From e9d20387c1b4f9efea263e1f24b442b4bd3ae5d1 Mon Sep 17 00:00:00 2001
From: Lubomír Sedlář <lsedlar@redhat.com>
Date: Jan 13 2021 09:23:50 +0000
Subject: [PATCH 1/2] Add python 3.9 to tox configuration


---

diff --git a/tox.ini b/tox.ini
index b965783..00f86a1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist=py27,py35,py36,py37,py38,coverage
+envlist=py27,py35,py36,py37,py38,py39,coverage
 skip_missing_interpreters = true
 minversion=3.12.0
 

From 6bed097706a77b960edc3d89497211df518d40df Mon Sep 17 00:00:00 2001
From: Lubomír Sedlář <lsedlar@redhat.com>
Date: Jan 13 2021 09:23:50 +0000
Subject: [PATCH 2/2] find_latest: Fix computation of previous version


If the version ends with .0, decrement the part before that.

JIRA: RHELCMP-3632

---

diff --git a/compose_utils/find_latest.py b/compose_utils/find_latest.py
index d64215b..2a89713 100644
--- a/compose_utils/find_latest.py
+++ b/compose_utils/find_latest.py
@@ -106,11 +106,37 @@ def filter_compatible_composes(composes, compose):
     )
 
 
+def get_previous_version(version):
+    """Determine previous version from the given one. The major version is
+    never decremented though.
+
+    >>> get_previous_version("1.2")
+    "1.1"
+    >>> get_previous_version("1.2.1")
+    "1.2.0"
+    >>> get_previous_version("1.2.0")
+    1.1.0
+    >>> get_previous_version("1.0")
+    ValueError
+    """
+    version_split = version.split(".")
+    pos = len(version_split) - 1
+    while pos > 1 and version_split[pos] == "0":
+        pos -= 1
+    if pos <= 1 and version_split[pos] == "0":
+        # The only non-zero position was actually the major version. We don't
+        # want to decrement that.
+        raise ValueError("No previous version for this major version.")
+    version_split[pos] = str(int(version_split[pos]) - 1)
+    return ".".join(version_split)
+
+
 def filter_previous_release(composes, compose):
     """Return composes for the previous product release"""
-    version_split = compose.info.release.version.split(".")
-    version_split[-1] = str(int(version_split[-1]) - 1)
-    previous_version = ".".join(version_split)
+    try:
+        previous_version = get_previous_version(compose.info.release.version)
+    except ValueError:
+        return []
     return filter_composes(
         composes,
         release_short=compose.info.release.short,
diff --git a/tests/test_find_latest.py b/tests/test_find_latest.py
index 033ceda..048a966 100644
--- a/tests/test_find_latest.py
+++ b/tests/test_find_latest.py
@@ -421,3 +421,18 @@ class TestGetRelatedComposes(unittest.TestCase):
         self.assertEqual(gpm.call_args_list, [mock.call(self.ci_list, self.ci)])
         self.assertEqual(gsmpv.call_args_list, [mock.call(self.ci_list, self.ci)])
         self.assertEqual(gsmpr.call_args_list, [mock.call(self.ci_list, self.ci)])
+
+
+class TestGetPreviousVersion(unittest.TestCase):
+    def test_two_digit(self):
+        self.assertEqual(find_latest.get_previous_version("7.9"), "7.8")
+
+    def test_three_digit(self):
+        self.assertEqual(find_latest.get_previous_version("1.2.3"), "1.2.2")
+
+    def test_end_with_zero_three_components(self):
+        self.assertEqual(find_latest.get_previous_version("1.2.0"), "1.1.0")
+
+    def test_end_with_zero_two_components(self):
+        with self.assertRaises(ValueError):
+            print(find_latest.get_previous_version("1.0"))