From ad2a6e34086a717fa5aec14207a2f59012b4758b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marta=20Marczykowska-G=C3=B3recka?=
 <marta.maria.gorecka@gmail.com>
Date: Fri, 20 Jul 2018 00:21:47 +0200
Subject: [PATCH 1/2] Better information on error in qvm-remove

If qvm-remove fails because the VM is in use, it will display
information about where it is used.

fixes QubesOS/qubes-issues#3193
---
 qubesadmin/exc.py              |  4 ++++
 qubesadmin/tools/qvm_remove.py | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/qubesadmin/exc.py b/qubesadmin/exc.py
index 169caa7..9fd024e 100644
--- a/qubesadmin/exc.py
+++ b/qubesadmin/exc.py
@@ -85,6 +85,10 @@ class QubesNoTemplateError(QubesVMError):
     '''Cannot start domain, because there is no template'''
 
 
+class QubesVMInUseError(QubesVMError):
+    '''VM is in use, cannot remove.'''
+
+
 class QubesValueError(QubesException, ValueError):
     '''Cannot set some value, because it is invalid, out of bounds, etc.'''
     pass
diff --git a/qubesadmin/tools/qvm_remove.py b/qubesadmin/tools/qvm_remove.py
index ee08c55..b60f66c 100644
--- a/qubesadmin/tools/qvm_remove.py
+++ b/qubesadmin/tools/qvm_remove.py
@@ -25,6 +25,7 @@ import sys
 
 import qubesadmin.exc
 from qubesadmin.tools import QubesArgumentParser
+import qubesadmin.utils
 
 parser = QubesArgumentParser(description=__doc__,
                              want_app=True,
@@ -47,6 +48,15 @@ def main(args=None, app=None):  # pylint: disable=missing-docstring
         for vm in args.domains:
             try:
                 del args.app.domains[vm.name]
+            except qubesadmin.exc.QubesVMInUseError:
+                dependencies = qubesadmin.utils.vm_dependencies(vm.app, vm)
+                print("VM {} cannot be removed. It is in use as:".format(
+                    vm.name))
+                for (holder, prop) in dependencies:
+                    if holder:
+                        print(" - {} for {}".format(prop, holder.name))
+                    else:
+                        print(" - global property {}".format(prop))
             except qubesadmin.exc.QubesException as e:
                 parser.error_runtime(e)
         retcode = 0

From 47b4e8673601fa95f13a0b60de58de265a1e67ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marta=20Marczykowska-G=C3=B3recka?=
 <marta.maria.gorecka@gmail.com>
Date: Fri, 20 Jul 2018 00:34:21 +0200
Subject: [PATCH 2/2] Added test for qvm-remove dependency reporting

---
 qubesadmin/tests/tools/qvm_remove.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/qubesadmin/tests/tools/qvm_remove.py b/qubesadmin/tests/tools/qvm_remove.py
index 38995b3..3e50e95 100644
--- a/qubesadmin/tests/tools/qvm_remove.py
+++ b/qubesadmin/tests/tools/qvm_remove.py
@@ -21,6 +21,7 @@
 import qubesadmin.tests
 import qubesadmin.tests.tools
 import qubesadmin.tools.qvm_remove
+import unittest.mock
 
 
 class TC_00_qvm_remove(qubesadmin.tests.QubesTestCase):
@@ -33,3 +34,20 @@ class TC_00_qvm_remove(qubesadmin.tests.QubesTestCase):
             b'0\x00\n'
         qubesadmin.tools.qvm_remove.main(['-f', 'some-vm'], app=self.app)
         self.assertAllCalled()
+
+    @unittest.mock.patch('qubesadmin.utils.vm_dependencies')
+    def test_100_dependencies(self, mock_dependencies):
+        self.app.expected_calls[
+            ('dom0', 'admin.vm.List', None, None)] = \
+            b'0\x00some-vm class=AppVM state=Running\n'
+        self.app.expected_calls[
+            ('some-vm', 'admin.vm.Remove', None, None)] = \
+            b'2\x00QubesVMInUseError\x00\x00An error occurred\x00'
+
+        mock_dependencies.return_value = \
+            [(None, 'default_template'), (self.app.domains['some-vm'], 'netvm')]
+
+        qubesadmin.tools.qvm_remove.main(['-f', 'some-vm'], app=self.app)
+
+        self.assertTrue(mock_dependencies.called,
+                        "Dependencies check not called.")