From 80991af3a6a02a6cfd2a0f8f97d19951e3506935 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Mon, 4 May 2026 22:52:29 +0300
Subject: [PATCH] gh-149381: Optimize robotparser for long list of rules

---
 Lib/test/test_robotparser.py |  6 +++---
 Lib/urllib/robotparser.py    | 15 +++++++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_robotparser.py b/Lib/test/test_robotparser.py
index 3ea0ec66fbfbe9..2ce916fedc2708 100644
--- a/Lib/test/test_robotparser.py
+++ b/Lib/test/test_robotparser.py
@@ -388,8 +388,8 @@ class IgnoreEmptyLinesTest(BaseRobotTest, unittest.TestCase):
     expected_output = """\
 User-agent: spambot
 User-agent: eggsbot
-Disallow: /some/path
-Disallow: /another/path\
+Disallow: /another/path
+Disallow: /some/path\
 """
 
 
@@ -445,10 +445,10 @@ class WeirdPathTest(BaseRobotTest, unittest.TestCase):
            '/e$$', '/ex$y$', '/g']
     expected_output = """\
 User-agent: *
-Disallow: /a$
 Disallow: /c*
 Disallow: /d*z
 Disallow: /e*$
+Disallow: /a$
 Disallow: /g$\
 """
 
diff --git a/Lib/urllib/robotparser.py b/Lib/urllib/robotparser.py
index e70eae80036784..13e016ff74c2ee 100644
--- a/Lib/urllib/robotparser.py
+++ b/Lib/urllib/robotparser.py
@@ -81,6 +81,7 @@ def _add_entry(self, entry):
                 self.groups[agent] = entry
             else:
                 self.groups[agent] = merge_entries(self.groups[agent], entry)
+            sort_rulelines(self.groups[agent].rulelines)
 
     def parse(self, lines):
         """Parse the input lines from a robots.txt file.
@@ -305,6 +306,9 @@ def allowance(self, filename):
         """Preconditions:
         - our agent applies to this entry
         - filename is URL encoded
+        - rules are sorted:
+          - wildcards before literal paths
+          - literal paths from longest to shortest, "Allow" before "Disallow"
         """
         best_match = -1
         allowance = True
@@ -316,6 +320,9 @@ def allowance(self, filename):
                     allowance = line.allowance
                 elif m == best_match and not allowance:
                     allowance = line.allowance
+            # Optimization. Requires rules to be sorted.
+            if line.matcher is None and (m or len(line.path) + 1 < best_match):
+                break
         return allowance
 
 
@@ -353,3 +360,11 @@ def merge_entries(e1, e2):
     entry.delay = e1.delay if e2.delay is None else e2.delay
     entry.req_rate = e1.req_rate if e2.req_rate is None else e2.req_rate
     return entry
+
+def sort_rulelines(rulelines):
+    def sortkey(line):
+        if line.matcher is not None:
+            return (True,)
+        else:
+            return (False, len(line.path), line.allowance)
+    rulelines.sort(key=sortkey, reverse=True)