From a614ec8eeb440f2fd4bfb196ddb1d24406d420a6 Mon Sep 17 00:00:00 2001
From: Evan Goode <mail@evangoo.de>
Date: Mon, 18 Sep 2023 20:42:09 +0000
Subject: [PATCH 02/11] Split $releasever to $releasever_major and
 $releasever_minor

Whenever the `releasever` substitution variable is set, automatically
derive and set the `releasever_major` and `releasever_minor` vars by
splitting `releasever` on the first ".".

Companion to the DNF 5 implementation here: https://github.com/rpm-software-management/dnf5/pull/800

DNF 5 issue: https://github.com/rpm-software-management/dnf5/issues/710

For https://bugzilla.redhat.com/show_bug.cgi?id=1789346
---
 dnf/conf/substitutions.py        | 31 +++++++++++++++++++++++++++++++
 dnf/exceptions.py                |  6 ++++++
 tests/conf/test_substitutions.py | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 69 insertions(+)

diff --git a/dnf/conf/substitutions.py b/dnf/conf/substitutions.py
index 4d0f0d55e..5c736a8df 100644
--- a/dnf/conf/substitutions.py
+++ b/dnf/conf/substitutions.py
@@ -23,8 +23,10 @@ import os
 import re
 
 from dnf.i18n import _
+from dnf.exceptions import ReadOnlyVariableError
 
 ENVIRONMENT_VARS_RE = re.compile(r'^DNF_VAR_[A-Za-z0-9_]+$')
+READ_ONLY_VARIABLES = frozenset(("releasever_major", "releasever_minor"))
 logger = logging.getLogger('dnf')
 
 
@@ -43,6 +45,35 @@ class Substitutions(dict):
             elif key in numericvars:
                 self[key] = val
 
+    @staticmethod
+    def _split_releasever(releasever):
+        # type: (str) -> tuple[str, str]
+        pos = releasever.find(".")
+        if pos == -1:
+            releasever_major = releasever
+            releasever_minor = ""
+        else:
+            releasever_major = releasever[:pos]
+            releasever_minor = releasever[pos + 1:]
+        return releasever_major, releasever_minor
+
+    def __setitem__(self, key, value):
+        if Substitutions.is_read_only(key):
+            raise ReadOnlyVariableError(f"Variable \"{key}\" is read-only", variable_name=key)
+
+        setitem = super(Substitutions, self).__setitem__
+        setitem(key, value)
+
+        if key == "releasever" and value:
+            releasever_major, releasever_minor = Substitutions._split_releasever(value)
+            setitem("releasever_major", releasever_major)
+            setitem("releasever_minor", releasever_minor)
+
+    @staticmethod
+    def is_read_only(key):
+        # type: (str) -> bool
+        return key in READ_ONLY_VARIABLES
+
     def update_from_etc(self, installroot, varsdir=("/etc/yum/vars/", "/etc/dnf/vars/")):
         # :api
 
diff --git a/dnf/exceptions.py b/dnf/exceptions.py
index ef731781d..2d009b2ad 100644
--- a/dnf/exceptions.py
+++ b/dnf/exceptions.py
@@ -180,6 +180,12 @@ class ProcessLockError(LockError):
         return (ProcessLockError, (self.value, self.pid))
 
 
+class ReadOnlyVariableError(Error):
+    def __init__(self, value, variable_name):
+        super(ReadOnlyVariableError, self).__init__(value)
+        self.variable_name = variable_name
+
+
 class RepoError(Error):
     # :api
     pass
diff --git a/tests/conf/test_substitutions.py b/tests/conf/test_substitutions.py
index b64533ff6..d8ac3c207 100644
--- a/tests/conf/test_substitutions.py
+++ b/tests/conf/test_substitutions.py
@@ -23,6 +23,8 @@ from __future__ import unicode_literals
 import os
 
 import dnf.conf
+from dnf.conf.substitutions import Substitutions
+from dnf.exceptions import ReadOnlyVariableError
 
 import tests.support
 
@@ -52,3 +54,33 @@ class SubstitutionsFromEnvironmentTest(tests.support.TestCase):
             conf.substitutions.keys(),
             ['basearch', 'arch', 'GENRE', 'EMPTY'])
         self.assertEqual('opera', conf.substitutions['GENRE'])
+
+
+class SubstitutionsReadOnlyTest(tests.support.TestCase):
+    def test_set_readonly(self):
+        conf = dnf.conf.Conf()
+        variable_name = "releasever_major"
+        self.assertTrue(Substitutions.is_read_only(variable_name))
+        with self.assertRaises(ReadOnlyVariableError) as cm:
+            conf.substitutions["releasever_major"] = "1"
+        self.assertEqual(cm.exception.variable_name, "releasever_major")
+
+
+class SubstitutionsReleaseverTest(tests.support.TestCase):
+    def test_releasever_simple(self):
+        conf = dnf.conf.Conf()
+        conf.substitutions["releasever"] = "1.23"
+        self.assertEqual(conf.substitutions["releasever_major"], "1")
+        self.assertEqual(conf.substitutions["releasever_minor"], "23")
+
+    def test_releasever_major_only(self):
+        conf = dnf.conf.Conf()
+        conf.substitutions["releasever"] = "123"
+        self.assertEqual(conf.substitutions["releasever_major"], "123")
+        self.assertEqual(conf.substitutions["releasever_minor"], "")
+
+    def test_releasever_multipart(self):
+        conf = dnf.conf.Conf()
+        conf.substitutions["releasever"] = "1.23.45"
+        self.assertEqual(conf.substitutions["releasever_major"], "1")
+        self.assertEqual(conf.substitutions["releasever_minor"], "23.45")
-- 
2.49.0