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<p><font size="-1">Not sure what the rush is. Ubuntu 20.04 will be
available in a month with cmake 3.16.3 which appears to be
recent enough to handle the issues indicated. Those on older
distributions should upgrade as soon as they can and though that
may take a few months, getting that coordinated all around does
not seem that unreasonable.</font></p>
<p><font size="-1">The idea of downloading and installing individual
pieces of software that are not verified through the
distribution process has been discouraged for over a decade.
Modern computer systems are far too complex including time and
money to be taking unnecessary risks. The argument is never how
easy it is to turn your computer into a boat anchor. It is what
are the risks against the gain.</font></p>
<p><font size="-1">The gain could well be worth it. But without
recognizing the risks there is no argument for gain. That others
take risks we can avoid is not a good argument.</font></p>
<p><font size="-1">As an aside, a few days ago my new, custom built
computer would not complete boot when it was just fine the day
before and I was thinking: was it the Xubuntu update, was it my
change to fstab, did my nvme ssd die, did I just toast several
weeks of work, will my computer live again. It is not a happy
situation.<br>
</font></p>
<p><font size="-1">Neil Nelson<br>
</font></p>
<div class="moz-cite-prefix"><font size="-1">On 3/26/20 9:03 AM,
Nico Weber via llvm-dev wrote:<br>
</font></div>
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cite="mid:CAMGbLiEmQ8eXHhkt6BpyJABPfymeN_Jp-SND4fguTyk6ew7O7A@mail.gmail.com"><font
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<div class="gmail_quote">
<div><font size="-1">FWIW, I agree that it's easy to install a
non-system cmake and using that (we do this on all our
bots, and it's what people have to do on mac and windows
already)), and that "what is available in LTS distros"
shouldn't hold things up.</font></div>
<div><font size="-1"><br>
For the actual rollout process, I could imagine that most
folks would miss the phab. So I'd suggest what we've done
for similar changes in the past:</font></div>
<div><font size="-1"><br>
</font></div>
<div><font size="-1">1. Land a change that makes using an
older cmake an error that goes like "We'll require cmake
$version soon. You can define
LLVM_SUPPRESS_CMAKE_$version_ERROR to turn this into a
warning for a few weeks, but update your bots soon"</font></div>
<div><font size="-1"><br>
</font></div>
<div><font size="-1">2. Wait 2-4 weeks</font></div>
<div><font size="-1"><br>
</font></div>
<div><font size="-1">3. Make the error unconditional (and
remove the wording about the suppression).</font></div>
<div><font size="-1"> </font></div>
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