Horton

Re: Is this a bug in pg_current_logfile() on Windows?

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Cc: Thomas Kellerer <shammat@gmx.net>, pgsql-hackers@lists.postgresql.org
Date: 2020-07-09T02:40:42Z
Lists: pgsql-hackers, pgsql-general 
I wrote:
> Andrew Dunstan <andrew.dunstan@2ndquadrant.com> writes:
>> Seems reasonable. If we rip it out completely we'll have to find all the
>> places it breaks and fix them. And we'll almost certainly get new
>> breakage. If it's hiding a real bug we'll have to do that, but I'd be
>> reluctant unless there's actual proof.

> Hard to tell.  What I propose to do right now is change the \r filters
> as shown above, and see if the test I added in 004_logrotate.pl starts
> to show failures on Windows.  If it does, and no other place does,
> I'm willing to be satisfied with that.  If we see *other* failures then
> that'd prove that the problem is real, no?

So I did that, and the first report is from bowerbird and it's still
green.  Unless I'm completely misinterpreting what's happening (always
a possibility), that means we're still managing to remove "data"
occurrences of \r.

The most likely theory about that, I think, is that IPC::Run::run already
translated any \r\n occurrences in the psql command's output to plain \n.
Then, the \r generated by pg_current_logfile() would butt up against the
line-ending \n, allowing the "fix" in sub psql to remove valid data.

One thing I noticed while making 91bdf499b is that some of these
substitutions are conditioned on "if $TestLib::windows_os" while others
are conditioned on "if $Config{osname} eq 'msys'".  What is the reason
for this difference?  Is it possible that we only really need to do it
in the latter case?

			regards, tom lane

Commits

  1. Tighten up Windows CRLF conversion in our TAP test scripts.

  2. Fix pg_current_logfile() to not emit a carriage return on Windows.

  3. Further tighten Windows CRLF conversion in our TAP test scripts.

  4. Add test coverage for pg_current_logfile() function.

  5. Fix failures to ignore \r when reading Windows-style newlines.

  6. Fix TAP infrastructure to support Mingw better