[Python-Dev] "Absolute" paths in PEP 376 RECORD files

[P.J. Eby]

At 03:31 PM 7/10/2009 +0200, Tarek Ziadé wrote:
>On Thu, Jul 9, 2009 at 9:09 PM, P.J. Eby<pje at telecommunity.com> wrote:
> > At 02:46 PM 7/9/2009 -0400, Tres Seaver wrote:
> >>
> >> -----BEGIN PGP SIGNED MESSAGE-----
> >> Hash: SHA1
> >>
> >> Nick Coghlan wrote:
> >> > P.J. Eby wrote:
> >> >>>  Also,
> >> >>> why should the RECORD file be generated at all by bdist* commands?
> >> >> bdist commands that use "install --root" will get it as a side effect,
> >> >> so they don't have to do anything special.  They needn't even generate
> >> >> the PREFIXES, if PREFIXES is also generated by "install --root", and
> >> >> omits the root from the prefixes written.  In other words, most bdist
> >> >> tools wouldn't change.  bdist_wininst and bdist_msi might need to
> >> >> regenerate PREFIXES at actual installation time, but AFAIK those are
> >> >> the
> >> >> only ones.  (And the spec would allow for the possibility that a
> >> >> PREFIXES file can be incorrect.)
> >> >
> >> > I haven't seen any suggestions for handling non-relative paths that are
> >> > cleaner than this. The distutils based list that Tarek posted also gives
> >> > a good "starter set" of supported entries in the PREFIXES file:
> >> >
> >> > PURELIB=<path>
> >> > PLATLIB=<path>
> >> > HEADERS=<path>
> >> > SCRIPTS=<path>
> >> > DATA=<path>
> >> >
> >> > The question then would be whether relative paths should be handled
> >> > directly in the RECORD file (as in the current PEP) or by writing a "."
> >> > into PREFIXES to indicate relative paths.
>
>I like the idea of a separated PREFIXES file, then using variables in
>the RECORD file.

Please note that my proposal intentionally omitted "variables", but 
instead used a separate column to designate the prefix.  This allows 
some guarantees regarding path sanity that could otherwise be abused, 
like combining prefixes or inserting them in the middle of paths.  In 
this way, the formal conversion of a path would be 
os.path.join(PREFIX, *relative_path.split('/')), rather than a 
variable expansion.