Diff of the two buildlogs:

--
--- b1/build.log	2024-11-10 05:15:50.688227662 +0000
+++ b2/build.log	2024-11-10 05:21:18.276598877 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Fri Dec 12 23:38:03 -12 2025
-I: pbuilder-time-stamp: 1765625883
+I: Current time: Sun Nov 10 19:15:54 +14 2024
+I: pbuilder-time-stamp: 1731215754
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/trixie-reproducible-base.tgz]
 I: copying local configuration
@@ -25,52 +25,84 @@
 dpkg-source: info: unpacking golang-github-teambition-rrule-go_1.8.1-2.debian.tar.xz
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/2723202/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/D01_modify_environment starting
+debug: Running on ionos1-amd64.
+I: Changing host+domainname to test build reproducibility
+I: Adding a custom variable just for the fun of it...
+I: Changing /bin/sh to bash
+'/bin/sh' -> '/bin/bash'
+lrwxrwxrwx 1 root root 9 Nov 10 05:16 /bin/sh -> /bin/bash
+I: Setting pbuilder2's login shell to /bin/bash
+I: Setting pbuilder2's GECOS to second user,second room,second work-phone,second home-phone,second other
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/D02_print_environment starting
 I: set
-  BUILDDIR='/build/reproducible-path'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
-  BUILD_ARCH='amd64'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=42 '
-  DISTRIBUTION='trixie'
-  HOME='/root'
-  HOST_ARCH='amd64'
+  BASH=/bin/sh
+  BASHOPTS=checkwinsize:cmdhist:complete_fullquote:extquote:force_fignore:globasciiranges:globskipdots:hostcomplete:interactive_comments:patsub_replacement:progcomp:promptvars:sourcepath
+  BASH_ALIASES=()
+  BASH_ARGC=()
+  BASH_ARGV=()
+  BASH_CMDS=()
+  BASH_LINENO=([0]="12" [1]="0")
+  BASH_LOADABLES_PATH=/usr/local/lib/bash:/usr/lib/bash:/opt/local/lib/bash:/usr/pkg/lib/bash:/opt/pkg/lib/bash:.
+  BASH_SOURCE=([0]="/tmp/hooks/D02_print_environment" [1]="/tmp/hooks/D02_print_environment")
+  BASH_VERSINFO=([0]="5" [1]="2" [2]="32" [3]="1" [4]="release" [5]="x86_64-pc-linux-gnu")
+  BASH_VERSION='5.2.32(1)-release'
+  BUILDDIR=/build/reproducible-path
+  BUILDUSERGECOS='second user,second room,second work-phone,second home-phone,second other'
+  BUILDUSERNAME=pbuilder2
+  BUILD_ARCH=amd64
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=20 '
+  DIRSTACK=()
+  DISTRIBUTION=trixie
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=x86_64
+  HOST_ARCH=amd64
   IFS=' 	
   '
-  INVOCATION_ID='d2445c37899e4031a17b3d6743cca772'
-  LANG='C'
-  LANGUAGE='en_US:en'
-  LC_ALL='C'
-  MAIL='/var/mail/root'
-  OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
-  PBCURRENTCOMMANDLINEOPERATION='build'
-  PBUILDER_OPERATION='build'
-  PBUILDER_PKGDATADIR='/usr/share/pbuilder'
-  PBUILDER_PKGLIBDIR='/usr/lib/pbuilder'
-  PBUILDER_SYSCONFDIR='/etc'
-  PPID='2723202'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=ccc36c7dd7d3427092ada82f95564f64
+  LANG=C
+  LANGUAGE=et_EE:et
+  LC_ALL=C
+  MACHTYPE=x86_64-pc-linux-gnu
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnu
+  PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path
+  PBCURRENTCOMMANDLINEOPERATION=build
+  PBUILDER_OPERATION=build
+  PBUILDER_PKGDATADIR=/usr/share/pbuilder
+  PBUILDER_PKGLIBDIR=/usr/lib/pbuilder
+  PBUILDER_SYSCONFDIR=/etc
+  PIPESTATUS=([0]="0")
+  POSIXLY_CORRECT=y
+  PPID=248596
   PS4='+ '
-  PWD='/'
-  SHELL='/bin/bash'
-  SHLVL='2'
-  SUDO_COMMAND='/usr/bin/timeout -k 18.1h 18h /usr/bin/ionice -c 3 /usr/bin/nice /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.kObCs6ep/pbuilderrc_dvKK --distribution trixie --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.kObCs6ep/b1 --logfile b1/build.log golang-github-teambition-rrule-go_1.8.1-2.dsc'
-  SUDO_GID='110'
-  SUDO_UID='105'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://213.165.73.152:3128'
+  PWD=/
+  SHELL=/bin/bash
+  SHELLOPTS=braceexpand:errexit:hashall:interactive-comments:posix
+  SHLVL=3
+  SUDO_COMMAND='/usr/bin/timeout -k 24.1h 24h /usr/bin/ionice -c 3 /usr/bin/nice -n 11 /usr/bin/unshare --uts -- /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.kObCs6ep/pbuilderrc_affX --distribution trixie --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.kObCs6ep/b2 --logfile b2/build.log golang-github-teambition-rrule-go_1.8.1-2.dsc'
+  SUDO_GID=110
+  SUDO_UID=105
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://46.16.76.132:3128
 I: uname -a
-  Linux ionos5-amd64 6.10.11+bpo-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.10.11-1~bpo12+1 (2024-10-03) x86_64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-26-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.112-1 (2024-09-30) x86_64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 Aug  4  2024 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/2723202/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Aug  4 21:30 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -151,7 +183,7 @@
 Get: 35 http://deb.debian.org/debian trixie/main amd64 golang-go amd64 2:1.23~2 [44.3 kB]
 Get: 36 http://deb.debian.org/debian trixie/main amd64 golang-any amd64 2:1.23~2 [5172 B]
 Get: 37 http://deb.debian.org/debian trixie/main amd64 tzdata-legacy all 2024b-3 [176 kB]
-Fetched 66.4 MB in 1s (100 MB/s)
+Fetched 66.4 MB in 5s (12.6 MB/s)
 debconf: delaying package configuration, since apt-utils is not installed
 Selecting previously unselected package tzdata.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 19969 files and directories currently installed.)
@@ -279,8 +311,8 @@
 Setting up tzdata (2024b-3) ...
 
 Current default time zone: 'Etc/UTC'
-Local time is now:      Sat Dec 13 11:38:31 UTC 2025.
-Universal Time is now:  Sat Dec 13 11:38:31 UTC 2025.
+Local time is now:      Sun Nov 10 05:18:13 UTC 2024.
+Universal Time is now:  Sun Nov 10 05:18:13 UTC 2024.
 Run 'dpkg-reconfigure tzdata' if you wish to change it.
 
 Setting up autotools-dev (20220109.1) ...
@@ -320,7 +352,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/golang-github-teambition-rrule-go-1.8.1/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-genchanges -S  > ../golang-github-teambition-rrule-go_1.8.1-2_source.changes
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for trixie
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/golang-github-teambition-rrule-go-1.8.1/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-genchanges -S  > ../golang-github-teambition-rrule-go_1.8.1-2_source.changes
 dpkg-buildpackage: info: source package golang-github-teambition-rrule-go
 dpkg-buildpackage: info: source version 1.8.1-2
 dpkg-buildpackage: info: source distribution unstable
@@ -338,54 +374,54 @@
    dh_autoreconf -O--builddirectory=_build -O--buildsystem=golang
    dh_auto_configure -O--builddirectory=_build -O--buildsystem=golang
    dh_auto_build -O--builddirectory=_build -O--buildsystem=golang
-	cd _build && go install -trimpath -v -p 42 github.com/teambition/rrule-go
-internal/coverage/rtcov
+	cd _build && go install -trimpath -v -p 20 github.com/teambition/rrule-go
 internal/race
-internal/unsafeheader
+internal/goarch
+internal/coverage/rtcov
 internal/godebugs
 internal/goexperiment
-internal/profilerecord
-internal/msan
+internal/cpu
 internal/itoa
-cmp
-internal/asan
+unicode
+internal/msan
+internal/profilerecord
 internal/goos
 math/bits
-internal/byteorder
 unicode/utf8
-unicode
-internal/goarch
 sync/atomic
-internal/cpu
+cmp
+internal/byteorder
+internal/asan
+internal/abi
+runtime/internal/math
 internal/runtime/syscall
 internal/runtime/atomic
-runtime/internal/math
+internal/unsafeheader
 runtime/internal/sys
-internal/abi
 internal/chacha8rand
 internal/bytealg
 math
 internal/runtime/exithook
 internal/stringslite
 runtime
-iter
 internal/reflectlite
+iter
 sync
 slices
-internal/testlog
 internal/bisect
+internal/testlog
 errors
 sort
-internal/godebug
+io
 internal/oserror
 path
-io
+internal/godebug
 strconv
 syscall
 strings
 reflect
-internal/syscall/execenv
 internal/syscall/unix
+internal/syscall/execenv
 time
 io/fs
 internal/poll
@@ -395,7 +431,7 @@
 fmt
 github.com/teambition/rrule-go
    dh_auto_test -O--builddirectory=_build -O--buildsystem=golang
-	cd _build && go test -vet=off -v -p 42 github.com/teambition/rrule-go
+	cd _build && go test -vet=off -v -p 20 github.com/teambition/rrule-go
 === RUN   TestNoDtstart
 --- PASS: TestNoDtstart (0.00s)
 === RUN   TestBadBySetPos
@@ -407,7 +443,7 @@
 === RUN   TestMonthlyMaxYear
 --- PASS: TestMonthlyMaxYear (0.00s)
 === RUN   TestWeeklyMaxYear
---- PASS: TestWeeklyMaxYear (0.06s)
+--- PASS: TestWeeklyMaxYear (0.14s)
 === RUN   TestInvalidRRules
 === RUN   TestInvalidRRules/Bysecond_under
 === RUN   TestInvalidRRules/Bysecond_over
@@ -939,7 +975,7 @@
 === RUN   TestUntil
 --- PASS: TestUntil (0.00s)
 === RUN   TestMaxYear
---- PASS: TestMaxYear (0.02s)
+--- PASS: TestMaxYear (0.12s)
 === RUN   TestBefore
 --- PASS: TestBefore (0.00s)
 === RUN   TestBeforeInc
@@ -953,7 +989,7 @@
 === RUN   TestBetweenInc
 --- PASS: TestBetweenInc (0.00s)
 === RUN   TestAllWithDefaultUtil
---- PASS: TestAllWithDefaultUtil (0.00s)
+--- PASS: TestAllWithDefaultUtil (0.01s)
 === RUN   TestWeekdayGetters
 --- PASS: TestWeekdayGetters (0.00s)
 === RUN   TestRuleChangeDTStartTimezoneRespected
@@ -997,7 +1033,7 @@
 === RUN   TestSetDtStart
 --- PASS: TestSetDtStart (0.00s)
 === RUN   TestRuleSetChangeDTStartTimezoneRespected
---- PASS: TestRuleSetChangeDTStartTimezoneRespected (0.00s)
+--- PASS: TestRuleSetChangeDTStartTimezoneRespected (0.01s)
 === RUN   TestRFCRuleToStr
 --- PASS: TestRFCRuleToStr (0.00s)
 === RUN   TestRFCSetToString
@@ -1047,7 +1083,7 @@
 === RUN   ExampleStrToRRuleSet
 --- PASS: ExampleStrToRRuleSet (0.00s)
 PASS
-ok  	github.com/teambition/rrule-go	0.105s
+ok  	github.com/teambition/rrule-go	0.388s
    create-stamp debian/debhelper-build-stamp
    dh_testroot -O--builddirectory=_build -O--buildsystem=golang
    dh_prep -O--builddirectory=_build -O--buildsystem=golang
@@ -1074,12 +1110,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: not including original source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/248596/tmp/hooks/B01_cleanup finished
 I: unmounting dev/ptmx filesystem
 I: unmounting dev/pts filesystem
 I: unmounting dev/shm filesystem
 I: unmounting proc filesystem
 I: unmounting sys filesystem
 I: cleaning the build env 
-I: removing directory /srv/workspace/pbuilder/2723202 and its subdirectories
-I: Current time: Fri Dec 12 23:38:49 -12 2025
-I: pbuilder-time-stamp: 1765625930
+I: removing directory /srv/workspace/pbuilder/248596 and its subdirectories
+I: Current time: Sun Nov 10 19:21:17 +14 2024
+I: pbuilder-time-stamp: 1731216077