From 18f0ca68e3c71178a2266e8fb92905bb5a399633 Mon Sep 17 00:00:00 2001
From: Will Thompson <will@willthompson.co.uk>
Date: Fri, 3 May 2024 13:31:26 +0100
Subject: [PATCH 1/2] htmlchecker: Move _get_pattern() helper to Checker class

This will be used to replace some very similar code in gitchecker.
---
 src/checkers/__init__.py    | 23 +++++++++++++++++++++++
 src/checkers/htmlchecker.py | 27 +++++----------------------
 2 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/src/checkers/__init__.py b/src/checkers/__init__.py
index 5dccdc42..fb5cd687 100644
--- a/src/checkers/__init__.py
+++ b/src/checkers/__init__.py
@@ -180,6 +180,29 @@ def _substitute_template(
         except (KeyError, ValueError) as err:
             raise CheckerMetadataError("Error substituting template") from err
 
+    @classmethod
+    def _get_pattern(
+        cls,
+        checker_data: t.Dict,
+        pattern_name: str,
+        expected_groups: int = 1,
+    ) -> t.Optional[re.Pattern]:
+        try:
+            pattern_str = checker_data[pattern_name]
+        except KeyError:
+            return None
+
+        try:
+            pattern = re.compile(pattern_str)
+        except re.error as err:
+            raise CheckerMetadataError(f"Invalid regex '{pattern_str}'") from err
+        if pattern.groups != expected_groups:
+            raise CheckerMetadataError(
+                f"Pattern '{pattern.pattern}' contains {pattern.groups} group(s) "
+                f"instead of {expected_groups}"
+            )
+        return pattern
+
     async def _complete_digests(
         self, url: t.Union[str, URL], digests: MultiDigest
     ) -> MultiDigest:
diff --git a/src/checkers/htmlchecker.py b/src/checkers/htmlchecker.py
index b953948a..1c2a140e 100644
--- a/src/checkers/htmlchecker.py
+++ b/src/checkers/htmlchecker.py
@@ -31,32 +31,13 @@
 
 from ..lib import NETWORK_ERRORS, OPERATORS_SCHEMA
 from ..lib.externaldata import ExternalBase, ExternalData
-from ..lib.errors import CheckerMetadataError, CheckerQueryError, CheckerFetchError
+from ..lib.errors import CheckerQueryError, CheckerFetchError
 from . import Checker
 from ..lib.utils import filter_versioned_items, FallbackVersion
 
 log = logging.getLogger(__name__)
 
 
-def _get_pattern(
-    checker_data: t.Dict, pattern_name: str, expected_groups: int = 1
-) -> t.Optional[re.Pattern]:
-    try:
-        pattern_str = checker_data[pattern_name]
-    except KeyError:
-        return None
-    try:
-        pattern = re.compile(pattern_str)
-    except re.error as err:
-        raise CheckerMetadataError(f"Invalid regex '{pattern_str}'") from err
-    if pattern.groups != expected_groups:
-        raise CheckerMetadataError(
-            f"Pattern '{pattern.pattern}' contains {pattern.groups} group(s) "
-            f"instead of {expected_groups}"
-        )
-    return pattern
-
-
 def _semantic_version(version: str) -> semver.VersionInfo:
     try:
         return semver.VersionInfo.parse(version)
@@ -157,8 +138,10 @@ async def check(self, external_data: ExternalBase):
             {f"parent_{k}": v for k, v in parent_json.items() if v is not None},
         )
 
-        combo_pattern = _get_pattern(external_data.checker_data, "pattern", 2)
-        version_pattern = _get_pattern(external_data.checker_data, "version-pattern", 1)
+        combo_pattern = self._get_pattern(external_data.checker_data, "pattern", 2)
+        version_pattern = self._get_pattern(
+            external_data.checker_data, "version-pattern", 1
+        )
         url_template = external_data.checker_data.get("url-template")
         sort_matches = external_data.checker_data.get("sort-matches", True)
         version_cls = _VERSION_SCHEMES[

From 1a0e0c76449a20344584644cca69c6c61d494af2 Mon Sep 17 00:00:00 2001
From: Will Thompson <will@willthompson.co.uk>
Date: Fri, 3 May 2024 13:32:35 +0100
Subject: [PATCH 2/2] gitchecker: Use Checker._get_pattern helper

Rather than asserting when given the wrong number of match
groups, this helper raises a descriptive exception. This is both more
helpful to the developer who has incorrectly specified the tag-pattern,
but also seems to prevent an issue where an assertion failure causes the
asyncio mainloop to hang.

Fixes #418

Thanks to Tobias Micheler <tobiasmicheler@outlook.de> for finding the
issue!
---
 src/checkers/gitchecker.py | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/checkers/gitchecker.py b/src/checkers/gitchecker.py
index 35f04c9a..4a620515 100644
--- a/src/checkers/gitchecker.py
+++ b/src/checkers/gitchecker.py
@@ -92,13 +92,11 @@ async def check(self, external_data: ExternalBase):
             return await self._check_has_new(external_data)
         return await self._check_still_valid(external_data)
 
-    @staticmethod
-    async def _check_has_new(external_data: ExternalGitRepo):
-        tag_pattern = external_data.checker_data.get(
-            "tag-pattern", r"^(?:[vV])?((?:\d+\.)+\d+)$"
-        )
-        tag_re = re.compile(tag_pattern)
-        assert tag_re.groups == 1
+    @classmethod
+    async def _check_has_new(cls, external_data: ExternalGitRepo):
+        tag_re = cls._get_pattern(external_data.checker_data, "tag-pattern", 1)
+        if tag_re is None:
+            tag_re = re.compile(r"^(?:[vV])?((?:\d+\.)+\d+)$")
 
         version_scheme = external_data.checker_data.get("version-scheme", "loose")
         tag_cls = TAG_VERSION_SCHEMES[version_scheme]
@@ -142,7 +140,7 @@ async def _check_has_new(external_data: ExternalGitRepo):
         except IndexError as err:
             raise CheckerQueryError(
                 f"{external_data.current_version.url} has no tags matching "
-                f"'{tag_pattern}'"
+                f"'{tag_re.pattern}'"
             ) from err
 
         new_version = ExternalGitRef(