Hook can help debug regex usage

regexploit/hook.py

@@ -26,6 +26,41 @@ def last_tb(self):
         return self.traceback[-1]
 
 
+class WrappedRegex:
+    def __init__(self, regex):
+        self.regex = regex
+
+    def run_and_log(self, method, args, kwargs):
+        print("Pattern:", repr(self.regex.pattern[:200]))
+        print(f"{method}()", *(repr(a) for a in args))
+        print(*traceback.format_stack()[2:-4])
+        return getattr(self.regex, method)(*args, **kwargs)
+
+    def search(self, *args, **kwargs):
+        return self.run_and_log("search", args, kwargs)
+
+    def match(self, *args, **kwargs):
+        return self.run_and_log("match", args, kwargs)
+
+    def fullmatch(self, *args, **kwargs):
+        return self.run_and_log("fullmatch", args, kwargs)
+
+    def sub(self, *args, **kwargs):
+        return self.run_and_log("sub", args, kwargs)
+
+    def subn(self, *args, **kwargs):
+        return self.run_and_log("subn", args, kwargs)
+
+    def split(self, *args, **kwargs):
+        return self.run_and_log("split", args, kwargs)
+
+    def findall(self, *args, **kwargs):
+        return self.run_and_log("findall", args, kwargs)
+
+    def finditer(self, *args, **kwargs):
+        return self.run_and_log("finditer", args, kwargs)
+
+
 def get_and_clear_regexes():
     """
     Retrieves regexes that have been `re.compile`-ed and removes them from the `regexes` set.
@@ -37,7 +72,7 @@ def get_and_clear_regexes():
             return
 
 
-def install():
+def install(log_all_uses: bool = False):
     """
     Activate the hook.
     """
@@ -47,7 +82,11 @@ def install():
         def compile(pattern, flags=0):
             tb = traceback.extract_stack()[:-1]  # Ignore our hook
             regexes.add(CompiledRegex(pattern, flags, tb))
-            return old_compile(pattern, flags)
+            regex = old_compile(pattern, flags)
+            if log_all_uses:
+                return WrappedRegex(regex)
+            else:
+                return regex
 
         compile._is_hook = True
         re.compile = compile