Revert "Move `glob_to_regex` and `re_word_boundary` to `matrix-python-common` (#11505) (#11527)

This reverts commit a77c36989785c0d5565ab9a1169f4f88e512ce8a.

8 files changed, 124 insertions, 12 deletions

diff --git a/changelog.d/11527.misc b/changelog.d/11527.misc
new file mode 100644
index 0000000000..081eae317c
--- /dev/null
+++ b/changelog.d/11527.misc
@@ -0,0 +1 @@
+Temporarily revert usage of `matrix-python-common`.
diff --git a/synapse/config/room_directory.py b/synapse/config/room_directory.py
index 3c5e0f7ce7..57316c59b6 100644
--- a/synapse/config/room_directory.py
+++ b/synapse/config/room_directory.py
@@ -15,9 +15,8 @@
 
 from typing import List
 
-from matrix_common.regex import glob_to_regex
-
 from synapse.types import JsonDict
+from synapse.util import glob_to_regex
 
 from ._base import Config, ConfigError
 
diff --git a/synapse/config/tls.py b/synapse/config/tls.py
index 3e235b57a7..4ca111618f 100644
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@@ -16,12 +16,11 @@ import logging
 import os
 from typing import List, Optional, Pattern
 
-from matrix_common.regex import glob_to_regex
-
 from OpenSSL import SSL, crypto
 from twisted.internet._sslverify import Certificate, trustRootFromCertificates
 
 from synapse.config._base import Config, ConfigError
+from synapse.util import glob_to_regex
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 4697a62c18..8e37e76206 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -28,7 +28,6 @@ from typing import (
     Union,
 )
 
-from matrix_common.regex import glob_to_regex
 from prometheus_client import Counter, Gauge, Histogram
 
 from twisted.internet import defer
@@ -67,7 +66,7 @@ from synapse.replication.http.federation import (
 )
 from synapse.storage.databases.main.lock import Lock
 from synapse.types import JsonDict, get_domain_from_id
-from synapse.util import json_decoder, unwrapFirstError
+from synapse.util import glob_to_regex, json_decoder, unwrapFirstError
 from synapse.util.async_helpers import Linearizer, concurrently_execute
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.stringutils import parse_server_name
diff --git a/synapse/push/push_rule_evaluator.py b/synapse/push/push_rule_evaluator.py
index 659a53805d..7f68092ec5 100644
--- a/synapse/push/push_rule_evaluator.py
+++ b/synapse/push/push_rule_evaluator.py
@@ -17,10 +17,9 @@ import logging
 import re
 from typing import Any, Dict, List, Optional, Pattern, Tuple, Union
 
-from matrix_common.regex import glob_to_regex, to_word_pattern
-
 from synapse.events import EventBase
 from synapse.types import JsonDict, UserID
+from synapse.util import glob_to_regex, re_word_boundary
 from synapse.util.caches.lrucache import LruCache
 
 logger = logging.getLogger(__name__)
@@ -185,7 +184,7 @@ class PushRuleEvaluatorForEvent:
         r = regex_cache.get((display_name, False, True), None)
         if not r:
             r1 = re.escape(display_name)
-            r1 = to_word_pattern(r1)
+            r1 = re_word_boundary(r1)
             r = re.compile(r1, flags=re.IGNORECASE)
             regex_cache[(display_name, False, True)] = r
 
@@ -214,7 +213,7 @@ def _glob_matches(glob: str, value: str, word_boundary: bool = False) -> bool:
     try:
         r = regex_cache.get((glob, True, word_boundary), None)
         if not r:
-            r = glob_to_regex(glob, word_boundary=word_boundary)
+            r = glob_to_regex(glob, word_boundary)
             regex_cache[(glob, True, word_boundary)] = r
         return bool(r.search(value))
     except re.error:
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 386debd7db..7d26954244 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -87,7 +87,6 @@ REQUIREMENTS = [
     # with the latest security patches.
     "cryptography>=3.4.7",
     "ijson>=3.1",
-    "matrix-common==1.0.0",
 ]
 
 CONDITIONAL_REQUIREMENTS = {
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index f157132210..95f23e27b6 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -14,8 +14,9 @@
 
 import json
 import logging
+import re
 import typing
-from typing import Any, Callable, Dict, Generator, Optional
+from typing import Any, Callable, Dict, Generator, Optional, Pattern
 
 import attr
 from frozendict import frozendict
@@ -34,6 +35,9 @@ if typing.TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
+_WILDCARD_RUN = re.compile(r"([\?\*]+)")
+
+
 def _reject_invalid_json(val: Any) -> None:
     """Do not allow Infinity, -Infinity, or NaN values in JSON."""
     raise ValueError("Invalid JSON value: '%s'" % val)
@@ -181,3 +185,56 @@ def log_failure(
     if not consumeErrors:
         return failure
     return None
+
+
+def glob_to_regex(glob: str, word_boundary: bool = False) -> Pattern:
+    """Converts a glob to a compiled regex object.
+
+    Args:
+        glob: pattern to match
+        word_boundary: If True, the pattern will be allowed to match at word boundaries
+           anywhere in the string. Otherwise, the pattern is anchored at the start and
+           end of the string.
+
+    Returns:
+        compiled regex pattern
+    """
+
+    # Patterns with wildcards must be simplified to avoid performance cliffs
+    # - The glob `?**?**?` is equivalent to the glob `???*`
+    # - The glob `???*` is equivalent to the regex `.{3,}`
+    chunks = []
+    for chunk in _WILDCARD_RUN.split(glob):
+        # No wildcards? re.escape()
+        if not _WILDCARD_RUN.match(chunk):
+            chunks.append(re.escape(chunk))
+            continue
+
+        # Wildcards? Simplify.
+        qmarks = chunk.count("?")
+        if "*" in chunk:
+            chunks.append(".{%d,}" % qmarks)
+        else:
+            chunks.append(".{%d}" % qmarks)
+
+    res = "".join(chunks)
+
+    if word_boundary:
+        res = re_word_boundary(res)
+    else:
+        # \A anchors at start of string, \Z at end of string
+        res = r"\A" + res + r"\Z"
+
+    return re.compile(res, re.IGNORECASE)
+
+
+def re_word_boundary(r: str) -> str:
+    """
+    Adds word boundary characters to the start and end of an
+    expression to require that the match occur as a whole word,
+    but do so respecting the fact that strings starting or ending
+    with non-word characters will change word boundaries.
+    """
+    # we can't use \b as it chokes on unicode. however \W seems to be okay
+    # as shorthand for [^0-9A-Za-z_].
+    return r"(^|\W)%s(\W|$)" % (r,)
diff --git a/tests/util/test_glob_to_regex.py b/tests/util/test_glob_to_regex.py
new file mode 100644
index 0000000000..220accb92b
--- /dev/null
+++ b/tests/util/test_glob_to_regex.py
@@ -0,0 +1,59 @@
+# Copyright 2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from synapse.util import glob_to_regex
+
+from tests.unittest import TestCase
+
+
+class GlobToRegexTestCase(TestCase):
+    def test_literal_match(self):
+        """patterns without wildcards should match"""
+        pat = glob_to_regex("foobaz")
+        self.assertTrue(
+            pat.match("FoobaZ"), "patterns should match and be case-insensitive"
+        )
+        self.assertFalse(
+            pat.match("x foobaz"), "pattern should not match at word boundaries"
+        )
+
+    def test_wildcard_match(self):
+        pat = glob_to_regex("f?o*baz")
+
+        self.assertTrue(
+            pat.match("FoobarbaZ"),
+            "* should match string and pattern should be case-insensitive",
+        )
+        self.assertTrue(pat.match("foobaz"), "* should match 0 characters")
+        self.assertFalse(pat.match("fooxaz"), "the character after * must match")
+        self.assertFalse(pat.match("fobbaz"), "? should not match 0 characters")
+        self.assertFalse(pat.match("fiiobaz"), "? should not match 2 characters")
+
+    def test_multi_wildcard(self):
+        """patterns with multiple wildcards in a row should match"""
+        pat = glob_to_regex("**baz")
+        self.assertTrue(pat.match("agsgsbaz"), "** should match any string")
+        self.assertTrue(pat.match("baz"), "** should match the empty string")
+        self.assertEqual(pat.pattern, r"\A.{0,}baz\Z")
+
+        pat = glob_to_regex("*?baz")
+        self.assertTrue(pat.match("agsgsbaz"), "*? should match any string")
+        self.assertTrue(pat.match("abaz"), "*? should match a single char")
+        self.assertFalse(pat.match("baz"), "*? should not match the empty string")
+        self.assertEqual(pat.pattern, r"\A.{1,}baz\Z")
+
+        pat = glob_to_regex("a?*?*?baz")
+        self.assertTrue(pat.match("a g baz"), "?*?*? should match 3 chars")
+        self.assertFalse(pat.match("a..baz"), "?*?*? should not match 2 chars")
+        self.assertTrue(pat.match("a.gg.baz"), "?*?*? should match 4 chars")
+        self.assertEqual(pat.pattern, r"\Aa.{3,}baz\Z")