CT 2000 fix semver prerelease comparisons (#6838)

* Modify semver.py to not use packaging.version.parse

* Changie

(cherry picked from commit d9424cc)

.changes/unreleased/Fixes-20230201-154418.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Remove pin on packaging and stop using it for prerelease comparisons
+time: 2023-02-01T15:44:18.279158-05:00
+custom:
+  Author: gshank
+  Issue: "6834"

core/dbt/semver.py

@@ -1,10 +1,7 @@
 from dataclasses import dataclass
 import re
-import warnings
 from typing import List
 
-from packaging import version as packaging_version
-
 from dbt.exceptions import VersionsNotCompatibleError
 import dbt.utils
 
@@ -70,6 +67,11 @@ class VersionSpecification(dbtClassMixin):
 _VERSION_REGEX = re.compile(_VERSION_REGEX_PAT_STR, re.VERBOSE)
 
 
+def _cmp(a, b):
+    """Return negative if a<b, zero if a==b, positive if a>b."""
+    return (a > b) - (a < b)
+
+
 @dataclass
 class VersionSpecifier(VersionSpecification):
     def to_version_string(self, skip_matcher=False):
@@ -142,13 +144,19 @@ def compare(self, other):
                     return 1
                 if b is None:
                     return -1
-            # This suppresses the LegacyVersion deprecation warning
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", category=DeprecationWarning)
-                if packaging_version.parse(a) > packaging_version.parse(b):
+
+                # Check the prerelease component only
+                prcmp = self._nat_cmp(a, b)
+                if prcmp != 0:  # either -1 or 1
+                    return prcmp
+                # else is equal and will fall through
+
+            else:  # major/minor/patch, should all be numbers
+                if a > b:
                     return 1
-                elif packaging_version.parse(a) < packaging_version.parse(b):
+                elif a < b:
                     return -1
+                # else is equal and will fall through
 
         equal = (
             self.matcher == Matchers.GREATER_THAN_OR_EQUAL
@@ -212,6 +220,29 @@ def is_upper_bound(self):
     def is_exact(self):
         return self.matcher == Matchers.EXACT
 
+    @classmethod
+    def _nat_cmp(cls, a, b):
+        def cmp_prerelease_tag(a, b):
+            if isinstance(a, int) and isinstance(b, int):
+                return _cmp(a, b)
+            elif isinstance(a, int):
+                return -1
+            elif isinstance(b, int):
+                return 1
+            else:
+                return _cmp(a, b)
+
+        a, b = a or "", b or ""
+        a_parts, b_parts = a.split("."), b.split(".")
+        a_parts = [int(x) if re.match(r"^\d+$", x) else x for x in a_parts]
+        b_parts = [int(x) if re.match(r"^\d+$", x) else x for x in b_parts]
+        for sub_a, sub_b in zip(a_parts, b_parts):
+            cmp_result = cmp_prerelease_tag(sub_a, sub_b)
+            if cmp_result != 0:
+                return cmp_result
+        else:
+            return _cmp(len(a), len(b))
+
 
 @dataclass
 class VersionRange:

core/setup.py

@@ -58,7 +58,7 @@
         "minimal-snowplow-tracker==0.0.2",
         "networkx>=2.3,<2.8.1;python_version<'3.8'",
         "networkx>=2.3,<3;python_version>='3.8'",
-        "packaging>=20.9,<22.0",
+        "packaging>20.9",
         "sqlparse>=0.2.3,<0.5",
         "dbt-extractor~=0.4.1",
         "typing-extensions>=3.7.4",

test/unit/test_semver.py

@@ -201,12 +201,16 @@ def test__resolve_to_specific_version(self):
             '1.1.0')
 
     def test__filter_installable(self):
-        assert filter_installable(
+        installable = filter_installable(
             ['1.1.0',  '1.2.0a1', '1.0.0','2.1.0-alpha','2.2.0asdf','2.1.0','2.2.0','2.2.0-fishtown-beta','2.2.0-2'],
             install_prerelease=True
-        ) == ['1.0.0', '1.1.0', '1.2.0a1','2.1.0-alpha','2.1.0','2.2.0asdf','2.2.0-fishtown-beta','2.2.0-2','2.2.0']
+        )
+        expected = ['1.0.0', '1.1.0', '1.2.0a1','2.1.0-alpha','2.1.0','2.2.0-2','2.2.0asdf','2.2.0-fishtown-beta','2.2.0']
+        assert installable == expected
 
-        assert filter_installable(
+        installable = filter_installable(
             ['1.1.0',  '1.2.0a1', '1.0.0','2.1.0-alpha','2.2.0asdf','2.1.0','2.2.0','2.2.0-fishtown-beta'],
             install_prerelease=False
-        ) == ['1.0.0', '1.1.0','2.1.0','2.2.0']
+        )
+        expected = ['1.0.0', '1.1.0','2.1.0','2.2.0']
+        assert installable == expected