Date: Sat, 16 Dec 2017 16:16:30 +0100
From: Christoph Berg <christoph.berg@credativ.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>,
	Michael Paquier <michael.paquier@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Reproducible builds: genbki.pl vs schemapg.h
Message-ID: <20171216151630.GA8824@msg.credativ.de>
Mail-Followup-To: Christoph Berg <christoph.berg@credativ.de>,
	Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>,
	Michael Paquier <michael.paquier@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>
References: <20171215102223.GB31812@msg.df7cb.de>
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 <20171215181337.GA6149@msg.credativ.de>
 <CAB7nPqQsxACj9KyrJjn48HebtK1MAAiQ30TRd47Xfgt4rhQYuQ@mail.gmail.com>
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Re: Tom Lane 2017-12-16 <5525.1513381145@sss.pgh.pa.us>
> >>> As per
> >>> https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/postgresql-10.html,
> >>> that's the only place that makes it into the resulting binary.
> 
> I'm fairly confused by this claim.  Since the string in question is in a
> comment, it really shouldn't affect built binaries at all.  I can believe
> that it would affect the non-binary contents of the finished package,

"Binary" in that context was the .deb package file (in contrast to the
.dsc source package).

> In my build, neither one of these files contains any path information;
> I speculate that you need to use a VPATH build to have an issue, or
> maybe Debian's build environment does something even weirder.

This is a VPATH build, yes.

> > It's not like $0 instead of a hardcoded name in the header actually buys
> > us anything afaict.
> 
> Agreed so far as the script name goes.  However, two out of three of these
> scripts also print their input file names, and I'm suspicious that that
> output is also gonna change in a VPATH build.  I'm a little less inclined
> to buy the claim that we're not losing anything if we suppress that :-(

Well, patching this instance of $0 would fix a binary-package
variation in practise. Of course there might be more issues waiting to
come into effect, but I don't see why that would be an argument
against fixing the current issue.

Christoph
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