# HG changeset patch
# User Dan Villiom Podlaski Christiansen <danchr@gmail.com>
# Date 1278618839 -7200
# Node ID eea224fa1156a26c23f08cf8b10739d9b5e98ddf
# Parent  493023041e7435c29ed2e2969a13aeb2b733a9bd
svnmeta: improve error message in get_source_rev()

Letting a KeyError propagate when the supplied revision has no
conversion record on file isn't terribly helpful. At least not when
this KeyError merely states that the key missing is
'convert_revision'.  It's much better to preemptively check for it,
detect that it's missing, and then raise an exception with a
descriptive message.

diff --git a/hgsubversion/svnmeta.py b/hgsubversion/svnmeta.py
--- a/hgsubversion/svnmeta.py
+++ b/hgsubversion/svnmeta.py
@@ -424,8 +424,10 @@ class SVNMeta(object):
         """
         if ctx is None:
             ctx = self.repo[changeid]
-        extra = ctx.extra()['convert_revision']
-        branchpath, revnum = extra[40:].rsplit('@', 1)
+        extra = ctx.extra()
+        if 'convert_revision' not in extra:
+            raise KeyError('%s has no conversion record' % ctx)
+        branchpath, revnum = extra['convert_revision'][40:].rsplit('@', 1)
         branch = self.localname(self.normalize(branchpath))
         if self.layout == 'single':
             branchpath = ''