[PATCH 1 of 8] formatter: more details on assertion failure

[Boris Feld]

# HG changeset patch
# User Boris Feld <boris.feld at octobus.net>
# Date 1538408273 -7200
#      Mon Oct 01 17:37:53 2018 +0200
# Node ID 8eaff9311fa407d89854d6e60938200939a0a506
# Parent  a66594c5fad422499bfaf669d182e02fe3c0be32
# EXP-Topic revlog-perf
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 8eaff9311fa4
formatter: more details on assertion failure

This is useful when the assertion fails.

diff --git a/mercurial/formatter.py b/mercurial/formatter.py
--- a/mercurial/formatter.py
+++ b/mercurial/formatter.py
@@ -213,7 +213,7 @@ class baseformatter(object):
     def write(self, fields, deftext, *fielddata, **opts):
         '''do default text output while assigning data to item'''
         fieldkeys = fields.split()
-        assert len(fieldkeys) == len(fielddata)
+        assert len(fieldkeys) == len(fielddata), (fieldkeys, fielddata)
         self._item.update(zip(fieldkeys, fielddata))
     def condwrite(self, cond, fields, deftext, *fielddata, **opts):
         '''do conditional write (primarily for plain formatter)'''