1 files changed, 39 insertions, 0 deletions
diff --git a/gitlint-core/gitlint/deprecation.py b/gitlint-core/gitlint/deprecation.py
new file mode 100644
index 0000000..b7c2f42
--- /dev/null
+++ b/gitlint-core/gitlint/deprecation.py
@@ -0,0 +1,39 @@
+import logging
+
+LOG = logging.getLogger("gitlint.deprecated")
+DEPRECATED_LOG_FORMAT = "%(levelname)s: %(message)s"
+
+
+class Deprecation:
+    """Singleton class that handles deprecation warnings and behavior."""
+
+    # LintConfig class that is used to determine deprecation behavior
+    config = None
+
+    # Set of warning messages that have already been logged, to prevent duplicate warnings
+    warning_msgs = set()
+
+    @classmethod
+    def get_regex_method(cls, rule, regex_option):
+        """Returns the regex method to be used for a given rule based on general.regex-style-search option.
+        Logs a warning if the deprecated re.match method is returned."""
+
+        # if general.regex-style-search is set, just return re.search
+        if cls.config.regex_style_search:
+            return regex_option.value.search
+
+        warning_msg = (
+            f"{rule.id} - {rule.name}: gitlint will be switching from using Python regex 'match' (match beginning) to "
+            "'search' (match anywhere) semantics. "
+            f"Please review your {rule.name}.regex option accordingly. "
+            "To remove this warning, set general.regex-style-search=True. "
+            "More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search"
+        )
+
+        # Only log warnings once
+        if warning_msg not in cls.warning_msgs:
+            log = logging.getLogger("gitlint.deprecated.regex_style_search")
+            log.warning(warning_msg)
+        cls.warning_msgs.add(warning_msg)
+
+        return regex_option.value.match