extensions: add getwrapperchain to get a list of wrappers The getwrapperchain returns a list of wrappers + the original function, making it easier to understand what has been wrapped by whom. For example: In : mercurial.extensions.getwrapperchain(mercurial.dispatch, '_runcommand') Out: [<function hgext.pager.pagecmd>, <function hgext.color.colorcmd>, <function hgext.zeroconf.cleanupafterdispatch>, <function mercurial.dispatch._runcommand>] It will also be useful to safely unwrap a function. See the next patch.

extensions: set attributes to wrappers so we can trace them back This patch adds two attributes about the original function and the unbound wrapper. It allows us to get a chain of wrappers. See the next patch.

ui: drop values returned by inspect.*frame*() to avoid cycles "f = inspect.currentframe()" instantly creates a cycle because "f.f_locals['f']" is "f" itself. This patch explicitly sets those frame objects to None to avoid cycles.

dispatch: split global error handling out so it can be reused We may want a similar error handling at worker.py. This patch extracts the error handling logic to "callcatch" so it can be reused.

py3: conditionalize _winreg import _winreg module is renamed to winreg in python 3. Added the conditionalize statements in the respective file because adding this in pycompat will result in pycompat throwing error as this is a windows registry module and we have buildbots and most of the contributors on linux.

py3: conditionalize the raise statement raise E,V,T is not acceptable in Python 3, thats is conditionalized. Moreover this will result in syntax error so we have to use exec() to execute this. Related PEP- https://www.python.org/dev/peps/pep-3109/#id14 My implementation is motivated from the six implementation except they are defining a new function exec_() to prevent adding an extra frame AFAIK :) https://bitbucket.org/gutworth/six/src/ca4580a5a648/six.py#six.py-680

match: added matchessubrepo method to matcher Previously there were three local implementations of this function in cmdutil.files, cmdutil.remove and scmutil.addremove.

changegroup: move branch cache debug message to proper location Before, we logged about performing a branch cache update when we weren't actually doing it. Fix that.