tests: use context manager form of assertRaises Support for using unittest.TestCase.assertRaises as a context manager was added in Python 2.7. This form is more readable, especially for complex tests. While I was here, I also restored the use of assertRaisesRegexp, which was removed in c6921568cd20 for Python 2.6 compatibility.

obsolete: use 2 argument form of enumerate() The 2 argument form of enumerate was added in Python 2.6. This change effectively reverts 10880c8aad85.

tests: remove special handling for undefined memoryview 'memoryview' was introduced in Python 2.7. 4adc090fa2fb added code to filterpyflakes.py to ignore "undefined name 'memoryview'" pyflakes warnings. Since we no longer support <Python 2.7, we can remove this workaround.

encoding: remove workaround for locale.getpreferredencoding() locale.getpreferredencoding() was buggy in OS X for Python <2.7. Since we no longer support Python <2.7, we no longer need this workaround. This essentially reverts 2be70ca17311.

mail: remove code to support < Python 2.7 This code was added in 594b98846ce1. Since we no longer support Python <2.7, it can be removed.

help: clarify that colons are allowed in fingerprints values This was suggested by Lars Rohwedder in issue5559.

sslutil: tweak the legacy [hostfingerprints] warning message Lars Rohwedder noted in issue5559 that the previous wording was confusing. I agree.

rebase: allow rebase even if some revisions need no rebase (BC) (issue5422) This allows you to do e.g. "hg rebase -d @ -r 'draft()'" even if some drafts are already based off of @. You'd still need to exclude obsolete and troubled revisions, though. We will deal with those cases later. Implemented by treating state[rev]==rev as "no need to rebase". I considered adding another fake revision number like revdone=-6. That would make the code clearer in a few places, but would add extra code in other places. I moved the existing test out of test-rebase-base.t and into a new file and added more tests there, since not all are using --base.

chgserver: more explicit about sensitive environ variables Environment variables like HGUSER, HGEDITOR, HGEDITFROM should not trigger a new chgserver. This patch uses a whitelist for environ variables starting with "HG" to reduce the number of servers. I have went through `grep -o "[\"']HG[A-Z_0-9]*['\"]" -hR . | sort -u` so the list should be up-to-date.

scmutil: make simplekeyvaluefile able to have a non-key-value first line To ease migration from files with version numbers in their first lines, we want simplekeyvaluefile to support a non-key-value first line. In this way, old versions of Mercurial will read such files, discover a newer version than the one they know how to handle and fail gracefully, rather than with exception. Shelve's shelvestate file is an example.