From 36dc58bf3501990d9ffa12f2bccfdd83b889c140 Mon Sep 17 00:00:00 2001
From: Nils Philippsen <nils@redhat.com>
Date: Aug 20 2018 10:54:05 +0000
Subject: [PATCH 1/3] catch errno == ENOENT if mbs-manager is missing


Sometimes a missing mbs-manager will cause exceptions that don't have
the exact same error message. Additionally, test for wrapped exceptions
with an errno set to ENOENT.

Signed-off-by: Nils Philippsen <nils@redhat.com>

---

diff --git a/pyrpkg/__init__.py b/pyrpkg/__init__.py
index c094e8a..a32c920 100644
--- a/pyrpkg/__init__.py
+++ b/pyrpkg/__init__.py
@@ -3155,7 +3155,11 @@ class Commands(object):
         try:
             self._run_command(command, env=env)
         except rpkgError as e:
-            if str(e) == '[Errno 2] No such file or directory':
+            e_errno = None
+            if e.args and isinstance(e.args[0], Exception):
+                e_errno = getattr(e.args[0], 'errno', None)
+            if (e_errno == errno.ENOENT
+                    or str(e) == '[Errno 2] No such file or directory'):
                 raise rpkgError('mbs-manager is missing. Please install '
                                 'module-build-service.')
             else:

From 049a53497023bb6e2388936373c7837f89228d8f Mon Sep 17 00:00:00 2001
From: Nils Philippsen <nils@redhat.com>
Date: Aug 20 2018 10:54:05 +0000
Subject: [PATCH 2/3] test for missing mbs-manager with errno set


Signed-off-by: Nils Philippsen <nils@redhat.com>

---

diff --git a/tests/test_cli.py b/tests/test_cli.py
index b5939a6..ea35afe 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -10,6 +10,7 @@ import subprocess
 import sys
 import tempfile
 import koji_cli.lib
+import errno
 
 try:
     import unittest2 as unittest
@@ -2625,6 +2626,37 @@ State:    failed
             six.assertRaisesRegex(self, rpkgError, r'mbs-manager is missing.+',
                                   cli.module_build_local)
 
+    @patch.object(Commands, '_run_command')
+    def test_module_build_local_mbs_manager_is_missing_with_errno(
+            self, mock_run):
+        """
+        Test submitting a local module build with mbs-manager missing #2.
+        """
+        try:
+            exc = FileNotFoundError
+        except NameError:
+            exc = IOError
+
+        mock_run.side_effect = rpkgError(exc(
+            errno.ENOENT,
+            "[Errno 2] No such file or directory:"
+            " 'mbs-manager': 'mbs-manager'"))
+
+        cli_cmd = [
+            'rpkg', '--path', self.cloned_repo_path, 'module-build-local'
+        ]
+        with patch('sys.argv', new=cli_cmd):
+            cli = self.new_cli()
+
+            # we create an empty file for the purpose of this test so we don't
+            # raise an exception
+            modulemd_yml = os.path.join(self.cloned_repo_path,
+                                        cli.cmd.repo_name + '.yaml')
+            self.write_file(modulemd_yml)
+
+            six.assertRaisesRegex(self, rpkgError, r'mbs-manager is missing.+',
+                                  cli.module_build_local)
+
 
 class TestOptionNameAndNamespace(CliTestCase):
     """Test CLI option --name and --namespace"""

From c80daf69204b0cc44789427ce13a9e0864a0a4d6 Mon Sep 17 00:00:00 2001
From: Nils Philippsen <nils@redhat.com>
Date: Aug 20 2018 11:42:30 +0000
Subject: [PATCH 3/3] explain mbs-manager exception handling


Signed-off-by: Nils Philippsen <nils@redhat.com>

---

diff --git a/pyrpkg/__init__.py b/pyrpkg/__init__.py
index a32c920..57c2169 100644
--- a/pyrpkg/__init__.py
+++ b/pyrpkg/__init__.py
@@ -3155,6 +3155,13 @@ class Commands(object):
         try:
             self._run_command(command, env=env)
         except rpkgError as e:
+            # If the exception wraps another one which has .errno == ENOENT
+            # this indicates that the file (mbs-manager executable) wasn't
+            # found. This works in both Python 2 and 3 which throw different
+            # types of exceptions in this case. We use duck-typing rather than
+            # checking for the respective specific exception types because the
+            # Python 3 FileNotFoundError exception isn't known in Python 2 and
+            # special casing this makes the code unnecessarily complicated.
             e_errno = None
             if e.args and isinstance(e.args[0], Exception):
                 e_errno = getattr(e.args[0], 'errno', None)