Corrupted debug output in brew update

To help us debug your issue please explain:

What you were trying to do (and why) doing a brew update
What happened (include command output) The output begins with corrupted debug messages, and brew update completes successfully.

Failed to set filetime 1508952642 on outfile: errno 1
Failed to set filetime 1518769013 on outfile: errno 1
Failed to set filetime 1518177856 on outfile: errno 1
FaiFFlaaeiidll eetdod   tstoeo t s sefetitl  efftiiillmeeett ii1mm5ee1  8118447977130345114 40o75n09 12o u otonF nfo iuolatuefit:l feiidellreer ::nt  ooee rr rrsnn1eoot
   f11i

letime 1514800155 on outfile: errno 1
FaFilaeidl etdo  tsoe ts efti lfeitliemtei m1e4 9115107198185656 7o6n  Fooanui tlofeuidtl feit:ol e :s eetr refnriorl n1eo
 t1i
me 1518862042 on outfile: errno 1

Updated Homebrew from 021fe22e3c to ef1924e1f3.
Updated 2 taps (caskroom/cask, homebrew/core).
==> New Formulae
calicoctl         console_bridge    dashing           fcl               futhark           grv               libsbol           odpi              srt               tomcat@8          urdfdom_headers
clblast           dartsim           dynare            fruit             gpredict          libdill           ocrmypdf          openimageio       terraforming      urdfdom           webtorrent-cli
==> Updated Formulae
awscli ✔              bazel                 dub                   ginac                 joplin                lumo                  paket                 rustup-init           swiftformat
ffmpeg ✔              bcftools              duck                  git-archive-all       juju                  lynis                 pandoc-citeproc       s-nail                swiftlint
git ✔                 binaryen              emscripten            git-fresh             just                  lzip                  pdns                  s3-backer             sword
gnutls ✔              bitrise               erlang                glpk                  jvgrep                lzlib                 percona-server@5.6    sagittarius-scheme    systemc
go ✔                  blast                 etcd                  godep                 jvm-mon               magic-wormhole        pgpool-ii             sbt@0.13              taisei
irssi ✔               bro                   feh                   gomplate              kallisto              mame                  picard-tools          scala@2.10            teleport
leptonica ✔           buildapp              ffmpeg@2.8            googler               kedge                 mariadb               pilosa                sceptre               tomee-webprofile
mpv ✔                 burp                  fio                   gource                knot                  mas                   pipenv                sfk                   traefik
ocaml ✔               c-ares                flow                  grakn                 knot-resolver         math-comp             plank                 simg2img              twarc
youtube-dl ✔          camlp5                fluent-bit            gsoap                 kobalt                mdcat                 plzip                 singular              typescript
acmetool              ccache                fn                    gtk+3                 kompose               memcached             postgresql@9.4        skafos                uwsgi
advancecomp           chakra                folly                 gutenberg             kops                  metricbeat            pspg                  sonarqube             vala
allure                chronograf            forego                haxe                  landscaper            monetdb               py2cairo              sphinx-doc            vdirsyncer
angular-cli           cimg                  freetds               heroku                latex2html            mpc                   py3cairo              sslh                  vert.x
aqbanking             clhep                 frugal                hugo                  libav                 mpd                   qemu                  statik                vim
asciinema             coq                   fuse-zip              iperf3                libgee                node@6                qt                    stk                   wtf
asdf                  coreos-ct             gcovr                 javarepl              libgtop               ocaml-num             questdb               stlink                x3270
aws-elasticbeanstalk  ddrescue              gdnsd                 jenkins               libmpdclient          ocamlsdl              quicktype             storm                 xtensor
azure-cli             diamond               gecode                jenkins-lts           libpqxx               ooniprobe             recon-ng              supervisor            yle-dl
bareos-client         dmd                   get-flash-videos      jfrog-cli-go          libxlsxwriter         opendetex             ripgrep               surfraw
baresip               dnscrypt-wrapper      geth                  jmeter                logstalgia            osm2pgrouting         rust                  suricata
==> Deleted Formulae
tomcat@8.0

What you expected to happen brew update works as expected, but begins with the corrupted text output.
Step-by-step reproduction instructions (by running brew commands) brew update

brew config

HOMEBREW_VERSION: 1.5.4-46-gef1924e
ORIGIN: https://github.com/Homebrew/brew.git
HEAD: ef1924e1f3f2becefe68e4ee6c3967eeee998fcf
Last commit: 30 hours ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 0ae55471560ee89bb590f244354e5e3deb6d55ff
Core tap last commit: 5 minutes ago
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: --require-sha
HOMEBREW_DEV_CMD_RUN: 1
HOMEBREW_NO_ANALYTICS: 1
HOMEBREW_NO_AUTO_UPDATE: 1
HOMEBREW_NO_GITHUB_API: 1
HOMEBREW_NO_INSECURE_REDIRECT: 1
CPU: octa-core 64-bit haswell
Homebrew Ruby: 2.3.3 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.3.3/bin/ruby
Clang: 8.1 build 802
Git: 2.15.1 => /usr/local/bin/git
Curl: 7.54.0 => /usr/bin/curl
Perl: /usr/bin/perl
Python: /usr/local/opt/python/libexec/bin/python => /usr/local/Cellar/python/2.7.13_1/Frameworks/Python.framework/Versions/2.7/bin/python2.7
Ruby: /Users/w/.rvm/rubies/ruby-2.4.1/bin/ruby
Java: N/A
macOS: 10.12.6-x86_64
Xcode: N/A
CLT: 8.3.2.0.1.1492020469
X11: 2.7.6 => /opt/X11

brew doctor


Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: A newer Command Line Tools release is available. Update them from Software Update in the App Store.

Warning: Unbrewed header files were found in /usr/local/include. If you didn't put them there on purpose they could cause problems when building Homebrew formulae, and may need to be deleted.

Unexpected header files: /usr/local/include/jsmn.h

Warning: Unbrewed static libraries were found in /usr/local/lib. If you didn't put them there on purpose they could cause problems when building Homebrew formulae, and may need to be deleted.

Unexpected static libraries: /usr/local/lib/libjsmn.a

Warning: You have unlinked kegs in your Cellar Leaving kegs unlinked can lead to build-trouble and cause brews that depend on those kegs to fail to run properly once built. Run brew link on these: imagemagick

Warning: You have a curlrc file If you have trouble downloading packages with Homebrew, then maybe this is the problem? If the following command doesn't work, then try removing your curlrc: curl https://github.com

Warning: Your XQuartz (2.7.6) is outdated. Please install XQuartz 2.7.11 (or delete the current version). XQuartz can be updated using Homebrew-Cask by running brew cask reinstall xquartz

Warning: Some keg-only formulae are linked into the Cellar. Linking a keg-only formula, such as gettext, into the cellar with brew link <formula> will cause other formulae to detect them during the ./configure step. This may cause problems when compiling those other formulae.

Binaries provided by keg-only formulae may override system binaries with other strange results.

You may wish to brew unlink these brews: gettext

Homebrew / brew

Corrupted debug output in brew update #3814