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.