# 
# 
# patch "tracvc/mtn/basic_io.py"
#  from [645fd874583a084b3a062cfd1a61531424c06289]
#    to [91697e27e19bd7bfd3521ed66b8e662008fd54e9]
# 
============================================================
--- tracvc/mtn/basic_io.py	645fd874583a084b3a062cfd1a61531424c06289
+++ tracvc/mtn/basic_io.py	91697e27e19bd7bfd3521ed66b8e662008fd54e9
@@ -24,7 +24,7 @@
 import re
 
 STR    = r'"(?P<strval>(\\\\|\\"|[^"])*)" *'
-ID     = r'\[(?P<idval>[a-f0-9]{40})\] *'
+ID     = r'\[(?P<idval>[a-f0-9]{40}|)\] *'
 VAL    = STR + r'|' + ID
 LINE   = r' *(?P<key>\w+) *(?P<values>(' + VAL + r')+)' + '\n'
 STANZA = r'(?P<stanza>(' + LINE + r')+)(\n|$)'
@@ -40,25 +40,33 @@
         yield match.group('stanza')
 
 def get_pairs(stanza):
-    """Generator, returns (key, value) pairs in one stanza."""
+    """
+    Generator, returns (key, value) pairs in one stanza.
+
+    Empty string values ("") are passed through, while empty
+    revision ids ([]) are converted to None.
+
+    If a key exists more than once in a stanza, value becomes a list
+    containing all the values.
+    """
     for match in LINE_RULE.finditer(stanza):
         key = match.group('key')
 
         values = match.group('values')
         valarray = []
         for match in VAL_RULE.finditer(values):
-            value = match.group('strval') or match.group('idval')
-            if value:
+            value = match.group('strval')
+            if value != None:
                 # dequote: replace \" with "
                 value = re.sub(r'\\"', '"', value)
                 # dequote: replace \\ with \
                 value = re.sub(r'\\\\', r'\\', value)
-                valarray.append(value)
+            else:
+                value = match.group('idval') or None
+            valarray.append(value)
 
         if len(valarray) == 1:
             yield key, valarray[0]
-        elif not valarray:
-            yield key, ''
         else:
             yield key, valarray