[partition] Allow unsafe partitioning decisions

- This is a compile-time choice, and off by default. This may be useful
   for developers that need to get through installation to a different
   partition on their root drive.
 - Add an option to avoid actually doing unsafe things. This is an extra
   safeguard; you need to turn on one and turn off the other option to
   really be unsafe.

src/modules/partition/CMakeLists.txt

@@ -1,3 +1,18 @@
+# When debugging the partitioning widget, or experimenting, you may
+# want to allow unsafe partitioning choices (e.g. doing things to the
+# current disk). Set DEBUG_PARTITION_UNSAFE to allow that (it turns off
+# some filtering of devices).
+option( DEBUG_PARTITION_UNSAFE "Allow unsafe partitioning choices." OFF )
+option( DEBUG_PARTITION_LAME   "Unsafe partitioning will error out on exec." ON )
+
+set( _partition_defs )
+if( DEBUG_PARTITION_UNSAFE )
+    if( DEBUG_PARTITION_LAME )
+        list( APPEND _partition_defs DEBUG_PARTITION_LAME )
+    endif()
+    list( APPEND _partition_defs DEBUG_PARTITION_UNSAFE )
+endif()
+
 find_package(ECM ${ECM_VERSION} REQUIRED NO_MODULE)
 
 include(KDEInstallDirs)
@@ -84,6 +99,7 @@ if ( KPMcore_FOUND )
             kpmcore
             calamaresui
             KF5::CoreAddons
+        COMPILE_DEFINITIONS ${_partition_defs}
         SHARED_LIB
     )
 else()

src/modules/partition/core/DeviceList.cpp

@@ -109,6 +109,9 @@ QList< Device* > getDevices( DeviceType which, qint64 minimumSize )
     CoreBackend* backend = CoreBackendManager::self()->backend();
     DeviceList devices = backend->scanDevices( true );
 
+#ifdef DEBUG_PARTITION_UNSAFE
+    cWarning() << "Allowing unsafe partitioning choices." << devices.count() << "candidates.";
+#else
     cDebug() << "Removing unsuitable devices:" << devices.count() << "candidates.";
 
     // Remove the device which contains / from the list
@@ -142,6 +145,7 @@ QList< Device* > getDevices( DeviceType which, qint64 minimumSize )
         }
         else
             ++it;
+#endif
 
     return devices;
 }