diff --git a/hgext/convert/common.py b/hgext/convert/common.py
--- a/hgext/convert/common.py
+++ b/hgext/convert/common.py
@@ -63,13 +63,13 @@ class converter_source(object):
 
         self.encoding = 'utf-8'
 
-    def checkhexformat(self, revstr):
+    def checkhexformat(self, revstr, mapname='splicemap'):
         """ fails if revstr is not a 40 byte hex. mercurial and git both uses
             such format for their revision numbering
         """
         if not re.match(r'[0-9a-fA-F]{40,40}$', revstr):
-            raise util.Abort(_('splicemap entry %s is not a valid revision'
-                               ' identifier') % revstr)
+            raise util.Abort(_('%s entry %s is not a valid revision'
+                               ' identifier') % (mapname, revstr))
 
     def before(self):
         pass
@@ -172,7 +172,7 @@ class converter_source(object):
         """
         return {}
 
-    def checkrevformat(self, revstr):
+    def checkrevformat(self, revstr, mapname='splicemap'):
         """revstr is a string that describes a revision in the given
            source control system.  Return true if revstr has correct
            format.
diff --git a/hgext/convert/git.py b/hgext/convert/git.py
--- a/hgext/convert/git.py
+++ b/hgext/convert/git.py
@@ -297,7 +297,7 @@ class convert_git(converter_source):
 
         return bookmarks
 
-    def checkrevformat(self, revstr):
+    def checkrevformat(self, revstr, mapname='splicemap'):
         """ git revision string is a 40 byte hex """
-        self.checkhexformat(revstr)
+        self.checkhexformat(revstr, mapname)
 
diff --git a/hgext/convert/hg.py b/hgext/convert/hg.py
--- a/hgext/convert/hg.py
+++ b/hgext/convert/hg.py
@@ -423,6 +423,6 @@ class mercurial_source(converter_source)
     def getbookmarks(self):
         return bookmarks.listbookmarks(self.repo)
 
-    def checkrevformat(self, revstr):
+    def checkrevformat(self, revstr, mapname='splicemap'):
         """ Mercurial, revision string is a 40 byte hex """
-        self.checkhexformat(revstr)
+        self.checkhexformat(revstr, mapname)
diff --git a/hgext/convert/subversion.py b/hgext/convert/subversion.py
--- a/hgext/convert/subversion.py
+++ b/hgext/convert/subversion.py
@@ -454,13 +454,13 @@ class svn_source(converter_source):
         del self.commits[rev]
         return commit
 
-    def checkrevformat(self, revstr):
+    def checkrevformat(self, revstr, mapname='splicemap'):
         """ fails if revision format does not match the correct format"""
         if not re.match(r'svn:[0-9a-f]{8,8}-[0-9a-f]{4,4}-'
                               '[0-9a-f]{4,4}-[0-9a-f]{4,4}-[0-9a-f]'
                               '{12,12}(.*)\@[0-9]+$',revstr):
-            raise util.Abort(_('splicemap entry %s is not a valid revision'
-                               ' identifier') % revstr)
+            raise util.Abort(_('%s entry %s is not a valid revision'
+                               ' identifier') % (mapname, revstr))
 
     def gettags(self):
         tags = {}