--- a/checker.py	Wed Jul 27 23:20:51 2016 +0800
+++ b/checker.py	Sat Jul 30 13:05:59 2016 +0800
@@ -208,25 +208,38 @@
             return False
 
     print('# C&O task: setup')
-
-    requested = []
+    linters = []
+    distinct = []
     for linter in config.get('linters', []):
-        if 'name' in linter and linter['name'] not in requested:
-            requested.append(linter['name'])
-    print('# C&O linters requested: {}'.format(' '.join(requested)))
+        if 'name' not in linter:
+            print("# C&O skipping linter without 'name': {}".format(linter))
+            continue
+        name = linter['name']
+        if 'include' not in linter:
+            print("# C&O skipping '{}': no 'include' in config".format(name))
+            continue
+
+        linters.append(linter)
+        if name not in distinct:
+            distinct.append(name)
+
+    print('# C&O linters requested: {}'.format(' '.join(distinct)))
 
     linter_config = {}
 
-    for linter in config.get('linters', []):
-        if 'name' not in linter:
-            continue
-
+    for linter in linters:
         name = linter['name']
         if name in linter_config:
             continue
 
         lc = read_linter_config(name)
-        if lc is None or 'exec' not in lc:
+
+        if lc is None:
+            print("# C&O skipping '{}': no config".format(name))
+            continue
+
+        if 'exec' not in lc:
+            print("# C&O skipping '{}': no 'exec' in config".format(name))
             continue
 
         linter_config[name] = lc
@@ -243,10 +256,7 @@
     print('# C&O linters installed: {}'.format(' '.join(linter_config.keys())))
 
     print('# C&O task: checks')
-    for linter in config.get('linters', []):
-        if 'name' not in linter or 'include' not in linter:
-            continue
-
+    for linter in linters:
         if linter['name'] not in linter_config:
             continue