journal: use the dirstate parentchange callbacks Instead of hacking into dirstate internals let's use the callbacks to be notified about wd parent change.

dirstate: add callback to notify extensions about wd parent change The journal extension had to touch the dirstate internals to be notified about wd parent change. To make that detection cleaner and reusable let's move it core. Now the extension can register to be notified about parent changes.

revpair: do not optimize tree to check for odd-range spec At cc3a30ff9490, we had to optimize a parsed tree to resolve x^:y ambiguity. Since we've moved the resolution of x^:y to parse(), we no longer have to call optimize(). Therefore, (x:y) can be taken as a single expression, not an odd range expression x:y.

revset: also parse x^: as (x^): Given x^:y is (x^):y, this seems sensible.

revset: resolve ambiguity of x^:y before alias expansion This is purely a parsing problem, which should be resolved before alias expansion.

revset: add test for resolution of infix/suffix ambiguity of x^:y This is the test for 805651777188, and I'm going to fix the failure of 'x^A' where 'revsetalias.A=:y'.

parser: remove unused binding parameter from suffix action Because a suffix action never takes subsequent tokens, it should have no binding strength nor closing character. I've tried if this value could be used to resolve infix/suffix ambiguity of x^:y, but it appears not. So I decided to resend this patch.

revset: fix keyword arguments to go through optimization process Before, a keyvalue node was processed by the last catch-all condition of _optimize(). Therefore, topo.firstbranch=expr would bypass tree rewriting and would crash if an expr wasn't trivial.

extensions: add unwrapfunction to undo wrapfunction Before this patch, we don't have a safe way to undo a wrapfunction because other extensions may wrap the same function and calling setattr will undo them accidentally. This patch adds an "unwrapfunction" to address the issue. It removes the wrapper from the wrapper chain, and re-wraps everything, which is not the most efficient but short and easy to understand. We can revisit the code if we have perf issues with long chains. The "undo" feature is useful in cases like wrapping a function just in a scope. Like, having a "select" command to interactively (using arrow keys) select content from some output (ex. smartlog). It could wrap "ui.label" to extract interesting texts just in the "select" command.

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