Re: Having problems generating a code coverage report

Hi,

On 2026-01-22 14:35:40 +0900, Michael Paquier wrote:
> On Wed, Jan 21, 2026 at 08:59:45PM -0500, Andres Freund wrote:
> > With that meson coverage information works (i.e. ninja coverage-html) for both
> > lcov 2.0 and 2.4 as long as the build directory is outside of the source
> > directory. Both on Debian Sid and macos.
>
> Thanks for sharing. Yes, I have a matching gcc version at 15.2
> currently. I have been playing with this area of the configuration
> for some time without finding the correct combination before giving
> up, and these suggestions are actually helping for meson. So now I
> can get a report offline. Yeah at least it's one thing working.

Cool.

> Hmm. configure with and without VPATH still burp at me on HEAD. If I
> tweak the lcov commands in src/Makefile.global.in like in the attached
> patch then the non-VPATH build can work, where I remove the srcdir
> part (aka reverting c3d9a66024a9). For the VPATH build, this patch
> does not work at all, it generates an incomplete report, ignoring
> entirely contrib/, with its base index.html starting inside src/,
> missing a bunch of subdirectories. I can live with this custom patch
> for now, just wondering if anybody else sees what I am seeing for a
> few months now.

If I suppress the empty errors & warnings with --ignore-errors empty,empty the
current "-d . -d $(srcdir)" kinda works. Unfortunately, in VPATH builds, the
directory structure is quite messed up. It seems to get a bit better if I add
-p $(srcdir) to the genhtml invocation, but a few generated files still show
up bogus.

The bogus build files unfortunately aren't trivial to fix, if I additionally
add a "-p $(pwd)" (i.e. add the build dir as a prefix), I get errors about
"duplicate merge record". But it's not too bad to see that stupid path for
the generated files.

Greetings,

Andres Freund