diff --git a/hgext/convert/cvsps.py b/hgext/convert/cvsps.py
--- a/hgext/convert/cvsps.py
+++ b/hgext/convert/cvsps.py
@@ -239,12 +239,12 @@ def createlog(ui, directory=None, root="
                 continue
             match = re_01.match(line)
             if match:
-                raise Exception(match.group(1))
+                raise logerror(match.group(1))
             match = re_02.match(line)
             if match:
-                raise Exception(match.group(2))
+                raise logerror(match.group(2))
             if re_03.match(line):
-                raise Exception(line)
+                raise logerror(line)
 
         elif state == 1:
             # expect 'Working file' (only when using log instead of rlog)
diff --git a/mercurial/pure/mpatch.py b/mercurial/pure/mpatch.py
--- a/mercurial/pure/mpatch.py
+++ b/mercurial/pure/mpatch.py
@@ -112,7 +112,7 @@ def patchedsize(orig, delta):
         outlen += length
 
     if bin != binend:
-        raise Exception("patch cannot be decoded")
+        raise ValueError("patch cannot be decoded")
 
     outlen += orig - last
     return outlen