From 4aae0bcc2cd82e06572718b4db6eba5bc47a9e1c Mon Sep 17 00:00:00 2001
From: Philipp Wolfer <ph.wolfer@gmail.com>
Date: Mon, 31 May 2021 23:05:17 +0200
Subject: [PATCH] PICARD-2218: Allow regular expressions in $performer(pattern)

---
 picard/script/functions.py |  8 +++++++-
 test/test_script.py        | 15 ++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/picard/script/functions.py b/picard/script/functions.py
index 7e9d97d90..10333db48 100644
--- a/picard/script/functions.py
+++ b/picard/script/functions.py
@@ -761,6 +761,7 @@ def func_lenmulti(parser, multi, separator=MULTI_VALUED_JOINER):
     """`$performer(pattern="",join=", ")`
 
 Returns the performers where the performance type (e.g. "vocal") matches `pattern`, joined by `join`.
+`pattern` can be a regular expression.
 
 _Since Picard 0.10_"""
 ))
@@ -769,7 +770,12 @@ def func_performer(parser, pattern="", join=", "):
     for name, value in parser.context.items():
         if name.startswith("performer:"):
             name, performance = name.split(':', 2)
-            if pattern in performance:
+            try:
+                match = bool(re.search(pattern, performance))
+            except re.error:
+                # fall back to simple string matching if regex is invalid
+                match = pattern in performance
+            if match:
                 values.append(value)
     return join.join(values)
 
diff --git a/test/test_script.py b/test/test_script.py
index 4373696d8..8a3ac48da 100644
--- a/test/test_script.py
+++ b/test/test_script.py
@@ -3,7 +3,7 @@
 # Picard, the next-generation MusicBrainz tagger
 #
 # Copyright (C) 2007 Lukáš Lalinský
-# Copyright (C) 2010, 2014, 2018-2020 Philipp Wolfer
+# Copyright (C) 2010, 2014, 2018-2021 Philipp Wolfer
 # Copyright (C) 2012 Chad Wilson
 # Copyright (C) 2013 Michael Wiencek
 # Copyright (C) 2013, 2017-2020 Laurent Monin
@@ -942,6 +942,19 @@ class ScriptParserTest(PicardTestCase):
         self.assertEqual({'Foo1', 'Foo2', 'Foo3', 'Drummer'}, set(result.split(', ')))
         self.assertScriptResultEquals("$performer(perf)", "", context)
 
+    def test_cmd_performer_regex(self):
+        context = Metadata()
+        context['performer:guitar'] = 'Foo1'
+        context['performer:guitars'] = 'Foo2'
+        context['performer:rhythm-guitar'] = 'Foo3'
+        context['performer:drums (drum kit)'] = 'Drummer'
+        result = self.parser.eval(r"$performer(^guitar)", context=context)
+        self.assertEqual({'Foo1', 'Foo2'}, set(result.split(', ')))
+        result = self.parser.eval(r"$performer(^guitar\$)", context=context)
+        self.assertEqual({'Foo1'}, set(result.split(', ')))
+        result = self.parser.eval(r"$performer(drums \()", context=context)
+        self.assertEqual({'Drummer'}, set(result.split(', ')))
+
     def test_cmd_performer_custom_join(self):
         context = Metadata()
         context['performer:guitar'] = 'Foo1'