packages: Purge packages on uninstall

The primary reason for the existence of uninstall feature is to clean up the
existing working or non-working setup and re-install freshly. It is not to
remove the effects of the installed app since disable works well for that. It is
seldom to free up space since even on a microSD card, the space occupied by most
apps is negligible.

Tests:

- Unit tests pass

- Functional tests for all apps pass (except for known failures).

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/package.py

@@ -175,7 +175,7 @@ class Packages(app_module.FollowerComponent):
            self.conflicts_action not in (None, self.ConflictsAction.IGNORE):
             logger.info('Removing conflicting packages: %s',
                         packages_to_remove)
-            uninstall(packages_to_remove)
+            uninstall(packages_to_remove, purge=False)
 
         install(self.get_actual_packages(),
                 skip_recommends=self.skip_recommends)
@@ -198,7 +198,8 @@ class Packages(app_module.FollowerComponent):
                 packages_set -= set(component.get_actual_packages())
 
         # Preserve order of packages for ease of testing
-        uninstall([package for package in packages if package in packages_set])
+        uninstall([package for package in packages if package in packages_set],
+                  purge=True)
 
     def diagnose(self):
         """Run diagnostics and return results."""
@@ -341,10 +342,11 @@ class Transaction:
             logger.exception('Error installing package: %s', exception)
             raise
 
-    def uninstall(self):
+    def uninstall(self, purge):
         """Run an apt-get transaction to uninstall given packages."""
         try:
-            privileged.remove(app_id=self.app_id, packages=self.package_names)
+            privileged.remove(app_id=self.app_id, packages=self.package_names,
+                              purge=purge)
         except Exception as exception:
             logger.exception('Error uninstalling package: %s', exception)
             raise
@@ -416,7 +418,7 @@ def install(package_names, skip_recommends=False, force_configuration=None,
                         force_missing_configuration)
 
 
-def uninstall(package_names):
+def uninstall(package_names, purge):
     """Uninstall a set of packages."""
     try:
         operation = operation_module.Operation.get_operation()
@@ -437,7 +439,7 @@ def uninstall(package_names):
     from . import package
     transaction = package.Transaction(operation.app_id, package_names)
     operation.thread_data['transaction'] = transaction
-    transaction.uninstall()
+    transaction.uninstall(purge)
 
 
 def is_package_manager_busy():

plinth/privileged/packages.py

@@ -71,7 +71,7 @@ def install(app_id: str, packages: list[str], skip_recommends: bool = False,
 
 
 @privileged
-def remove(app_id: str, packages: list[str]):
+def remove(app_id: str, packages: list[str], purge: bool):
     """Remove packages using apt-get."""
     try:
         _assert_managed_packages(app_id, packages)
@@ -81,7 +81,8 @@ def remove(app_id: str, packages: list[str]):
     subprocess.run(['dpkg', '--configure', '-a'], check=False)
     with action_utils.apt_hold_freedombox():
         run_apt_command(['--fix-broken', 'install'])
-        returncode = run_apt_command(['remove'] + packages)
+        options = [] if not purge else ['--purge']
+        returncode = run_apt_command(['remove'] + options + packages)
 
     if returncode:
         raise RuntimeError(

plinth/tests/test_package.py

@@ -130,7 +130,7 @@ def test_packages_setup_with_conflicts(install, uninstall, packages_installed):
     component = Packages('test-component', ['bash'], conflicts=['exim4-base'],
                          conflicts_action=Packages.ConflictsAction.REMOVE)
     component.setup(old_version=0)
-    uninstall.assert_has_calls([call(['exim4-base'])])
+    uninstall.assert_has_calls([call(['exim4-base'], purge=False)])
     install.assert_has_calls([call(['bash'], skip_recommends=False)])
 
     uninstall.reset_mock()
@@ -162,7 +162,7 @@ def test_packages_uninstall(uninstall):
     app = TestApp()
     app.add(component)
     app.uninstall()
-    uninstall.assert_has_calls([call(['python3', 'bash'])])
+    uninstall.assert_has_calls([call(['python3', 'bash'], purge=True)])
 
 
 @patch('plinth.package.uninstall')
@@ -218,9 +218,10 @@ def test_packages_uninstall_exclusion(cache, uninstall):
     TestApp2()
     TestApp3()
     app1.uninstall()
-    uninstall.assert_has_calls(
-        [call(['package11', 'package3']),
-         call(['package12', 'package3'])])
+    uninstall.assert_has_calls([
+        call(['package11', 'package3'], purge=True),
+        call(['package12', 'package3'], purge=True)
+    ])
 
 
 @patch('apt.Cache')