Re: [PATCH] implicit Unicode data tables generation

[Corinna Vinschen <vinschen at redhat dot com>]

On Mar 13 14:56, Thomas Wolff wrote:
> On 13.03.2018 11:46, Corinna Vinschen wrote:
> > On Mar 12 20:32, Thomas Wolff wrote:
> > > Am 12.03.2018 um 15:21 schrieb Corinna Vinschen:
> > > > A build dependency to unicode-ucd should not be required.  Why not have
> > > > automatic build rules which are simply skipped if the file doesn't
> > > > exist?  So somebody can download the file and the rules do the rest?
> > > > It's not *that* important, but a nice feature.
> > > The easiest way would be that the mkunidata scripts just ignore the missing
> > > files, like in the patch attached.
> > > On the other hand, in my original scripts I had the additional fallback
> > > option to download them from unicode.org on demand.
> > > If that's acceptable in a build process, I could add that back in.
> > > Or just drop those rules and stay explicit?
> > Implicit would be nice, it's not actually a hard requirement.
> > 
> > We must not rely on system-installed files outside the source tree,
> > build tree or outside the toolchain.
> That's why my patch yesterday would ignore missing of the files.
> 
> > Please provide a patch removing any ln to files under /usr/share, etc.
> Is dependency to one more cygwin package (like obscure ones like "cocom"
> already) a problem?
> Is "ln -s" the culprit, so would "cp" be OK?

The cocom requirement is in Cygwin, not in newlib.  Please keep in mind
that newlib is not dependent on Cygwin but vice versa.  The newlib build
shouldn't make assumptions we can get away with for Cygwin.

You can also never make assumptions about the age of a file provided by
your build OS.  There's a good chance the OS is providing an older
Unicode data file version than the one you actually want to build the
dependent files from.  Worst case, older than the currently supported
Unicode version.

The bottom line is, the Unicode data file has been either downloaded into
the expected location in libc/ctype, or it's not available.

> > The explicit rules add a rule to download the Unicode.txt file into the
> > src tree.  That's the only file we may rely on.  If it doesn't exist,
> > an implicit rule should not break the build.
> Well, my mentioned patch wouldn't break it anymore. I can tweak the script
> further to your preference, but if a solution would involve further Makefile
> changes (like "phony" usage), I would ask you to do that.

I have enough other stuff on my plate, so, no.


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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