Fix the dnf -> dnf4 alias

mock/py/mockbuild/package_manager.py

@@ -19,26 +19,25 @@
 
 fallbacks = {
     'dnf4': ['dnf4', 'dnf5', 'yum'],
-    'dnf': ['dnf4', 'dnf5', 'yum'],  # backward-compat
     'yum': ['yum', 'dnf4', 'dnf5'],
     'microdnf': ['microdnf', 'dnf4', 'dnf5', 'yum'],
     'dnf5': ['dnf5', 'dnf4', 'yum'],
 }
 
 
-def package_manager_from_string(name):
+def _package_manager_from_string(name):
     if name == 'dnf5':
         return Dnf5
     if name == 'yum':
         return Yum
-    if name in ['dnf4', 'dnf']:  # dnf for backward compat
+    if name in 'dnf4':
         return Dnf
     if name == 'microdnf':
         return MicroDnf
-    raise Exception('Unrecognized package manager "{}"'.format(name))
+    raise RuntimeError(f'Unrecognized package manager "{name}"')
 
 
-def package_manager_exists(pm_class, config_opts, chroot=None):
+def _package_manager_exists(pm_class, config_opts, chroot=None):
     name = pm_class.name
     command = pm_class.get_command(config_opts)
     pathname = (chroot or "") + command
@@ -52,10 +51,14 @@ def package_manager_exists(pm_class, config_opts, chroot=None):
     return name in real_pathname
 
 
-def package_manager_class_fallback(config_opts, buildroot, fallback):
+def _package_manager_class_fallback(config_opts, buildroot, fallback):
     desired = config_opts['package_manager']
+
+    if desired == 'dnf':  # backward compat
+        desired = 'dnf4'
+
     if not fallback:
-        return package_manager_from_string(desired)
+        return _package_manager_from_string(desired)
 
     getLog().debug("searching for '%s' package manager or alternatives", desired)
     if desired not in fallbacks:
@@ -69,10 +72,8 @@ def package_manager_class_fallback(config_opts, buildroot, fallback):
     bootstrap = buildroot.is_bootstrap
 
     for manager in fallbacks[desired]:
-        pm_class = package_manager_from_string(manager)
-        package_manager_exists(pm_class, config_opts)
-
-        if package_manager_exists(pm_class, config_opts, chroot=chroot_to_search_in):
+        pm_class = _package_manager_from_string(manager)
+        if _package_manager_exists(pm_class, config_opts, chroot=chroot_to_search_in):
             if desired == manager:
                 return pm_class
 
@@ -83,6 +84,7 @@ def package_manager_class_fallback(config_opts, buildroot, fallback):
                 return pm_class
 
             if not bootstrap:
+                # pylint: disable=consider-using-f-string
                 print("""WARNING! WARNING! WARNING!
 You are building package for distribution which uses {0}. However your system
 does not support {0}. You can continue with {1}, which will likely succeed,
@@ -96,11 +98,11 @@ def package_manager_class_fallback(config_opts, buildroot, fallback):
 
             return pm_class
 
-    raise Exception(f"No package from {fallbacks[desired]} found, desired {desired}")
+    raise RuntimeError(f"No package from {fallbacks[desired]} found, desired {desired}")
 
 
 def package_manager(buildroot, bootstrap_buildroot, fallback):
-    cls = package_manager_class_fallback(buildroot.config, buildroot, fallback)
+    cls = _package_manager_class_fallback(buildroot.config, buildroot, fallback)
     return cls(buildroot.config, buildroot, buildroot.plugins,
                bootstrap_buildroot)
 

releng/release-notes-next/dnf-to-dnf4-fallback-fix.bugfix

@@ -0,0 +1,3 @@
+A fix for the DNF → DNF4 fallback has been applied.  Now Mock correctly selects
+DNF4, even when the `--no-bootstrap-chroot` command is used.  See
+[issue#1475][] for more info.