---
layout: default
title: Release Notes - Mock v5.0
---

Released on 2023-08-09.

## Mock v5.0 new features:

- The `use_bootstrap_image` feature has been turned on as it was stabilized in
  this release and it speeds up the bootstrap chroot preparation a lot
  (by not installing potentially hundreds of packages into the bootstrap chroot,
  but just extracting the `bootstrap_image` contents).  For the RHEL based chroots
  (where UBI `bootstrap_image` is in use, and where `python3-dnf-plugins-core`
  is installed by default) we also turned on the `bootstrap_image_ready=True`
  which drastically speeds the bootstrap preparation.  See the explanation for
  `bootstrap_image_ready` below.  See [PR#1101][] for more info.

- Start using `useradd` and `userdel` utilities from the host to modify
  in-chroot `etc/passwd` and `etc/group`.  This allowed us to remove
  the `shadow-utils` package from the list of "minimal buildroot" packages
  ([issue#1102][]).

- There's a new feature `config_opts['copy_host_users'] = ['pesign', ...]` that
  allows users to specify a list of users to pre-create in buildroot, copying
  the IDs from the host.  Users/groups used to be historically created by
  post-scriptlets from the buildroot packages, but the user/group IDs often did
  not match the IDs on the host - possibly causing weird and hard to fix issues
  similar to the [Pesign one][issue#1091].

- Make sure the `/dev/fuse` device is available in Mock buildroot with
  `--isolation=nspawn`.  Without this device, we could not use FUSE filesystems
  with image builds ([PR#1158][] and the [Fedora Infra issue][fuseInfra]).

- New option `config_opts['bootstrap_image_ready'] = True|False` was invented.
  When set to `True`, Mock doesn't try to do any package manager actions inside
  bootstrap (normally Mock installs `dnf` tooling there).  It simply assumes
  that the bootstrap image is ready to use (that the `dnf` tooling is already
  installed on the image).  This might fix hard-to-debug/hard-to-fix issues like
  [issue#1088][] when an unexpected bootstrap image is used. This option is
  enabled by default for RHEL 8 and 9 chroots only.

- The Podman container environment is able to automatically pass down the Red
  Hat Subscription credentials anytime a RHEL-based (UBI) container is run.  But
  the credential files are then on different path than when run natively on
  the host, and that used to break Mock.  Newly, when Mock is run in a Podman
  container, the credentials passed down by Podman are automatically detected
  and used ([PR#1130][]).

- Even though the requested buildroot is cross-arch (must be initialized with
  cross-arch packages using the `--forcearch RPM` feature), the bootstrap chroot
  is newly always prepared with the native architecture.  This change has been
  done to optimize the final buildroot installation — using the "arch natively"
  compiled DNF stack is much faster than cross-arch emulation using
  `qemu-user-static`.  As a benefit, we can newly simply use the "native"
  Podman-pulled `bootstrap_image` even for cross-arch builds (we have to play
  with Glibc's "personality" a bit, but still).  See [issue#1110][].

- The bootstrap-related logging has been changed so the corresponding log
  entries are now appended to the default `root.log` file.  This change should
  lead to a better understanding what is going on in the bootstrap chroot
  ([issue#539][] and [PR#1106][]).

- An easier way to skip Mock plugin execution in Bootstrap chroot has been
  invented.  It is now enough to just specify `run_in_bootstrap = False` global
  variable in such a plugin, see [PR#1116][] for more info.  The plugin
  `hw_info` has been newly disabled this way.

- The bootstrap chroot installation was made smaller;  newly only the
  `python3-dnf` and `python3-dnf-plugins-core` are installed, instead of `dnf`
  and `dnf-plugins-core` (which used to install also unnecessary documentation
  files).

- Automatic file downloads (for example with `mock https://exmaple.com/src.rpm`
  use cases) have been changed to automatically retry the download several times
  to work around random network failures ([PR#1132][] and [PR#1134][]).

- The `dnf` and `dnf5` processes are newly always executed with the
  `--setopt=allow_vendor_change=yes` option.  This is done in belief that we
  don't have to protect the Mock builds against `Vendor:` changes, while
  overriding the distro-default RPMs is quite a common thing (`mock --chain`
  e.g.) while mimicking the distro-default `Vendor` tag would be a painful task.
  The thing is that the `allow_vendor_change=no` is going to be set by default
  in DNF5 soon and we want to prevent unnecessary surprises.  Also, openSUSE has
  been reported to use this even with DNF4 ([PR#1160][]).

- Mock now considers DNF5 to be a valid package manager alternative.  For
  example considering

    1. that Bootstrap chroot is generated from a bootstrap image,
    2. expected package manager is DNF4 (`package_manager == 'dnf'`)
    3. but the selected image has only `dnf5` installed by default

  then Mock properly finds the `/bin/dnf5` command in-bootstrap, uses it to
  install `/bin/dnf-3` into the bootstrap chroot first and then it uses
  `/bin/dnf-3` in bootstrap for the final target buildroot installation.


## Mock v5.0 bugfixes:

- The orphan-process killing feature was enhanced to also properly kill
  processes started by `dnf install` post-scriptles (installing from bootstrap
  to buildroot), see [issue#1165][].

- The `podman pull` logic that Mock does in the background with
  `--use-bootstrap-image` (now by default) was fixed to not affect the
  `mock --shell` stdout.  That was a bug, stdout is often parsed by callers.

- The fact that we use in-bootstrap package manager for *installation stuff into
  the bootstrap chroot itself* revealed that we have to do certain mountpoints
  [earlier than we used to][PR#1167].

- Make sure we properly unmount all the Mock mount internal points even though
  the Mock process was interrupted using `CTRL+C` (`KeyboardInterrupt`
  exception).  This has fixed a long-term observed bug that kept things mounted
  longer than necessary, eventually breaking even subsequent `mock --scrub`
  attempts.  Also, the internal directory removal method has been fixed to
  *try its job harder* under [certain circumstances][PR#1058]. Relates to
  [rhbz#2176689][], [rhbz#2176691][], [rhbz#2177680][], [rhbz#2181641][], etc.

- Python `imp` module was removed from Python 3.12, so the code was migrated to
  `importlib`, [issue#1140][].

- Automatic SRPM downloads from the web were handling the file names specified
  by HTTP headers using the long-time deprecated `cgi` module.  The module is
  being dropped from Python v3.13 so Mock 5.0 has been fixed to use
  `email.message` library which now provides the same functionality
  ([PR#1134][]).

- The default recursion limit for Python scripts is set to 1000 (for non-root
  users); this hasn't been enough for Mock in some use-cases so the limit has
  been increased in v5.0+.  For example, some utilities have directory-tree
  stress-tests their test suites, and for such cases a very large directory tree
  can cause too deep recursive calls of the `shutil.rmtree()` method.  Users
  can newly also override the Mock's default via the
  `config_opts["recursion_limit"]` option.

- Mock newly never uses the `--allowerasing` option with the `dnf5 remove`
  command (this option has not been implemented in DNF5 and DNF5 simply fails,
  contrary to the old DNF4 code where it was implemented a no-op,
  [issue#1149][]).

- The SSL certificate copying has been fixed [once more][PR#1113] to use our own
  `update_tree()` logic because the `distutils.copy_tree()` was removed from the
  Python stdlib, and the new stdlib alternative `shutil.copytree()` is not
  powerful enough for the Mock use-cases ([issue#1107][]).

- Mock no longer dumps the long output of the `rpmbuild --help` command into
  `build.log`, fixes [issue#999][].

## mock-core-configs v39 changes:

- Fedora 39 configuration is branched from Rawhide, as branching date
  is [2023-08-08](https://fedorapeople.org/groups/schedule/f-39/f-39-all-tasks.html).

- The new `mock-core-configs` package is not compatible with older Mock
  versions, therefore the requirement was bumped to `v5.0` or newer.

- Started using `bootstrap_image_ready = True` for RHEL-based configs as UBI
  images contain all the necessary DNF tooling by default ([PR#1101][]).

- Disable `use_bootstrap_image` for the Mageia chroots;  Mageia doesn't provide
  an officially supported (and working) container images that we could set in
  the `bootsrap_image` config option ([issue#1111][]).

- Dropped the `config_opts['useradd']` option from all the configs; the
  `useradd` utility from now on always executed on the host (not in chroot) with
  the `--prefix <chrootRoot>` options ([issue#1102][]).

- Using `$releasever` in openEuler metalink URLs.

- Several configuration files were updated to work correctly with the new
  `use_bootstrap_image = True` in Mock 5.0.  Relates to [issue#1171][]


**Following contributors contributed to this release:**

 * Miro Hrončok
 * Miroslav Suchý
 * Neal Gompa
 * zengwei2000
 * zengchen1024

Thank you.

[PR#1058]: https://github.com/rpm-software-management/mock/pull/1058
[PR#1101]: https://github.com/rpm-software-management/mock/pull/1101
[PR#1106]: https://github.com/rpm-software-management/mock/pull/1106
[PR#1113]: https://github.com/rpm-software-management/mock/pull/1113
[PR#1116]: https://github.com/rpm-software-management/mock/pull/1116
[PR#1130]: https://github.com/rpm-software-management/mock/pull/1130
[PR#1132]: https://github.com/rpm-software-management/mock/pull/1132
[PR#1134]: https://github.com/rpm-software-management/mock/pull/1134
[PR#1158]: https://github.com/rpm-software-management/mock/pull/1158
[PR#1158]: https://github.com/rpm-software-management/mock/pull/1160
[PR#1167]: https://github.com/rpm-software-management/mock/pull/1167
[issue#539]: https://github.com/rpm-software-management/mock/issues/539
[issue#999]: https://github.com/rpm-software-management/mock/issues/999
[issue#1088]: https://github.com/rpm-software-management/mock/issues/1088
[issue#1091]: https://github.com/rpm-software-management/mock/issues/1091
[issue#1102]: https://github.com/rpm-software-management/mock/issues/1102
[issue#1107]: https://github.com/rpm-software-management/mock/issues/1107
[issue#1110]: https://github.com/rpm-software-management/mock/issues/1110
[issue#1111]: https://github.com/rpm-software-management/mock/issues/1111
[issue#1140]: https://github.com/rpm-software-management/mock/issues/1140
[issue#1149]: https://github.com/rpm-software-management/mock/issues/1149
[issue#1165]: https://github.com/rpm-software-management/mock/issues/1165
[issue#1171]: https://github.com/rpm-software-management/mock/issues/1171
[rhbz#2176689]: https://bugzilla.redhat.com/2176689
[rhbz#2176691]: https://bugzilla.redhat.com/2176691
[rhbz#2177680]: https://bugzilla.redhat.com/2177680
[rhbz#2181641]: https://bugzilla.redhat.com/2181641
[fuseInfra]: https://pagure.io/fedora-infrastructure/issue/11420