From 9f3328781b1c6b8ea26645098328f2c8404465ab Mon Sep 17 00:00:00 2001
From: Dan Helfman <witten@torsion.org>
Date: Wed, 6 Sep 2023 23:13:40 -0700
Subject: [PATCH] When "archive_name_format" is not set, filter archives using
 the default archive name format (#753).

---
 NEWS                          |  2 ++
 borgmatic/borg/create.py      |  5 +----
 borgmatic/borg/flags.py       | 16 +++++++++-------
 tests/unit/borg/test_flags.py | 11 ++++++++---
 4 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/NEWS b/NEWS
index b52cfeae..3c89e467 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,8 @@
  * #743: Add a monitoring hook for sending backup status and logs to to Grafana Loki. See the
    documentation for more information:
    https://torsion.org/borgmatic/docs/how-to/monitor-your-backups/#loki-hook
+ * #753: When "archive_name_format" is not set, filter archives using the default archive name
+   format.
  * Update documentation to recommend installing/upgrading borgmatic with pipx instead of pip. See the
    documentation for more information:
    https://torsion.org/borgmatic/docs/how-to/set-up-backups/#installation
diff --git a/borgmatic/borg/create.py b/borgmatic/borg/create.py
index cb61d0ee..b09eac8f 100644
--- a/borgmatic/borg/create.py
+++ b/borgmatic/borg/create.py
@@ -215,9 +215,6 @@ def make_list_filter_flags(local_borg_version, dry_run):
         return f'{base_flags}-'
 
 
-DEFAULT_ARCHIVE_NAME_FORMAT = '{hostname}-{now:%Y-%m-%dT%H:%M:%S.%f}'  # noqa: FS003
-
-
 def collect_borgmatic_source_directories(borgmatic_source_directory):
     '''
     Return a list of borgmatic-specific source directories used for state like database backups.
@@ -388,7 +385,7 @@ def create_archive(
     lock_wait = config.get('lock_wait', None)
     list_filter_flags = make_list_filter_flags(local_borg_version, dry_run)
     files_cache = config.get('files_cache')
-    archive_name_format = config.get('archive_name_format', DEFAULT_ARCHIVE_NAME_FORMAT)
+    archive_name_format = config.get('archive_name_format', flags.DEFAULT_ARCHIVE_NAME_FORMAT)
     extra_borg_options = config.get('extra_borg_options', {}).get('create', '')
 
     if feature.available(feature.Feature.ATIME, local_borg_version):
diff --git a/borgmatic/borg/flags.py b/borgmatic/borg/flags.py
index dc7e84d6..bcfadfa4 100644
--- a/borgmatic/borg/flags.py
+++ b/borgmatic/borg/flags.py
@@ -59,12 +59,15 @@ def make_repository_archive_flags(repository_path, archive, local_borg_version):
     )
 
 
+DEFAULT_ARCHIVE_NAME_FORMAT = '{hostname}-{now:%Y-%m-%dT%H:%M:%S.%f}'  # noqa: FS003
+
+
 def make_match_archives_flags(match_archives, archive_name_format, local_borg_version):
     '''
     Return match archives flags based on the given match archives value, if any. If it isn't set,
-    return match archives flags to match archives created with the given archive name format, if
-    any. This is done by replacing certain archive name format placeholders for ephemeral data (like
-    "{now}") with globs.
+    return match archives flags to match archives created with the given (or default) archive name
+    format. This is done by replacing certain archive name format placeholders for ephemeral data
+    (like "{now}") with globs.
     '''
     if match_archives:
         if feature.available(feature.Feature.MATCH_ARCHIVES, local_borg_version):
@@ -72,10 +75,9 @@ def make_match_archives_flags(match_archives, archive_name_format, local_borg_ve
         else:
             return ('--glob-archives', re.sub(r'^sh:', '', match_archives))
 
-    if not archive_name_format:
-        return ()
-
-    derived_match_archives = re.sub(r'\{(now|utcnow|pid)([:%\w\.-]*)\}', '*', archive_name_format)
+    derived_match_archives = re.sub(
+        r'\{(now|utcnow|pid)([:%\w\.-]*)\}', '*', archive_name_format or DEFAULT_ARCHIVE_NAME_FORMAT
+    )
 
     if derived_match_archives == '*':
         return ()
diff --git a/tests/unit/borg/test_flags.py b/tests/unit/borg/test_flags.py
index 804dd8f1..ba6cf2ea 100644
--- a/tests/unit/borg/test_flags.py
+++ b/tests/unit/borg/test_flags.py
@@ -88,8 +88,8 @@ def test_make_repository_archive_flags_with_borg_features_joins_repository_and_a
 @pytest.mark.parametrize(
     'match_archives,archive_name_format,feature_available,expected_result',
     (
-        (None, None, True, ()),
-        (None, '', True, ()),
+        (None, None, True, ('--match-archives', 'sh:{hostname}-*')),  # noqa: FS003
+        (None, '', True, ('--match-archives', 'sh:{hostname}-*')),  # noqa: FS003
         (
             're:foo-.*',
             '{hostname}-{now}',  # noqa: FS003
@@ -145,7 +145,12 @@ def test_make_repository_archive_flags_with_borg_features_joins_repository_and_a
             True,
             (),
         ),
-        (None, '{utcnow}-docs-{user}', False, ('--glob-archives', '*-docs-{user}')),  # noqa: FS003
+        (
+            None,
+            '{utcnow}-docs-{user}',  # noqa: FS003
+            False,
+            ('--glob-archives', '*-docs-{user}'),  # noqa: FS003
+        ),
     ),
 )
 def test_make_match_archives_flags_makes_flags_with_globs(