sbuild::chroot: Add get_used_keys method

This splits out the used_keys functionality from set_keyfile.
This is so that the keys used may be queried separately from
keyfile loading.

36 files changed, 304 insertions, 156 deletions

diff --git a/sbuild/sbuild-chroot-block-device-base.cc b/sbuild/sbuild-chroot-block-device-base.cc
index be7e5ccc..d3c45723 100644
--- a/sbuild/sbuild-chroot-block-device-base.cc
+++ b/sbuild/sbuild-chroot-block-device-base.cc
@@ -106,6 +106,14 @@ chroot_block_device_base::get_details (chroot const& chroot,
 }
 
 void
+chroot_block_device_base::get_used_keys (string_list& used_keys) const
+{
+  chroot::get_used_keys(used_keys);
+
+  used_keys.push_back("device");
+}
+
+void
 chroot_block_device_base::get_keyfile (chroot const& chroot,
 				       keyfile&      keyfile) const
 {
@@ -117,13 +125,11 @@ chroot_block_device_base::get_keyfile (chroot const& chroot,
 
 void
 chroot_block_device_base::set_keyfile (chroot&        chroot,
-				       keyfile const& keyfile,
-				       string_list&   used_keys)
+				       keyfile const& keyfile)
 {
-  chroot::set_keyfile(chroot, keyfile, used_keys);
+  chroot::set_keyfile(chroot, keyfile);
 
   keyfile::get_object_value(*this, &chroot_block_device_base::set_device,
 			    keyfile, get_name(), "device",
 			    keyfile::PRIORITY_REQUIRED);
-  used_keys.push_back("device");
 }
diff --git a/sbuild/sbuild-chroot-block-device-base.h b/sbuild/sbuild-chroot-block-device-base.h
index 74642359..66221e05 100644
--- a/sbuild/sbuild-chroot-block-device-base.h
+++ b/sbuild/sbuild-chroot-block-device-base.h
@@ -84,13 +84,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile& keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
     /// The block device to use.
     std::string device;
diff --git a/sbuild/sbuild-chroot-block-device.cc b/sbuild/sbuild-chroot-block-device.cc
index cb0ceba6..94cdece5 100644
--- a/sbuild/sbuild-chroot-block-device.cc
+++ b/sbuild/sbuild-chroot-block-device.cc
@@ -208,6 +208,12 @@ chroot_block_device::get_details (chroot const& chroot,
 }
 
 void
+chroot_block_device::get_used_keys (string_list& used_keys) const
+{
+  chroot_block_device_base::get_used_keys(used_keys);
+}
+
+void
 chroot_block_device::get_keyfile (chroot const& chroot,
 				  keyfile&      keyfile) const
 {
@@ -216,8 +222,7 @@ chroot_block_device::get_keyfile (chroot const& chroot,
 
 void
 chroot_block_device::set_keyfile (chroot&        chroot,
-				  keyfile const& keyfile,
-				  string_list&   used_keys)
+				  keyfile const& keyfile)
 {
-  chroot_block_device_base::set_keyfile(chroot, keyfile, used_keys);
+  chroot_block_device_base::set_keyfile(chroot, keyfile);
 }
diff --git a/sbuild/sbuild-chroot-block-device.h b/sbuild/sbuild-chroot-block-device.h
index 45316ae3..edafa6f2 100644
--- a/sbuild/sbuild-chroot-block-device.h
+++ b/sbuild/sbuild-chroot-block-device.h
@@ -92,13 +92,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
   };
 
 }
diff --git a/sbuild/sbuild-chroot-btrfs-snapshot.cc b/sbuild/sbuild-chroot-btrfs-snapshot.cc
index 55c77bb6..d18c156b 100644
--- a/sbuild/sbuild-chroot-btrfs-snapshot.cc
+++ b/sbuild/sbuild-chroot-btrfs-snapshot.cc
@@ -202,6 +202,16 @@ chroot_btrfs_snapshot::get_details (chroot const& chroot,
 }
 
 void
+chroot_btrfs_snapshot::get_used_keys (string_list& used_keys) const
+{
+  chroot::get_used_keys(used_keys);
+
+  used_keys.push_back("btrfs-source-subvolume");
+  used_keys.push_back("btrfs-snapshot-directory");
+  used_keys.push_back("btrfs-snapshot-name");
+}
+
+void
 chroot_btrfs_snapshot::get_keyfile (chroot const& chroot,
 				    keyfile& keyfile) const
 {
@@ -230,10 +240,9 @@ chroot_btrfs_snapshot::get_keyfile (chroot const& chroot,
 
 void
 chroot_btrfs_snapshot::set_keyfile (chroot&        chroot,
-				    keyfile const& keyfile,
-				    string_list&   used_keys)
+				    keyfile const& keyfile)
 {
-  chroot::set_keyfile(chroot, keyfile, used_keys);
+  chroot::set_keyfile(chroot, keyfile);
 
   bool session = static_cast<bool>(get_facet<chroot_facet_session>());
 
@@ -243,7 +252,6 @@ chroot_btrfs_snapshot::set_keyfile (chroot&        chroot,
 			    keyfile::PRIORITY_DISALLOWED :
 			    keyfile::PRIORITY_REQUIRED
 			    ); // Only needed for creating snapshot, not using snapshot
-  used_keys.push_back("btrfs-source-subvolume");
 
   keyfile::get_object_value(*this, &chroot_btrfs_snapshot::set_snapshot_directory,
 			    keyfile, get_name(), "btrfs-snapshot-directory",
@@ -251,12 +259,10 @@ chroot_btrfs_snapshot::set_keyfile (chroot&        chroot,
 			    keyfile::PRIORITY_DISALLOWED :
 			    keyfile::PRIORITY_REQUIRED
 			    ); // Only needed for creating snapshot, not using snapshot
-  used_keys.push_back("btrfs-snapshot-directory");
 
   keyfile::get_object_value(*this, &chroot_btrfs_snapshot::set_snapshot_name,
 			    keyfile, get_name(), "btrfs-snapshot-name",
 			    session ?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_DISALLOWED);
-  used_keys.push_back("btrfs-snapshot-name");
 }
diff --git a/sbuild/sbuild-chroot-btrfs-snapshot.h b/sbuild/sbuild-chroot-btrfs-snapshot.h
index b7d9488f..7354f2c2 100644
--- a/sbuild/sbuild-chroot-btrfs-snapshot.h
+++ b/sbuild/sbuild-chroot-btrfs-snapshot.h
@@ -132,13 +132,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile& keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// Btrfs source subvolume
diff --git a/sbuild/sbuild-chroot-custom.cc b/sbuild/sbuild-chroot-custom.cc
index 59163ddc..dcfc001a 100644
--- a/sbuild/sbuild-chroot-custom.cc
+++ b/sbuild/sbuild-chroot-custom.cc
@@ -177,6 +177,16 @@ chroot_custom::get_details (chroot const&  chroot,
 }
 
 void
+chroot_custom::get_used_keys (string_list& used_keys) const
+{
+  chroot::get_used_keys(used_keys);
+
+  used_keys.push_back("custom-cloneable");
+  used_keys.push_back("custom-purgeable");
+  used_keys.push_back("custom-source-cloneable");
+}
+
+void
 chroot_custom::get_keyfile (chroot const& chroot,
 			    keyfile&      keyfile) const
 {
@@ -190,10 +200,9 @@ chroot_custom::get_keyfile (chroot const& chroot,
 
 void
 chroot_custom::set_keyfile (chroot& chroot,
-			    keyfile const& keyfile,
-			    string_list&   used_keys)
+			    keyfile const& keyfile)
 {
-  chroot::set_keyfile(chroot, keyfile, used_keys);
+  chroot::set_keyfile(chroot, keyfile);
 
   bool session = static_cast<bool>(get_facet<chroot_facet_session>());
 
@@ -202,17 +211,14 @@ chroot_custom::set_keyfile (chroot& chroot,
 			    session ?
 			    keyfile::PRIORITY_DISALLOWED :
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("custom-cloneable");
 
   keyfile::get_object_value(*this, &chroot_custom::set_session_purgeable,
 			    keyfile, get_name(), "custom-session-purgeable",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("custom-purgeable");
 
   keyfile::get_object_value(*this, &chroot_custom::set_source_cloneable,
 			    keyfile, get_name(), "custom-source-cloneable",
 			    session ?
 			    keyfile::PRIORITY_DISALLOWED :
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("custom-source-cloneable");
 }
diff --git a/sbuild/sbuild-chroot-custom.h b/sbuild/sbuild-chroot-custom.h
index 2b46b0ce..e0b321d6 100644
--- a/sbuild/sbuild-chroot-custom.h
+++ b/sbuild/sbuild-chroot-custom.h
@@ -123,13 +123,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile& keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-                 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     bool purgeable;
diff --git a/sbuild/sbuild-chroot-directory-base.cc b/sbuild/sbuild-chroot-directory-base.cc
index 77bc7c8c..a0d9a66b 100644
--- a/sbuild/sbuild-chroot-directory-base.cc
+++ b/sbuild/sbuild-chroot-directory-base.cc
@@ -87,6 +87,15 @@ chroot_directory_base::get_details (chroot const& chroot,
 }
 
 void
+chroot_directory_base::get_used_keys (string_list& used_keys) const
+{
+  chroot::get_used_keys(used_keys);
+
+  used_keys.push_back("directory");
+  used_keys.push_back("location");
+}
+
+void
 chroot_directory_base::get_keyfile (chroot const& chroot,
 				    keyfile& keyfile) const
 {
@@ -98,10 +107,9 @@ chroot_directory_base::get_keyfile (chroot const& chroot,
 
 void
 chroot_directory_base::set_keyfile (chroot&        chroot,
-				    keyfile const& keyfile,
-				    string_list&   used_keys)
+				    keyfile const& keyfile)
 {
-  chroot::set_keyfile(chroot, keyfile, used_keys);
+  chroot::set_keyfile(chroot, keyfile);
 
   // "directory" should be required, but we also accept "location" as
   // an alternative (but deprecated) variant.  Therefore, ensure by
@@ -125,10 +133,8 @@ chroot_directory_base::set_keyfile (chroot&        chroot,
   keyfile::get_object_value(*this, &chroot_directory_base::set_directory,
 			    keyfile, get_name(), "directory",
 			    directory_priority);
-  used_keys.push_back("directory");
 
   keyfile::get_object_value(*this, &chroot_directory_base::set_directory,
 			    keyfile, get_name(), "location",
 			    location_priority);
-  used_keys.push_back("location");
 }
diff --git a/sbuild/sbuild-chroot-directory-base.h b/sbuild/sbuild-chroot-directory-base.h
index 29ce1d1e..7ec0b6a4 100644
--- a/sbuild/sbuild-chroot-directory-base.h
+++ b/sbuild/sbuild-chroot-directory-base.h
@@ -80,13 +80,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile& keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// The directory to use.
diff --git a/sbuild/sbuild-chroot-directory.cc b/sbuild/sbuild-chroot-directory.cc
index 613fd2c4..56bee0c6 100644
--- a/sbuild/sbuild-chroot-directory.cc
+++ b/sbuild/sbuild-chroot-directory.cc
@@ -152,6 +152,12 @@ chroot_directory::get_details (chroot const&  chroot,
 }
 
 void
+chroot_directory::get_used_keys (string_list& used_keys) const
+{
+  chroot_directory_base::get_used_keys(used_keys);
+}
+
+void
 chroot_directory::get_keyfile (chroot const& chroot,
 			       keyfile&      keyfile) const
 {
@@ -160,8 +166,7 @@ chroot_directory::get_keyfile (chroot const& chroot,
 
 void
 chroot_directory::set_keyfile (chroot& chroot,
-			       keyfile const& keyfile,
-			       string_list&   used_keys)
+			       keyfile const& keyfile)
 {
-  chroot_directory_base::set_keyfile(chroot, keyfile, used_keys);
+  chroot_directory_base::set_keyfile(chroot, keyfile);
 }
diff --git a/sbuild/sbuild-chroot-directory.h b/sbuild/sbuild-chroot-directory.h
index cae17e9e..5e7f9aa0 100644
--- a/sbuild/sbuild-chroot-directory.h
+++ b/sbuild/sbuild-chroot-directory.h
@@ -91,13 +91,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile& keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-                 string_list&   used_keys);
+		 keyfile const& keyfile);
   };
 
 }
diff --git a/sbuild/sbuild-chroot-facet-mountable.cc b/sbuild/sbuild-chroot-facet-mountable.cc
index ade3eb45..e39680c9 100644
--- a/sbuild/sbuild-chroot-facet-mountable.cc
+++ b/sbuild/sbuild-chroot-facet-mountable.cc
@@ -129,6 +129,14 @@ chroot_facet_mountable::get_details (chroot const&  chroot,
 }
 
 void
+chroot_facet_mountable::get_used_keys (string_list& used_keys) const
+{
+  used_keys.push_back("mount-device");
+  used_keys.push_back("mount-options");
+  used_keys.push_back("location");
+}
+
+void
 chroot_facet_mountable::get_keyfile (chroot const& chroot,
 				     keyfile&      keyfile) const
 {
@@ -150,8 +158,7 @@ chroot_facet_mountable::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_mountable::set_keyfile (chroot&        chroot,
-				     keyfile const& keyfile,
-				     string_list&   used_keys)
+				     keyfile const& keyfile)
 {
   bool session = static_cast<bool>(chroot.get_facet<chroot_facet_session>());
 
@@ -161,17 +168,14 @@ chroot_facet_mountable::set_keyfile (chroot&        chroot,
 			    session ?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_DISALLOWED);
-  used_keys.push_back("mount-device");
 
   keyfile::get_object_value(*this, &chroot_facet_mountable::set_mount_options,
 			    keyfile, chroot.get_name(),
 			    "mount-options",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("mount-options");
 
   keyfile::get_object_value(*this, &chroot_facet_mountable::set_location,
 			    keyfile, chroot.get_name(),
 			    "location",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("location");
 }
diff --git a/sbuild/sbuild-chroot-facet-mountable.h b/sbuild/sbuild-chroot-facet-mountable.h
index 73e63379..703cd63e 100644
--- a/sbuild/sbuild-chroot-facet-mountable.h
+++ b/sbuild/sbuild-chroot-facet-mountable.h
@@ -128,13 +128,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// The device to mount.
diff --git a/sbuild/sbuild-chroot-facet-personality.cc b/sbuild/sbuild-chroot-facet-personality.cc
index ce6a1c07..c9114d46 100644
--- a/sbuild/sbuild-chroot-facet-personality.cc
+++ b/sbuild/sbuild-chroot-facet-personality.cc
@@ -90,6 +90,12 @@ chroot_facet_personality::get_details (chroot const&  chroot,
 }
 
 void
+chroot_facet_personality::get_used_keys (string_list& used_keys) const
+{
+  used_keys.push_back("personality");
+}
+
+void
 chroot_facet_personality::get_keyfile (chroot const& chroot,
 				       keyfile&      keyfile) const
 {
@@ -101,11 +107,9 @@ chroot_facet_personality::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_personality::set_keyfile (chroot&        chroot,
-				       keyfile const& keyfile,
-				       string_list&   used_keys)
+				       keyfile const& keyfile)
 {
   keyfile::get_object_value(*this, &chroot_facet_personality::set_persona,
 			    keyfile, chroot.get_name(), "personality",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("personality");
 }
diff --git a/sbuild/sbuild-chroot-facet-personality.h b/sbuild/sbuild-chroot-facet-personality.h
index e72c59e2..f6d856c5 100644
--- a/sbuild/sbuild-chroot-facet-personality.h
+++ b/sbuild/sbuild-chroot-facet-personality.h
@@ -87,13 +87,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// Process execution domain (Linux only).
diff --git a/sbuild/sbuild-chroot-facet-session-clonable.cc b/sbuild/sbuild-chroot-facet-session-clonable.cc
index c6dbb07e..dcf3e5ce 100644
--- a/sbuild/sbuild-chroot-facet-session-clonable.cc
+++ b/sbuild/sbuild-chroot-facet-session-clonable.cc
@@ -235,6 +235,11 @@ chroot_facet_session_clonable::get_details (chroot const&  chroot,
 }
 
 void
+chroot_facet_session_clonable::get_used_keys (string_list& used_keys) const
+{
+}
+
+void
 chroot_facet_session_clonable::get_keyfile (chroot const& chroot,
 					    keyfile&      keyfile) const
 {
@@ -242,7 +247,6 @@ chroot_facet_session_clonable::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_session_clonable::set_keyfile (chroot&        chroot,
-					    keyfile const& keyfile,
-					    string_list&   used_keys)
+					    keyfile const& keyfile)
 {
 }
diff --git a/sbuild/sbuild-chroot-facet-session-clonable.h b/sbuild/sbuild-chroot-facet-session-clonable.h
index 08618b9b..19040813 100644
--- a/sbuild/sbuild-chroot-facet-session-clonable.h
+++ b/sbuild/sbuild-chroot-facet-session-clonable.h
@@ -91,13 +91,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
   };
 
 }
diff --git a/sbuild/sbuild-chroot-facet-session.cc b/sbuild/sbuild-chroot-facet-session.cc
index 7b134142..df115fcd 100644
--- a/sbuild/sbuild-chroot-facet-session.cc
+++ b/sbuild/sbuild-chroot-facet-session.cc
@@ -129,6 +129,18 @@ chroot_facet_session::get_details (chroot const&  chroot,
 }
 
 void
+chroot_facet_session::get_used_keys (string_list& used_keys) const
+{
+  used_keys.push_back("active");
+  used_keys.push_back("source-users");
+  used_keys.push_back("source-groups");
+  used_keys.push_back("source-root-users");
+  used_keys.push_back("source-root-groups");
+  used_keys.push_back("original-name");
+  used_keys.push_back("selected-name");
+}
+
+void
 chroot_facet_session::get_keyfile (chroot const& chroot,
 				   keyfile&      keyfile) const
 {
@@ -143,8 +155,7 @@ chroot_facet_session::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_session::set_keyfile (chroot&        chroot,
-				   keyfile const& keyfile,
-				   string_list&   used_keys)
+				   keyfile const& keyfile)
 {
   // Null methods for obsolete keys.
   void (chroot_facet_session::* nullmethod)(bool) = 0;
@@ -158,41 +169,34 @@ chroot_facet_session::set_keyfile (chroot&        chroot,
 			    keyfile, chroot.get_name(),
 			    "active",
 			    keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("active");
 
   keyfile::get_object_list_value(*this, nullvmethod,
 				 keyfile, chroot.get_name(),
 				 "source-users",
 				 keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("source-users");
 
   keyfile::get_object_list_value(*this, nullvmethod,
 				 keyfile, chroot.get_name(),
 				 "source-groups",
 				 keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("source-groups");
 
   keyfile::get_object_list_value(*this, nullvmethod,
 				 keyfile, chroot.get_name(),
 				 "source-root-users",
 				 keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("source-root-users");
 
   keyfile::get_object_list_value(*this, nullvmethod,
 				 keyfile, chroot.get_name(),
 				 "source-root-groups",
 				 keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("source-root-groups");
 
   keyfile::get_object_value(*this, &chroot_facet_session::set_original_name,
 			    keyfile, chroot.get_name(),
 			    "original-name",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("original-name");
 
   keyfile::get_object_value(*this, &chroot_facet_session::set_selected_name,
 			    keyfile, chroot.get_name(),
 			    "selected-name",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("selected-name");
 }
diff --git a/sbuild/sbuild-chroot-facet-session.h b/sbuild/sbuild-chroot-facet-session.h
index 57c2af26..f6b469f8 100644
--- a/sbuild/sbuild-chroot-facet-session.h
+++ b/sbuild/sbuild-chroot-facet-session.h
@@ -108,13 +108,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// Original chroot name prior to session cloning.
diff --git a/sbuild/sbuild-chroot-facet-source-clonable.cc b/sbuild/sbuild-chroot-facet-source-clonable.cc
index d4373564..411f6c54 100644
--- a/sbuild/sbuild-chroot-facet-source-clonable.cc
+++ b/sbuild/sbuild-chroot-facet-source-clonable.cc
@@ -164,6 +164,16 @@ chroot_facet_source_clonable::get_session_flags (chroot const& chroot) const
 }
 
 void
+chroot_facet_source_clonable::get_used_keys (string_list& used_keys) const
+{
+  used_keys.push_back("source-clone");
+  used_keys.push_back("source-users");
+  used_keys.push_back("source-groups");
+  used_keys.push_back("source-root-users");
+  used_keys.push_back("source-root-groups");
+}
+
+void
 chroot_facet_source_clonable::get_details (chroot const&  chroot,
 					   format_detail& detail) const
 {
@@ -201,36 +211,30 @@ chroot_facet_source_clonable::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_source_clonable::set_keyfile (chroot&        chroot,
-					   keyfile const& keyfile,
-					   string_list&   used_keys)
+					   keyfile const& keyfile)
 {
   keyfile::get_object_value(*this, &chroot_facet_source_clonable::set_source_clone,
 			    keyfile, chroot.get_name(),
 			    "source-clone",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("source-clone");
 
   keyfile::get_object_list_value(*this, &chroot_facet_source_clonable::set_source_users,
 				 keyfile, chroot.get_name(),
 				 "source-users",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("source-users");
 
   keyfile::get_object_list_value(*this, &chroot_facet_source_clonable::set_source_groups,
 				 keyfile, chroot.get_name(),
 				 "source-groups",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("source-groups");
 
   keyfile::get_object_list_value(*this, &chroot_facet_source_clonable::set_source_root_users,
 				 keyfile, chroot.get_name(),
 				 "source-root-users",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("source-root-users");
 
   keyfile::get_object_list_value(*this, &chroot_facet_source_clonable::set_source_root_groups,
 				 keyfile, chroot.get_name(),
 				 "source-root-groups",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("source-root-groups");
 }
diff --git a/sbuild/sbuild-chroot-facet-source-clonable.h b/sbuild/sbuild-chroot-facet-source-clonable.h
index a9b0fad5..c93d9a75 100644
--- a/sbuild/sbuild-chroot-facet-source-clonable.h
+++ b/sbuild/sbuild-chroot-facet-source-clonable.h
@@ -175,13 +175,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// Is source chroot cloning permitted?
diff --git a/sbuild/sbuild-chroot-facet-source.cc b/sbuild/sbuild-chroot-facet-source.cc
index 757c4069..0d624e08 100644
--- a/sbuild/sbuild-chroot-facet-source.cc
+++ b/sbuild/sbuild-chroot-facet-source.cc
@@ -75,6 +75,11 @@ chroot_facet_source::get_details (chroot const&  chroot,
 }
 
 void
+chroot_facet_source::get_used_keys (string_list& used_keys) const
+{
+}
+
+void
 chroot_facet_source::get_keyfile (chroot const& chroot,
 				  keyfile&      keyfile) const
 {
@@ -82,7 +87,6 @@ chroot_facet_source::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_source::set_keyfile (chroot&        chroot,
-				  keyfile const& keyfile,
-				  string_list&   used_keys)
+				  keyfile const& keyfile)
 {
 }
diff --git a/sbuild/sbuild-chroot-facet-source.h b/sbuild/sbuild-chroot-facet-source.h
index 134d7052..2f26c12a 100644
--- a/sbuild/sbuild-chroot-facet-source.h
+++ b/sbuild/sbuild-chroot-facet-source.h
@@ -75,13 +75,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
   };
 
 }
diff --git a/sbuild/sbuild-chroot-facet-union.cc b/sbuild/sbuild-chroot-facet-union.cc
index c446b775..263fabc9 100644
--- a/sbuild/sbuild-chroot-facet-union.cc
+++ b/sbuild/sbuild-chroot-facet-union.cc
@@ -215,6 +215,15 @@ chroot_facet_union::get_details (chroot const& chroot,
 }
 
 void
+chroot_facet_union::get_used_keys (string_list& used_keys) const
+{
+  used_keys.push_back("union-type");
+  used_keys.push_back("union-mount-options");
+  used_keys.push_back("union-overlay-directory");
+  used_keys.push_back("union-underlay-directory");
+}
+
+void
 chroot_facet_union::get_keyfile (chroot const& chroot,
 				 keyfile&      keyfile) const
 {
@@ -242,27 +251,24 @@ chroot_facet_union::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_union::set_keyfile (chroot&        chroot,
-				 keyfile const& keyfile,
-				 string_list&   used_keys)
+				 keyfile const& keyfile)
 {
   bool session = static_cast<bool>(chroot.get_facet<chroot_facet_session>());
 
   keyfile::get_object_value(*this, &chroot_facet_union::set_union_type,
 			    keyfile, chroot.get_name(), "union-type",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("union-type");
 
   // If we are a union, add specific source options here.
   chroot_facet_source_clonable::ptr psrc
     (chroot.get_facet<chroot_facet_source_clonable>());
   if (psrc)
-    psrc->set_keyfile(chroot, keyfile, used_keys);
+    psrc->set_keyfile(chroot, keyfile);
 
   keyfile::get_object_value(*this,
 			    &chroot_facet_union::set_union_mount_options,
 			    keyfile, chroot.get_name(), "union-mount-options",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("union-mount-options");
 
   keyfile::get_object_value(*this,
 			    &chroot_facet_union::set_union_overlay_directory,
@@ -271,7 +277,6 @@ chroot_facet_union::set_keyfile (chroot&        chroot,
 			    (session && get_union_configured())?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("union-overlay-directory");
 
   keyfile::get_object_value(*this,
 			    &chroot_facet_union::set_union_underlay_directory,
@@ -280,5 +285,4 @@ chroot_facet_union::set_keyfile (chroot&        chroot,
 			    (session && get_union_configured())?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("union-underlay-directory");
 }
diff --git a/sbuild/sbuild-chroot-facet-union.h b/sbuild/sbuild-chroot-facet-union.h
index c1dd5344..1f3e7dc9 100644
--- a/sbuild/sbuild-chroot-facet-union.h
+++ b/sbuild/sbuild-chroot-facet-union.h
@@ -171,13 +171,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// filesystem union type.
diff --git a/sbuild/sbuild-chroot-facet-userdata.cc b/sbuild/sbuild-chroot-facet-userdata.cc
index 4cd37c27..d100eca2 100644
--- a/sbuild/sbuild-chroot-facet-userdata.cc
+++ b/sbuild/sbuild-chroot-facet-userdata.cc
@@ -334,6 +334,13 @@ chroot_facet_userdata::set_root_modifiable_keys (string_set const& keys)
 }
 
 void
+chroot_facet_userdata::get_used_keys (string_list& used_keys) const
+{
+  used_keys.push_back("user-modifiable-keys");
+  used_keys.push_back("root-modifiable-keys");
+}
+
+void
 chroot_facet_userdata::get_keyfile (chroot const& chroot,
 				    keyfile&      keyfile) const
 {
@@ -359,20 +366,17 @@ chroot_facet_userdata::get_keyfile (chroot const& chroot,
 
 void
 chroot_facet_userdata::set_keyfile (chroot&        chroot,
-				    keyfile const& keyfile,
-				    string_list&   used_keys)
+				    keyfile const& keyfile)
 {
   keyfile::get_object_set_value(*this,
 				&chroot_facet_userdata::set_user_modifiable_keys,
 				keyfile, chroot.get_name(),
 				"user-modifiable-keys",
 				keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("user-modifiable-keys");
 
   keyfile::get_object_set_value(*this,
 				&chroot_facet_userdata::set_root_modifiable_keys,
 				keyfile, chroot.get_name(),
 				"root-modifiable-keys",
 				keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("root-modifiable-keys");
 }
diff --git a/sbuild/sbuild-chroot-facet.h b/sbuild/sbuild-chroot-facet.h
index b0075d8f..1e3654ea 100644
--- a/sbuild/sbuild-chroot-facet.h
+++ b/sbuild/sbuild-chroot-facet.h
@@ -115,6 +115,14 @@ namespace sbuild
 		 format_detail& detail) const = 0;
 
     /**
+     * Get a list of the keys used during keyfile parsing.
+     *
+     * @returns a list of key names.
+     */
+    virtual void
+    get_used_keys (string_list& used_keys) const = 0;
+
+    /**
      * Copy the chroot properties into a keyfile.  The keyfile group
      * with the name of the chroot will be set; if it already exists,
      * it will be removed before setting it.
@@ -137,8 +145,7 @@ namespace sbuild
      */
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys) = 0;
+		 keyfile const& keyfile) = 0;
 
   protected:
     /// Chroot owning this facet.
diff --git a/sbuild/sbuild-chroot-file.cc b/sbuild/sbuild-chroot-file.cc
index 44f534d7..e6a7827b 100644
--- a/sbuild/sbuild-chroot-file.cc
+++ b/sbuild/sbuild-chroot-file.cc
@@ -222,6 +222,16 @@ chroot_file::get_details (chroot const&  chroot,
 }
 
 void
+chroot_file::get_used_keys (string_list& used_keys) const
+{
+  chroot::get_used_keys(used_keys);
+
+  used_keys.push_back("file");
+  used_keys.push_back("location");
+  used_keys.push_back("file-repack");
+}
+
+void
 chroot_file::get_keyfile (chroot const& chroot,
 			  keyfile&      keyfile) const
 {
@@ -243,28 +253,24 @@ chroot_file::get_keyfile (chroot const& chroot,
 
 void
 chroot_file::set_keyfile (chroot&        chroot,
-			  keyfile const& keyfile,
-			  string_list&   used_keys)
+			  keyfile const& keyfile)
 {
-  chroot::set_keyfile(chroot, keyfile, used_keys);
+  chroot::set_keyfile(chroot, keyfile);
 
   bool session = static_cast<bool>(get_facet<chroot_facet_session>());
 
   keyfile::get_object_value(*this, &chroot_file::set_file,
 			    keyfile, get_name(), "file",
 			    keyfile::PRIORITY_REQUIRED);
-  used_keys.push_back("file");
 
   keyfile::get_object_value(*this, &chroot_file::set_location,
 			    keyfile, chroot.get_name(),
 			    "location",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("location");
 
   keyfile::get_object_value(*this, &chroot_file::set_file_repack,
 			    keyfile, get_name(), "file-repack",
 			    session ?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_DISALLOWED);
-  used_keys.push_back("file-repack");
 }
diff --git a/sbuild/sbuild-chroot-file.h b/sbuild/sbuild-chroot-file.h
index b32f92ca..7b6ad05f 100644
--- a/sbuild/sbuild-chroot-file.h
+++ b/sbuild/sbuild-chroot-file.h
@@ -133,13 +133,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// The file to use.
diff --git a/sbuild/sbuild-chroot-loopback.cc b/sbuild/sbuild-chroot-loopback.cc
index 69de3f05..a3417caa 100644
--- a/sbuild/sbuild-chroot-loopback.cc
+++ b/sbuild/sbuild-chroot-loopback.cc
@@ -185,6 +185,14 @@ chroot_loopback::get_details (chroot const&  chroot,
 }
 
 void
+chroot_loopback::get_used_keys (string_list& used_keys) const
+{
+  chroot::get_used_keys(used_keys);
+
+  used_keys.push_back("file");
+}
+
+void
 chroot_loopback::get_keyfile (chroot const& chroot,
 			      keyfile&      keyfile) const
 {
@@ -196,13 +204,11 @@ chroot_loopback::get_keyfile (chroot const& chroot,
 
 void
 chroot_loopback::set_keyfile (chroot&        chroot,
-			      keyfile const& keyfile,
-			      string_list&   used_keys)
+			      keyfile const& keyfile)
 {
-  chroot::set_keyfile(chroot, keyfile, used_keys);
+  chroot::set_keyfile(chroot, keyfile);
 
   keyfile::get_object_value(*this, &chroot_loopback::set_file,
 			    keyfile, get_name(), "file",
 			    keyfile::PRIORITY_REQUIRED);
-  used_keys.push_back("file");
 }
diff --git a/sbuild/sbuild-chroot-loopback.h b/sbuild/sbuild-chroot-loopback.h
index ee3b03bd..722a95d3 100644
--- a/sbuild/sbuild-chroot-loopback.h
+++ b/sbuild/sbuild-chroot-loopback.h
@@ -101,13 +101,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile&      keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// The file to use.
diff --git a/sbuild/sbuild-chroot-lvm-snapshot.cc b/sbuild/sbuild-chroot-lvm-snapshot.cc
index 629b502b..d41853f8 100644
--- a/sbuild/sbuild-chroot-lvm-snapshot.cc
+++ b/sbuild/sbuild-chroot-lvm-snapshot.cc
@@ -239,6 +239,15 @@ chroot_lvm_snapshot::get_details (chroot const& chroot,
 }
 
 void
+chroot_lvm_snapshot::get_used_keys (string_list& used_keys) const
+{
+  chroot_block_device_base::get_used_keys(used_keys);
+
+  used_keys.push_back("lvm-snapshot-device");
+  used_keys.push_back("lvm-snapshot-options");
+}
+
+void
 chroot_lvm_snapshot::get_keyfile (chroot const& chroot,
 				  keyfile& keyfile) const
 {
@@ -261,10 +270,9 @@ chroot_lvm_snapshot::get_keyfile (chroot const& chroot,
 
 void
 chroot_lvm_snapshot::set_keyfile (chroot&        chroot,
-				  keyfile const& keyfile,
-				  string_list&   used_keys)
+				  keyfile const& keyfile)
 {
-  chroot_block_device_base::set_keyfile(chroot, keyfile, used_keys);
+  chroot_block_device_base::set_keyfile(chroot, keyfile);
 
   bool session = static_cast<bool>(get_facet<chroot_facet_session>());
 
@@ -273,12 +281,10 @@ chroot_lvm_snapshot::set_keyfile (chroot&        chroot,
 			    session ?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_DISALLOWED);
-  used_keys.push_back("lvm-snapshot-device");
 
   keyfile::get_object_value(*this, &chroot_lvm_snapshot::set_snapshot_options,
 			    keyfile, get_name(), "lvm-snapshot-options",
 			    session ?
 			    keyfile::PRIORITY_DEPRECATED :
 			    keyfile::PRIORITY_REQUIRED); // Only needed for creating snapshot, not using snapshot
-  used_keys.push_back("lvm-snapshot-options");
 }
diff --git a/sbuild/sbuild-chroot-lvm-snapshot.h b/sbuild/sbuild-chroot-lvm-snapshot.h
index b955fbe0..d4a04049 100644
--- a/sbuild/sbuild-chroot-lvm-snapshot.h
+++ b/sbuild/sbuild-chroot-lvm-snapshot.h
@@ -113,13 +113,15 @@ namespace sbuild
 		 format_detail& detail) const;
 
     virtual void
+    get_used_keys (string_list& used_keys) const;
+
+    virtual void
     get_keyfile (chroot const& chroot,
 		 keyfile& keyfile) const;
 
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys);
+		 keyfile const& keyfile);
 
   private:
     /// LVM snapshot device name for lvcreate.
diff --git a/sbuild/sbuild-chroot.cc b/sbuild/sbuild-chroot.cc
index 8e64346a..01e4a63a 100644
--- a/sbuild/sbuild-chroot.cc
+++ b/sbuild/sbuild-chroot.cc
@@ -713,6 +713,51 @@ sbuild::chroot::print_details (std::ostream& stream) const
   stream << fmt;
 }
 
+string_list
+sbuild::chroot::get_used_keys () const
+{
+  string_list used_keys;
+
+  get_used_keys(used_keys);
+
+  for (facet_list::const_iterator pos = facets.begin();
+       pos != facets.end();
+       ++pos)
+    {
+      (*pos)->get_used_keys(used_keys);
+    }
+
+  return used_keys;
+}
+
+void
+sbuild::chroot::get_used_keys (string_list& used_keys) const
+{
+  // Keys which are used elsewhere, but should be counted as "used".
+  used_keys.push_back("type");
+
+  used_keys.push_back("active");
+  used_keys.push_back("run-setup-scripts");
+  used_keys.push_back("run-session-scripts");
+  used_keys.push_back("run-exec-scripts");
+  used_keys.push_back("profile");
+  used_keys.push_back("script-config");
+  used_keys.push_back("priority");
+  used_keys.push_back("aliases");
+  used_keys.push_back("environment-filter");
+  used_keys.push_back("description");
+  used_keys.push_back("users");
+  used_keys.push_back("groups");
+  used_keys.push_back("root-users");
+  used_keys.push_back("root-groups");
+  used_keys.push_back("mount-location");
+  used_keys.push_back("name");
+  used_keys.push_back("command-prefix");
+  used_keys.push_back("message-verbosity");
+  used_keys.push_back("preserve-environment");
+  used_keys.push_back("shell");
+}
+
 void
 sbuild::chroot::get_keyfile (keyfile& keyfile) const
 {
@@ -805,15 +850,13 @@ sbuild::chroot::get_keyfile (chroot const& chroot,
 void
 sbuild::chroot::set_keyfile (keyfile const& keyfile)
 {
-  string_list used_keys;
-
-  set_keyfile(*this, keyfile, used_keys);
+  set_keyfile(*this, keyfile);
 
   for (facet_list::const_iterator pos = facets.begin();
        pos != facets.end();
        ++pos)
     {
-      (*pos)->set_keyfile(*this, keyfile, used_keys);
+      (*pos)->set_keyfile(*this, keyfile);
     }
 
   // Check for keys which weren't set above.  These may be either
@@ -821,6 +864,7 @@ sbuild::chroot::set_keyfile (keyfile const& keyfile)
   // separated with one or more periods.  These may be later
   // overridden by the user on the commandline.
   {
+    string_list used_keys = get_used_keys();
     std::string const& group = this->get_name();
     const string_list total(keyfile.get_keys(group));
 
@@ -840,6 +884,11 @@ sbuild::chroot::set_keyfile (keyfile const& keyfile)
 	 pos != unused.end();
 	 ++pos)
       {
+	// Skip language-specific key variants.
+	static regex description_keys("\\[.*\\]$");
+	if (regex_search(*pos, description_keys))
+	  continue;
+
 	if (userdata)
 	  {
 	    try
@@ -882,32 +931,17 @@ sbuild::chroot::set_keyfile (keyfile const& keyfile)
 
 void
 sbuild::chroot::set_keyfile (chroot&        chroot,
-			     keyfile const& keyfile,
-			     string_list&   used_keys)
+			     keyfile const& keyfile)
 {
   // Null method for obsolete keys.
   void (sbuild::chroot::* nullmethod)(bool) = 0;
 
   bool session = static_cast<bool>(get_facet<chroot_facet_session>());
 
-  // Keys which are used elsewhere, but should be counted as "used".
-  used_keys.push_back("type");
-
-  string_list keys = keyfile.get_keys(chroot.get_name());
-  for (string_list::const_iterator pos = keys.begin();
-       pos != keys.end();
-       ++pos)
-    {
-      static regex description_keys("^description\\[.*\\]$");
-      if (regex_search(*pos, description_keys))
-	used_keys.push_back(*pos);
-    }
-
   keyfile::get_object_value(chroot, nullmethod,
 			    keyfile, chroot.get_name(),
 			    "active",
 			    keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("active");
 
   // Setup scripts are run depending on the chroot type in use, and is
   // no longer user-configurable.  They need to run for all types
@@ -916,7 +950,6 @@ sbuild::chroot::set_keyfile (chroot&        chroot,
 			    keyfile, chroot.get_name(),
 			    "run-setup-scripts",
 			    keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("run-setup-scripts");
 
   // Exec scripts have been removed, so these two calls do nothing
   // except to warn the user that the options are no longer used.
@@ -924,18 +957,15 @@ sbuild::chroot::set_keyfile (chroot&        chroot,
 			    keyfile, chroot.get_name(),
 			    "run-session-scripts",
 			    keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("run-session-scripts");
   keyfile::get_object_value(chroot, nullmethod,
 			    keyfile, chroot.get_name(),
 			    "run-exec-scripts",
 			    keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("run-exec-scripts");
 
   keyfile::get_object_value(chroot, &chroot::set_profile,
 			    keyfile, chroot.get_name(),
 			    "profile",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("profile");
 
   keyfile::get_object_value(chroot, &chroot::set_script_config,
 			    keyfile, chroot.get_name(),
@@ -943,7 +973,6 @@ sbuild::chroot::set_keyfile (chroot&        chroot,
 			    session ?
 			    keyfile::PRIORITY_OPTIONAL :
 			    keyfile::PRIORITY_DEPRECATED);
-  used_keys.push_back("script-config");
 
   keyfile::get_object_value(chroot, nullmethod,
 			    keyfile, chroot.get_name(),
@@ -951,49 +980,41 @@ sbuild::chroot::set_keyfile (chroot&        chroot,
 			    session ?
 			    keyfile::PRIORITY_OPTIONAL :
 			    keyfile::PRIORITY_OBSOLETE);
-  used_keys.push_back("priority");
 
   keyfile::get_object_list_value(chroot, &chroot::set_aliases,
 				 keyfile, chroot.get_name(),
 				 "aliases",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("aliases");
 
   keyfile::get_object_value(chroot, &chroot::set_environment_filter,
 			    keyfile, chroot.get_name(),
 			    "environment-filter",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("environment-filter");
 
   keyfile::get_object_value(chroot, &chroot::set_description,
 			    keyfile, chroot.get_name(),
 			    "description",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("description");
 
   keyfile::get_object_list_value(chroot, &chroot::set_users,
 				 keyfile, chroot.get_name(),
 				 "users",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("users");
 
   keyfile::get_object_list_value(chroot, &chroot::set_groups,
 				 keyfile, chroot.get_name(),
 				 "groups",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("groups");
 
   keyfile::get_object_list_value(chroot, &chroot::set_root_users,
 				 keyfile, chroot.get_name(),
 				 "root-users",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("root-users");
 
   keyfile::get_object_list_value(chroot, &chroot::set_root_groups,
 				 keyfile, chroot.get_name(),
 				 "root-groups",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("root-groups");
 
   keyfile::get_object_value(chroot, &chroot::set_mount_location,
 			    keyfile, chroot.get_name(),
@@ -1001,7 +1022,6 @@ sbuild::chroot::set_keyfile (chroot&        chroot,
 			    session ?
 			    keyfile::PRIORITY_REQUIRED :
 			    keyfile::PRIORITY_DISALLOWED);
-  used_keys.push_back("mount-location");
 
   keyfile::get_object_value(chroot, &chroot::set_name,
 			    keyfile, chroot.get_name(),
@@ -1009,29 +1029,24 @@ sbuild::chroot::set_keyfile (chroot&        chroot,
 			    session ?
 			    keyfile::PRIORITY_OPTIONAL :
 			    keyfile::PRIORITY_DISALLOWED);
-  used_keys.push_back("name");
 
   keyfile::get_object_list_value(chroot, &chroot::set_command_prefix,
 				 keyfile, chroot.get_name(),
 				 "command-prefix",
 				 keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("command-prefix");
 
   keyfile::get_object_value(chroot, &chroot::set_verbosity,
 			    keyfile, chroot.get_name(),
 			    "message-verbosity",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("message-verbosity");
 
   keyfile::get_object_value(chroot, &chroot::set_preserve_environment,
 			    keyfile, chroot.get_name(),
 			    "preserve-environment",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("preserve-environment");
 
   keyfile::get_object_value(chroot, &chroot::set_default_shell,
 			    keyfile, chroot.get_name(),
 			    "shell",
 			    keyfile::PRIORITY_OPTIONAL);
-  used_keys.push_back("shell");
 }
diff --git a/sbuild/sbuild-chroot.h b/sbuild/sbuild-chroot.h
index ea325667..ab3fb0c9 100644
--- a/sbuild/sbuild-chroot.h
+++ b/sbuild/sbuild-chroot.h
@@ -776,7 +776,18 @@ namespace sbuild
     void
     set_keyfile (keyfile const& keyfile);
 
+    /**
+     * Get a list of the keys used during keyfile parsing.
+     *
+     * @returns a list of key names.
+     */
+    string_list
+    get_used_keys () const;
+
   protected:
+    virtual void
+    get_used_keys (string_list& used_keys) const = 0;
+
     /**
      * Set the chroot properties from a keyfile.  The chroot name must
      * have previously been set, so that the correct keyfile group may
@@ -788,8 +799,7 @@ namespace sbuild
      */
     virtual void
     set_keyfile (chroot&        chroot,
-		 keyfile const& keyfile,
-		 string_list&   used_keys) = 0;
+		 keyfile const& keyfile) = 0;
 
   private:
     /// Chroot name.