Date: Sun, 24 Apr 2022 11:19:34 -0700
From: Noah Misch <noah@leadboat.com>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Robert Haas <robertmhaas@gmail.com>,
	Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pgsql: Allow db.schema.table patterns, but complain about random
 garbag
Message-ID: <20220424181934.GA1326154@rfd.leadboat.com>
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On Sun, Apr 24, 2022 at 01:09:08PM -0400, Andrew Dunstan wrote:
> On 2022-04-22 Fr 22:59, Noah Misch wrote:
> > The MinGW gcc crt*.o files do shell-glob expansion on the arguments before
> > entering main().  See https://google.com/search?q=mingw+command+line+glob for
> > various discussion of that behavior.  I suspect you experienced that, not any
> > IPC::Run behavior.  (I haven't tested, though.)  Commit 11e9caf likely had the
> > same cause, though the commit message attributed it to the msys shell rather
> > than to crt*.o.
> >
> > Let's disable that MinGW compiler behavior.
> > https://willus.com/mingw/_globbing.shtml lists two ways of achieving that.
> 
> Yeah. I can definitely confirm that this is the proximate cause of the
> issue, and not either IPC::Run or the shell, which is why all my
> experiments on this failed. With this patch

Thanks for confirming.

> diff --git a/src/include/port/win32.h b/src/include/port/win32.h
> index c6213c77c3..456c3f31f1 100644
> --- a/src/include/port/win32.h
> +++ b/src/include/port/win32.h
> @@ -77,3 +77,7 @@ struct sockaddr_un
>         char            sun_path[108];
>  };
>  #define HAVE_STRUCT_SOCKADDR_UN 1
> +
> +#ifndef _MSC_VER
> +extern int _CRT_glob = 0; /* 0 turns off globbing; 1 turns it on */
> +#endif
> 
> 
> fairywren happily passes the tests that Robert has since reverted.
> 
> 
> I'm rather tempted to call this CRT behaviour a mis-feature, especially
> as a default. I think we should certainly disable it in the development
> branch, and consider back-patching it, although it is a slight change in
> behaviour, albeit one that we didn't know about much less want or
> document. Still, we been building with mingw compilers for about 20
> years and haven't hit this before so far as we know, so maybe not.

I'd lean toward back-patching.  We position MSVC and MinGW as two ways to
build roughly the same PostgreSQL, not as two routes to different user-facing
behavior.  Since the postgresql.org/download binaries use MSVC, aligning with
their behavior is good.  It's fair to mention in the release notes, of course.

Does your win32.h patch build without warnings or errors?  Even if MinGW has
some magic to make that work, I suspect we'll want a non-header home.  Perhaps
src/common/exec.c?  It's best to keep this symbol out of libpq and other
DLLs, though I bet exports.txt would avoid functional problems.