Make "dnf4" equivalent to "dnf"

And while on it, unify the `system_PM_command` with the rest of
PM-specific commands.

Fixes: rpm-software-management#1271

mock/docs/site-defaults.cfg

@@ -91,10 +91,12 @@
 # variable use_container_host_hostname or %_buildhost macro can override this
 # config_opts['hostname'] = 'my.own.hostname'
 
-# The default package manager is DNF
-# config_opts['package_manager'] = 'dnf'
-# If you want to use DNF, set it to 'dnf'. To use DNF you need to have dnf and
-# dnf-plugins-core installed
+# The default package manager is DNF4.  The options are:
+# - 'dnf4' for DNF4 (Python) https://github.com/rpm-software-management/dnf
+# - 'dnf5' for DNF5 (C++) https://github.com/rpm-software-management/dnf5
+#   The major version of DNF5 will remain '5' indefinitely, see #1271.
+# - 'yum' for YUM https://github.com/rpm-software-management/yum
+#config_opts['package_manager'] = 'dnf4'
 
 # Number of attempts to execute package manager's action, and delay between
 # attempts (seconds).  This is useful e.g. if the build is done against
@@ -131,12 +133,9 @@
 # "bootstrap" chroot we initialize the target chroot.
 #config_opts['use_bootstrap'] = True
 
-#config_opts['system_yum_command'] = '/usr/bin/yum'
-#config_opts['system_dnf_command'] = '/usr/bin/dnf'
-
 # The bootstrap chroot is normally installed using a package manager from host,
 # but in some cases even this isn't possible (e.g. installing rather new ZSTD
-# compressed dnf.rpm package by 'dnf_install_command' on epel-7 host).  In such
+# compressed dnf.rpm package by 'dnf4_install_command' on epel-7 host).  In such
 # case, you may need to have "bootstrap" chroot pre-populated from a container
 # image first (where the package manager stack is already pre-installed, so
 # mock doesn't have to).
@@ -476,7 +475,7 @@
 #
 # You can configure how DNF (and other packager managers) will be used with
 # Mock.  Each option is specific to a concrete package manager, and then it
-# is appropriately prefixed by <pm_pfx>, namely `dnf5_`, `dnf_`, `yum_` or
+# is appropriately prefixed by <pm_pfx>, namely `dnf5_`, `dnf4_`, `yum_` or
 # `microdnf_`.  Mock attempts to use appropriate package manager depending on
 # the `package_manager` configuration option.
 #
@@ -487,6 +486,11 @@
 #       path, searched both on host (to install bootstrap chroot) or in
 #       bootstrap chroot (to install buildroot)
 #
+# '<pm_pfx>_system_command' (e.g. yum_system_command) - the package manager
+#       executable searched on host only in case of <pm_pfx>_command not found.
+#       This may be useful for "bootstrap=off" scenarios with the package
+#       manager installed in a custom location.
+#
 # '<pm_pfx>_common_opts' (e.g. dnf5_common_opts) - options that are passed to
 #       every single command execution of the '<pm_pfx>_command' by Mock, minus
 #       '_avoid_opts', see below
@@ -508,7 +512,7 @@
 #       might want to use 'use_bootstrap_image' instead (then bootstrap chroot
 #       is just "downloaded", not installed).
 #
-# '<pm_pfx>_disable_plugins (e.g. dnf_disable_plugins) - list of package
+# '<pm_pfx>_disable_plugins (e.g. dnf4_disable_plugins) - list of package
 #       manager plugins that should be always disabled when Mock executes the
 #       '<pm_pfx>_command' (e.g. versionlock, with Mock we always want to build
 #       against the latest package versions available in buildroot)
@@ -518,29 +522,36 @@
 #       build dependencies.  There's no 'yum builddep' (sub)command though,
 #       but /bin/yum-builddep.  Use this option to override the default.
 #
-# '<pm_pfx>_builddep_opts (e.g. dnf_builddep_opts) - list of additional
+# '<pm_pfx>_builddep_opts (e.g. dnf5_builddep_opts) - list of additional
 #       options to always use with the builddep command
 
-# DNF (or DNF4, Python) - https://github.com/rpm-software-management/dnf
-#config_opts['dnf_command'] = '/usr/bin/dnf-3'
-#config_opts['dnf_common_opts'] = ['--setopt=deltarpm=False', '--setopt=allow_vendor_change=yes', '--allowerasing']
-# DF5 sub-command 'builddep' doesn't support the '--allowerasing' option:
-# https://github.com/rpm-software-management/dnf5/issues/461
-#config_opts["dnf5_avoid_opts"] = {"builddep": ["--allowerasing"]}
-#config_opts['dnf_install_command'] = 'install python3-dnf python3-dnf-plugins-core'
-#config_opts['dnf_disable_plugins'] = ['local', 'spacewalk', 'versionlock']
-#config_opts['dnf_builddep_opts'] = []
+# DNF4 specific options (Fedora <= 39, EL 8, 9 and 10)
+#
+# Don't be confused by the '-3' suffix in the DNF4 script.  This is a
+# historical artifact from when it was necessary to differentiate between
+# 'Python 3' and 'Python 2' scripts.
+#config_opts['dnf4_command'] = '/usr/bin/dnf-3'
+#config_opts['dnf4_system_command'] = '/usr/bin/dnf'
+#config_opts['dnf4_common_opts'] = ['--setopt=deltarpm=False', '--setopt=allow_vendor_change=yes', '--allowerasing']
+#config_opts['dnf4_install_command'] = 'install python3-dnf python3-dnf-plugins-core'
+#config_opts['dnf4_disable_plugins'] = ['local', 'spacewalk', 'versionlock']
+#config_opts['dnf4_builddep_opts'] = []
 
-# DNF5 (DNF4 re-written in C++) https://github.com/rpm-software-management/dnf5
-# Known issue with DNF5: --forcearch is not supported by DNF5
-# https://github.com/rpm-software-management/dnf5/issues/112
+# DNF5 specific options (Fedora 40+ https://fedoraproject.org/wiki/Changes/BuildWithDNF5)
+#
 #config_opts['dnf5_command'] = '/usr/bin/dnf5'
+#config_opts['dnf5_system_command'] = '/usr/bin/dnf5'
 #config_opts['dnf5_common_opts'] = ['--setopt=deltarpm=False', '--setopt=allow_vendor_change=yes', '--allowerasing']
 #config_opts['dnf5_install_command'] = 'install dnf5 dnf5-plugins'
 #config_opts['dnf5_disable_plugins'] = []
+# DF5 sub-command 'builddep' doesn't support the '--allowerasing' option:
+# https://github.com/rpm-software-management/dnf5/issues/461
+#config_opts["dnf5_avoid_opts"] = {"builddep": ["--allowerasing"]}
 
 # YUM (for RHEL7 and older) - https://github.com/rpm-software-management/yum
+#
 #config_opts['yum_command'] = '/usr/bin/yum'
+#config_opts['yum_system_command'] = '/usr/bin/yum'
 #config_opts['yum_common_opts'] = []
 #config_opts['yum_install_command'] = 'install yum yum-utils'
 #config_opts['yum_builddep_command'] = '/usr/bin/yum-builddep'

mock/integration-tests/setup-playbook/tasks/main.yml

@@ -3,6 +3,10 @@
   community.general.copr:
     name: '@mock/mock-stable'
 
+- name: up2date mock dependencies
+  community.general.copr:
+    name: '@mock/mock-deps'
+
 - name: install mock and other needed packages
   package: name={{ packages }} state=latest
   vars:

mock/mock.spec

@@ -53,7 +53,7 @@ Requires: python%{python3_pkgversion}-jinja2
 Requires: python%{python3_pkgversion}-requests
 Requires: python%{python3_pkgversion}-rpm
 Requires: python%{python3_pkgversion}-pyroute2
-Requires: python%{python3_pkgversion}-templated-dictionary
+Requires: python%{python3_pkgversion}-templated-dictionary >= 1.5
 Requires: python%{python3_pkgversion}-backoff
 BuildRequires: python%{python3_pkgversion}-backoff
 BuildRequires: python%{python3_pkgversion}-devel

mock/py/mockbuild/config.py

@@ -51,7 +51,19 @@ def nspawn_supported():
 @traceLog()
 def setup_default_config_opts():
     "sets up default configuration."
-    config_opts = TemplatedDictionary(alias_spec={'dnf.conf': ['yum.conf', 'dnf5.conf']})
+
+    alt_opts = {'dnf.conf': ['yum.conf', 'dnf5.conf', 'dnf4.conf']}
+    for alt in ["dnf_command", "dnf_common_opts", "dnf_install_command",
+                "dnf_disable_plugins", "dnf_avoid_opts"]:
+        alt_opts[alt.replace("dnf", "dnf4")] = alt
+
+    for pm in ["dnf4", "dnf5", "yum", "microdnf"]:
+        alt_opts[f"{pm}_system_command"] = [f"system_{pm}_command"]
+
+    alt_opts["dnf4_system_command"].append("system_dnf_command")
+
+    config_opts = TemplatedDictionary(alias_spec=alt_opts)
+
     config_opts['config_paths'] = []
     config_opts['version'] = VERSION
     config_opts['basedir'] = '/var/lib/mock'  # root name is automatically added to this
@@ -318,20 +330,20 @@ def setup_default_config_opts():
 
     # configurable commands executables
     config_opts['yum_command'] = '/usr/bin/yum'
-    config_opts['system_yum_command'] = '/usr/bin/yum'
+    config_opts['yum_system_command'] = '/usr/bin/yum'
     config_opts['yum_install_command'] = 'install yum yum-utils'
     config_opts['yum_builddep_command'] = '/usr/bin/yum-builddep'
     config_opts["yum_avoid_opts"] = {}
 
-    config_opts['dnf_command'] = '/usr/bin/dnf-3'
-    config_opts['system_dnf_command'] = '/usr/bin/dnf-3'
-    config_opts['dnf_common_opts'] = ['--setopt=deltarpm=False', '--setopt=allow_vendor_change=yes', '--allowerasing']
-    config_opts['dnf_install_command'] = 'install python3-dnf python3-dnf-plugins-core'
-    config_opts['dnf_disable_plugins'] = ['local', 'spacewalk', 'versionlock']
-    config_opts["dnf_avoid_opts"] = {}
+    config_opts['dnf4_command'] = '/usr/bin/dnf-3'
+    config_opts['dnf4_system_command'] = '/usr/bin/dnf-3'
+    config_opts['dnf4_common_opts'] = ['--setopt=deltarpm=False', '--setopt=allow_vendor_change=yes', '--allowerasing']
+    config_opts['dnf4_install_command'] = 'install python3-dnf python3-dnf-plugins-core'
+    config_opts['dnf4_disable_plugins'] = ['local', 'spacewalk', 'versionlock']
+    config_opts["dnf4_avoid_opts"] = {}
 
     config_opts['dnf5_command'] = '/usr/bin/dnf5'
-    config_opts['system_dnf5_command'] = '/usr/bin/dnf5'
+    config_opts['dnf5_system_command'] = '/usr/bin/dnf5'
     config_opts['dnf5_common_opts'] = ['--setopt=deltarpm=False', '--setopt=allow_vendor_change=yes', '--allowerasing']
     config_opts['dnf5_install_command'] = 'install dnf5 dnf5-plugins'
     config_opts['dnf5_disable_plugins'] = []

mock/py/mockbuild/package_manager.py

@@ -18,10 +18,11 @@
 from .mounts import BindMountPoint
 
 fallbacks = {
-    'dnf': ['dnf', 'dnf5', 'yum'],
-    'yum': ['yum', 'dnf', 'dnf5'],
-    'microdnf': ['microdnf', 'dnf','dnf5', 'yum'],
-    'dnf5': ['dnf5', 'dnf', 'yum'],
+    'dnf4': ['dnf4', 'dnf5', 'yum'],
+    'dnf': ['dnf4', 'dnf5', 'yum'],  # backward-compat
+    'yum': ['yum', 'dnf4', 'dnf5'],
+    'microdnf': ['microdnf', 'dnf4', 'dnf5', 'yum'],
+    'dnf5': ['dnf5', 'dnf4', 'yum'],
 }
 
 
@@ -30,7 +31,7 @@ def package_manager_from_string(name):
         return Dnf5
     if name == 'yum':
         return Yum
-    if name == 'dnf':
+    if name in ['dnf4', 'dnf']:  # dnf for backward compat
         return Dnf
     if name == 'microdnf':
         return MicroDnf
@@ -45,6 +46,9 @@ def package_manager_exists(pm_class, config_opts, chroot=None):
         return False
     # resolve symlinks, and detect that e.g. /bin/yum doesn't point to /bin/dnf
     real_pathname = os.path.realpath(pathname)
+    if name == 'dnf4':
+        # The DNF4 used to be /bin/dnf, not /bin/dnf4
+        name = 'dnf'
     return name in real_pathname
 
 
@@ -92,7 +96,7 @@ def package_manager_class_fallback(config_opts, buildroot, fallback):
 
             return pm_class
 
-    raise Exception("No package from {} found".format(fallbacks[desired]))
+    raise Exception(f"No package from {fallbacks[desired]} found, desired {desired}")
 
 
 def package_manager(buildroot, bootstrap_buildroot, fallback):
@@ -122,7 +126,7 @@ def get_command(cls, config):
         if config.get("use_bootstrap_image", True):
             return command
         if config.get("use_bootstrap", False):
-            sys_command = config.get(f"system_{cls.name}_command")
+            sys_command = config.get(f"{cls.name}_system_command")
             if sys_command:
                 return sys_command
         return command
@@ -671,7 +675,7 @@ def _check_missing(output):
 
 
 class Dnf(_PackageManager):
-    name = 'dnf'
+    name = 'dnf4'
     support_installroot = True
 
     def __init__(self, config, buildroot, plugins, bootstrap_buildroot):

releng/release-notes-next/dnf4-config-is-alias-to-dnf.feature

@@ -0,0 +1,21 @@
+Alias `dnf4` added for the `package_manager = dnf`.
+
+The options specific to DNF4, previously prefixed with `dnf_*`, have been
+renamed to `dnf4_*` too to avoid confusion with `dnf5_*` options.  For backward
+compatibility, the `dnf_*` prefixed variants still work, so these config pairs
+are equivalent:
+
+```python
+config_opts['dnf4_install_cmd'] = 'install python3-dnf python3-dnf-plugins-core'
+config_opts['dnf_install_cmd'] = 'install python3-dnf python3-dnf-plugins-core'
+
+config_opts['package_manager'] = 'dnf4'
+config_opts['package_manager'] = 'dnf'
+```
+
+Some of the `dnf_*` options remain unchanged because they are universal and used
+with DNF4, DNF5, or YUM, e.g., `dnf_vars`.
+
+While working on this rename, the rarely used `system_<PM>_command` options have
+been changed to `<PM>_system_command` to visually align with the rest of the
+package-manager-specific options. The old variants are still accepted.