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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
cc: Alvaro Herrera <alvherre@alvh.no-ip.org>,
        Stephen Frost <sfrost@snowman.net>,
        Magnus Hagander <magnus@hagander.net>,
        PostgreSQL WWW <pgsql-www@lists.postgresql.org>
Subject: Re: Bogus reports from coverage.postgresql.org
In-reply-to: <5744.1521045105@sss.pgh.pa.us>
References: <20180314154352.ao4psdohgxd4pw65@alvherre.pgsql>
 <4710.1521044117@sss.pgh.pa.us> <5744.1521045105@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Wed, 14 Mar 2018 12:31:45 -0400"
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Date: Wed, 14 Mar 2018 12:46:39 -0400
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I wrote:
> Our process swaps steps 1 and 2.  What I now suspect is that
> we accidentally get away with that for basic mode, but it
> doesn't work with lcov_branch_coverage.

I tested that theory by manually doing things in the "correct" order,
and it didn't change the results:

$ /usr/bin/lcov --gcov-tool /usr/bin/gcov -q --no-external -c -i -d . -d .=
 -o lcov_base.info
geninfo: Note: --initial does not generate branch coverage data
$ make check
...
$ /usr/bin/lcov --gcov-tool /usr/bin/gcov -q --no-external -c -d . -d . -o=
 lcov_test.info
$ rm -rf coverage
$ /usr/bin/genhtml -q --legend -o coverage --title=3D'PostgreSQL 11devel' =
--num-spaces=3D4 --prefix=3D'/home/tgl/pgsql' lcov_base.info lcov_test.inf=
o
$ grep bogus  coverage/src/backend/optimizer/util/predtest.c.*
coverage/src/backend/optimizer/util/predtest.c.gcov.html:<span class=3D"li=
neNum">     492 </span>                :<span class=3D"lineCov">      1018=
6 :     elog(ERROR, &quot;predicate_classify returned a bogus value&quot;)=
;</span>
coverage/src/backend/optimizer/util/predtest.c.gcov.html:<span class=3D"li=
neNum">     803 </span>                :<span class=3D"lineCov">      5948=
2 :     elog(ERROR, &quot;predicate_classify returned a bogus value&quot;)=
;</span>

I'm still a bit suspicious that we may have a process problem,
but it's looking like there may be grounds for an lcov bug
report.

			regards, tom lane