From dd465eb909345f62c9eafb5599f5050e8835090e Mon Sep 17 00:00:00 2001
From: Markus Unterwaditzer <markus@unterwaditzer.net>
Date: Fri, 27 Jan 2017 19:46:31 +0100
Subject: [PATCH] Don't fail when discovery fails

---
 tests/unit/cli/test_discover.py | 18 ++++++++++++++++--
 vdirsyncer/cli/discover.py      | 19 ++++++++++++++-----
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/tests/unit/cli/test_discover.py b/tests/unit/cli/test_discover.py
index bab860c..6f71e85 100644
--- a/tests/unit/cli/test_discover.py
+++ b/tests/unit/cli/test_discover.py
@@ -25,6 +25,20 @@ missing = object()
         ('b3', (missing,
                 {'type': 'fooboo', 'custom_arg': 'b3', 'collection': 'b3'}))
     ]),
+    (['from a', 'from b'], [
+        ('c1', ({'type': 'fooboo', 'custom_arg': 'a1', 'collection': 'c1'},
+                {'type': 'fooboo', 'custom_arg': 'b1', 'collection': 'c1'})),
+        ('c2', ({'type': 'fooboo', 'custom_arg': 'a2', 'collection': 'c2'},
+                {'type': 'fooboo', 'custom_arg': 'b2', 'collection': 'c2'})),
+        ('a3', ({'type': 'fooboo', 'custom_arg': 'a3', 'collection': 'a3'},
+                missing)),
+        ('b3', (missing,
+                {'type': 'fooboo', 'custom_arg': 'b3', 'collection': 'b3'}))
+    ]),
+    ([['c12', 'c1', 'c2']], [
+        ('c12', ({'type': 'fooboo', 'custom_arg': 'a1', 'collection': 'c1'},
+                 {'type': 'fooboo', 'custom_arg': 'b2', 'collection': 'c2'})),
+    ]),
     (None, [
         (None, ({'type': 'fooboo', 'storage_side': 'a', 'collection': None},
                 {'type': 'fooboo', 'storage_side': 'b', 'collection': None}))
@@ -59,9 +73,9 @@ def test_expand_collections(shortcuts, expected):
             'b3': {'type': 'fooboo', 'custom_arg': 'b3', 'collection': 'b3'}
         }
 
-    assert list(expand_collections(
+    assert sorted(expand_collections(
         shortcuts,
         config_a, config_b,
         get_discovered_a, get_discovered_b,
         lambda config, collection: missing
-    )) == expected
+    )) == sorted(expected)
diff --git a/vdirsyncer/cli/discover.py b/vdirsyncer/cli/discover.py
index 268d987..d73df65 100644
--- a/vdirsyncer/cli/discover.py
+++ b/vdirsyncer/cli/discover.py
@@ -3,6 +3,7 @@
 import hashlib
 import json
 import logging
+import sys
 
 from .utils import handle_collection_not_found, handle_storage_init_error, \
     load_status, save_status, storage_class_from_config, \
@@ -65,9 +66,9 @@ def collections_for_pair(status_path, pair, from_cache=True,
 
     if list_collections:
         _print_collections(pair.config_a['instance_name'],
-                           a_discovered.get_self())
+                           a_discovered.get_self)
         _print_collections(pair.config_b['instance_name'],
-                           b_discovered.get_self())
+                           b_discovered.get_self)
 
     # We have to use a list here because the special None/null value would get
     # mangled to string (because JSON objects always have string keys).
@@ -94,7 +95,7 @@ def collections_for_pair(status_path, pair, from_cache=True,
 
 
 def _sanity_check_collections(collections):
-    for collection, (a_args, b_args) in collections:
+    for _, (a_args, b_args) in collections:
         storage_instance_from_config(a_args)
         storage_instance_from_config(b_args)
 
@@ -169,7 +170,8 @@ def expand_collections(shortcuts, config_a, config_b, get_a_discovered,
             else:
                 collection_a = collection_b = collection
 
-            assert collection not in handled_collections
+            if collection in handled_collections:
+                continue
             handled_collections.add(collection)
 
             a_args = _collection_from_discovered(
@@ -197,7 +199,14 @@ def _collection_from_discovered(get_discovered, collection, config,
         return _handle_collection_not_found(config, collection)
 
 
-def _print_collections(instance_name, discovered):
+def _print_collections(instance_name, get_discovered):
+    try:
+        discovered = get_discovered()
+    except Exception:
+        import traceback
+        logger.debug(''.join(traceback.format_tb(sys.exc_info()[2])))
+        logger.warning('Failed to discover collections for {}, use `-vdebug` '
+                       'to see the full traceback.'.format(instance_name))
     logger.info('{}:'.format(instance_name))
     for args in discovered.values():
         collection = args['collection']