Re: 13.4 compiles firefox functionally different

On Tue, Sep 17, 2024 at 08:35:59AM -0500, Dan Mack wrote:
! On Tue, 17 Sep 2024, Peter wrote:
! 
! > Hi,
! > 
! > after upgrading to 13.4-RC2-p1, I recompiled all ports.
! > 
! > Today I found my firefox can no longer render a certain webpage;
! > the output is garbled as if the CSS were missing/defective.
! > Here is details and picture:
! > https://forums.freebsd.org/threads/firefox-displays-unintellegible-garbage-only-on-freebsd.94963/post-671994
! > 
! > The firefox version is -esr-115.15.0,1, from 2024Q3 as of a
! > week ago.
! > 
! > Investigation showed:
! > * firefox from package as of today (130.something) works well.
! > * firefox-esr from package as of today (128.something) works
! >   well.
! > * firefox-esr from ports as of today (128.2.0esr) freshly compiled
! >   on 13.4-RC2-p1 also works well (prereqs still from last week)
! > * firefox-esr 115.14.0_1,1 locally compiled a few weeks ago on
! >   Rel. 13.3 also works well.
! > 
! > So I did verify: I restarted a Rel.13.3-p5, fetched all
! > prereqisite ports from backup (so these were also compiled on 13.3),
! > and then compiled firefox-esr-115.15.0,1, the very same that now
! > renders garbage, using the very same ports tree, with OS running
! > 13.3-p5. And that one now works!
! > 
! > So bottomline is:
! > firefox-esr 115.15.0,1 - the one that was in 2024Q3 until about a
! > week ago - works correct when compiled on 13.3 (along with all it's
! > prereq ports), but renders garbage for a certain webpage when
! > compiled on 13.4-RC2 (along with all it's prereq ports).
! > 
! > I don't like this, because now the question is: what else might 13.4
! > compile so that it suddenly functions differently?
! > 
! > 
! > (I glanced thru PR 277021 - but it doesn't seem to mention anything
! > about webpages displaying broken, or any functional difference)
! > 
! > Any idea how this might come to happen, anybody?
! 
! Probably not related but I'll bring it up anyway; there was issue with
! firefox/other programs on alpine linux a couple weeks ago where the MESA
! package's upgrade in combination with using the link time optimization
! feature under gcc-14.x caused garbled previews and other graphical anomolies
! on my Firefox and my sway window manager.

Hi Dan,

  thanks for Your feedback. This reflects what I happen to say: we're
sitting on a huge pile of code, and almost nobody does still
understand all the possible interdependencies - we only hunt them when
something does visibly malfunction.

In my case, this specific webpage brings along some 40k lines of CSS
code, and from what I could figure out, firefox downloads them
successfully, but then after a few hundred lines they are not applied
any further.

! Not sure which compiler / mesa is used to build firefox on FreeBSD but could
! be part of the problem I guess or a place to look at the dependencies.  It
! looks like they disabled LTO on the mesa build to fix the issue.  That was
! using mesa-24.2.2.

Firefox builds rust and llvm-17 from ports as prereq. It could be that
these work someway different when built on 13.4. And that is exactly
where my belly starts hurting: these compilers are used for other
software too.