demandimport: support "absolute_import" for external libraries (issue4029) Before this patch, demandimport of Mercurial may fail to load external libraries using "from __future__ import absolute_import": for example, importing "foo" in "bar.baz" module will load "bar.foo" if it exists, even though "absolute_import" is enabled in "bar.baz" module. So, extensions for Mercurial can't use such external libraries. This patch saves "level" of import request for on-demand module loading in the future: default value of level is -1, and level is 0 when "absolute_import" is enabled. "level" value is passed to built-in import function in "_demandmod._load()" and it should load target module correctly. This patch changes only one "_demandmod" construction case other than cases below: - construction in "_demandmod._load()" this code path should be used only in relative sub-module loading case - constructions other than patched one in"_demandimport()" these code paths shouldn't be used in "level != -1" case

hghave: add "py3k" feature to check whether test runs with Python 3.x This patch adds "py3k" feature to check whether test runs with Python 3.x. This check is needed for portability of test code: for example, in the default, modules are imported relatively first with python 2.x, but imported absolutely with Python 3.x.

hghave: add "absimport" feature to check "absolute_import" in __future__ This patch adds "absimport" feature to check whether "absolute_import" exists in __future__, which means supporting module loading by absolute name. This check is needed for portability of test code using "absolute_import", because Python earlier than 2.5 doesn't support it.

merge: exit early during a no-op update (BC) hg update . (or equivalents) are effectively no-ops in just about all circumstances. These sorts of updates can be especially common in a bookmark-oriented workflow. This saves us a status check and a manifest decompression, which means that on a repo with over 210,000 files, this brings hg update . down from 2.5 seconds to 0.15. There is one change in behavior: a file that was added, not committed, and then deleted but not removed used to be removed from the dirstate. With this patch it isn't. This is what causes the change in test-mq-qpush-exact.t. This seems like it's enough of an edge case to not be worth handling. The output of test-empty.t changes because those files are not yet created.

localrepo: invoke only feature setup functions for enabled extensions Before this patch, each feature setup functions for localrepository class should examine whether corresponding extension is enabled or not by themselves. This patch invokes only feature setup functions defined in module of enabled extensions, and it makes implementation of feature setup functions easier and simpler.

lock: handle race in trylock/testlock on Windows readlock may raise IOError if the system does not support symlink.

rebase: preserve active bookmark when not at head (issue3813) Now that the working directory parent is preserved, we can preserve the active bookmark too.

rebase: preserve working directory parent (BC) Prior to this changeset, rebase always left the working directory as a parent of the last rebased changeset. The is dubious when, before the rebase, the working directory was not a parent of the tip most rebased changeset. With this changeset, we move the working directory back to its original parent. If the original parent was rebased, we use it's successors. This is a step toward solving issue3813 (rebase loses active bookmark if it's not on a head)