Index: hooks/scripts/extract_pr_numbers.py
===================================================================
--- /dev/null
+++ hooks/scripts/extract_pr_numbers.py
@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+
+##
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2019 Eric van Gyzen
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $FreeBSD$
+
+# Given a Subversion commit log on stdin, extract the PR numbers
+# and print them on a single line to stdout.
+#
+# The recommended form is:
+#
+# PR:   https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=123456
+#
+# Bare PR numbers are also accepted, multiple per line, with optional commas.
+# A commit log can have multiple "PR:" lines.
+# Specifically, any whitespace-delimited field that is entirely numeric
+# (with an optional trailing comma) is considered a PR number.
+# Other text is ignored.  See tests/test_extract_pr_numbers.py for examples.
+
+from __future__ import print_function
+import sys
+
+BZ_URL = 'https://bugs.freebsd.org/bugzilla/show_bug.cgi?id='
+prs = set()
+
+for line in sys.stdin:
+	if line[:3].upper() != 'PR:':
+		continue
+	fields = line[3:].split()
+	for field in fields:
+		if field.startswith(BZ_URL):
+			field = field[len(BZ_URL):]
+		field = field.rstrip(',')
+		try:
+			pr = int(field)
+		except ValueError as e:
+			continue
+		if pr <= 0:
+			continue
+		prs.add(pr)
+
+if prs:
+	print(' '.join(map(str, sorted(prs))))
Index: hooks/scripts/notify_bz.sh
===================================================================
--- hooks/scripts/notify_bz.sh
+++ hooks/scripts/notify_bz.sh
@@ -14,7 +14,7 @@
   exit 1
 fi
 
-PRS="$(svnlook info "$REPO" -r "$REV" | grep -e '^[[:space:]]*[pP][rR]:[[:space:]]*'|grep -Eo '([a-zA-Z]+\/)*[^[]([0-9]+)[^],]'|sed -Ee 's,[[:space:]],,g' -e 's,[a-zA-Z]+\/,,g')"
+PRS="$(svnlook info "$REPO" -r "$REV" | extract_pr_numbers.py)"
 
 if [ -z "$PRS" ]; then
   exit 0
Index: hooks/scripts/tests/test_extract_pr_numbers.py
===================================================================
--- /dev/null
+++ hooks/scripts/tests/test_extract_pr_numbers.py
@@ -0,0 +1,83 @@
+#!/usr/bin/env python
+
+##
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2019 Eric van Gyzen
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $FreeBSD$
+
+from __future__ import print_function
+import subprocess
+
+CASE_DATA = """
+123456|PR:	https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=123456
+123456|PR:	123456
+123456|pr:	123456
+123456|Pr:	123456
+123456|pR:	123456
+123456|PR:	123456 (foo bar)
+123456|PR:	123456 sort-of, but not really
+123456|PR:	123456 [exp-run]
+123456|PR:	123456 [1]
+123456|PR:123456 [1]
+123456|PR: 123456
+123456 234567|PR:	123456 234567 ...
+123456 234567|PR:	123456, 234567, ...
+123456 234567|PR:	123456 [1], 234567 [2], ...
+123456 234567|PR:	123456 and maybe 234567 but I doubt it...
+123456 234567|PR:123456 234567 ...
+123456 234567|PR: 123456 234567 ...
+123456 234567|Pr: 123456 234567 ...
+123456 234567|pR: 123456 234567 ...
+|PR 76812 is not a PR line because it has no ":"
+"""
+
+MULTI_LINE_CASE_DATA = [
+    '123456 234567|PR:\t123456\nPR:\t234567',
+    '123456 234567|' + \
+        'PR:\thttps://bugs.freebsd.org/bugzilla/show_bug.cgi?id=123456\n' + \
+        'PR:\thttps://bugs.freebsd.org/bugzilla/show_bug.cgi?id=234567\n',
+]
+
+for line in CASE_DATA.split('\n') + MULTI_LINE_CASE_DATA:
+	if not line: continue
+	(expected, case) = line.split('|', 1)
+        if expected != '':
+            expected += '\n'
+        proc = subprocess.Popen(
+		['../extract_pr_numbers.py'],
+		stdin=subprocess.PIPE,
+		stdout=subprocess.PIPE,
+		stderr=subprocess.PIPE
+	)
+	(stdout, stderr) = proc.communicate(case)
+	if proc.returncode != 0 or stderr != '' or stdout != expected:
+		print('FAIL:')
+		print('input:  ' + case)
+		print('output: ' + stdout)
+		print('stderr: ' + stderr)
+		print('status: ' + str(proc.returncode))
+	else:
+		print('PASS')