walkchangerevs: replace try/except with 'next' Again, this make the code clearer.

generatorset: use 'next()' to simplify the code The 'next()' built-in accept a default value. This remove the needs to check if self non-empty before returning a value.

revset: use 'next()' to detect end of iteration in 'last' The 'next()' built-in can return a default value, allow to get rid of the confusing try/except code flow.

revset: use 'next()' to detect end of iteration in 'limit' The 'next()' built-in can return a default value, allow to get rid of the confusing try/except code flow.

_revancestors: use 'next' to remove the verbose try except clauses The 'next()' built-in can return a default value, making the final iteration case simpler and clearer.

check-code: lift the ban on 'next()' 'next' is supported by Python2.6 the new lowest version supported by Mercurial.

check-code: drop the 'isdisjoint' ban 'isdisjoint' is available in Python 2.6. The new lowest supported version.

check-code: fix the error message about 'class foo():' Using 'classs foo():' result in old style object instead of new style object. We do not want old style object so this check is unrelated to 2.4.

check-code: remove the check for os.path.relpath This is available in Python2.6 the new default supported release.

patch: remove duplicated import of cStringIO It is already imported a couple of line above.