From 47ec0c67ca07efe718f9a4940f3301020dbf1bf0 Mon Sep 17 00:00:00 2001
From: Lance Edgar <lance@wuttaproject.org>
Date: Sat, 6 Sep 2025 16:29:11 -0500
Subject: [PATCH] fix: add `apt.is_installed()` function

---
 rattail_fabric2/apt.py | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/rattail_fabric2/apt.py b/rattail_fabric2/apt.py
index e685c5a..1dd8014 100644
--- a/rattail_fabric2/apt.py
+++ b/rattail_fabric2/apt.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2018 Lance Edgar
+#  Copyright © 2010-2025 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -44,6 +44,19 @@ def install(c, *packages, **kwargs):
         frontend, target, force_yes, ' '.join(packages)), **kwargs)
 
 
+def is_installed(c, package):
+    """
+    Check if the given APT package is installed.
+
+    :param c: Fabric connection.
+
+    :param package: Name of package to be checked.
+
+    :returns: ``True`` if package is installed, else ``False``.
+    """
+    return c.run(f"dpkg-query -s {package}", warn=True).ok
+
+
 def purge(c, *packages):
     """
     Uninstall and purge config for given packages