add that I believe the non-trival part is bound more to
> the deisgn file based nodes, not other type of nodes as Value or Alias. I
> would like to see a more global node manager for all nodes, not just the
> one for the FS object that deals with file based nodes. Being able to look
> up a node in general is very useful
>
>
>
> Jason
>
>
>
> *From:* Scons-dev [mailto:scons-dev-bounces at scons.org] *On Behalf Of *Andrew
> C. Morrow
> *Sent:* Tuesday, April 18, 2017 7:43 AM
> *To:* SCons developer list <scons-dev at scons.org>
> *Subject:* Re: [Scons-dev] Documentation
>
>
>
>
>
> As a word of caution, we did something similar in the MongoDB tree for a
> new kind of "library":
>
>
>
> https://github.com/mongodb/mongo/blob/master/site_scons/
> site_tools/thin_archive.py#L53-L55
>
>
>
> However, it doesn't fully work, because the SCons internals expect to be
> able to transmogrify Nodes between the Entry, File, and Dir subclasses at
> will and without consideration as to any further sub-classing.
>
>
>
> The result, in our experience, lead to very cryptic errors (see
> https://jira.mongodb.org/browse/SERVER-27380), so we have disabled this
> tool until we figure out how to do this right.
>
>
>
> Andrew
>
>
>
>
>
>
>
> On Tue, Apr 18, 2017 at 4:26 AM, Russel Winder <russel at winder.org.uk>
> wrote:
>
> On Mon, 2017-04-17 at 08:24 -0700, Bill Deegan wrote:
> > Can you share your work in progress on bitbucket?
>
> The experimental repository is at https://github.com/russel/SCons_D_Exp
> eriment
> Even though SCons is a Mercurial world, the D world is a Git/GitHub
> one. Given that Atlassian have turned BitBucket into a Git place to
> compete with GitHub, I could push it to BitBucket as well, but I am not
> sure the dilution would achieve anything.
>
> > On Mon, Apr 17, 2017 at 2:06 AM, Russel Winder <russel at winder.org.uk>
> > wrote:
> >
> > > On Sun, 2017-04-16 at 11:19 -0700, Bill Deegan wrote:
> > > > Not sure what you mean.. Can you explain?
> > >
> > > For the dub tool, I believe I need a target node that is not a
> > > SCons.Node.FS.File nor a SCons.Node.FS.Dir, but the builder
> > > infrastructure is demanding that this be the case. I thus wanted to
> > > create a _Library class that was a sub-class of SCons.Node.FS.File
> > > but
> > > with all the rest of the information carried as well. (I may be
> > > going
> > > up totally the wrong tree, but this is learning by hacking, seeking
> > > feedback.) So I was looking for documentation to find out how to
> > > call
> > > the superclass initialiser, i.e. SCons.Node.FS.File.__init__.
>
> In the end I created a Subclass of SCons.Node.FS.File focussing on
> representing the library archive created, but carrying lots of other
> knowledge. I eventually settled on calling the superclass constructor
> at the end of the subclass constructor (don't you just love Python :-)
> thus:
>
> SCons.Node.FS.File.__init__(self, name, env.Dir(location), self)
>
> but I am really not sure that last argument is right. It works but it
> doesn't feel right. However there is no documentation on the fs
> parameter that I can find. I think maybe I am just not looking hard
> enough.
>
>
> --
> Russel.
> ============================================================
> =================
> Dr Russel Winder      t: +44 20 7585 2200   voip:
> sip:russel.winder at ekiga.net
> 41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel at winder.org.uk
> London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder
>
>
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