templater: add subsetparents(rev, revset) function Naming suggestions are welcome. And this could be flagged as an (ADVANCED) function since the primary use case is to draw a graph. This provides all data needed for drawing revisions graph filtered by revset, and allows us to implement a GUI graph viewer in some languages better than Python. A frontend grapher will be quite similar to our graphmod since subsetparents() just returns parent-child relations in the filtered sub graph. Frontend example: https://hg.sr.ht/~yuja/hgv/browse/default/core/hgchangesetgrapher.cpp However, the resulting graph will be simpler than the one "hg log -G" would generate because redundant edges are eliminated. This should be the same graph rendering strategy as TortoiseHg. This function could be implemented as a revset predicate, but that would mean the scanning state couldn't be cached and thus slow. Test cases are split to new file since test-template-functions.t is quite big and we'll need a new branchy repository anyway.

templater: remember cache key of evaluated revset This provides a hint for caching further computation result of the given revset. See the next patch for example.

templater: fix cbor() filter to accept smartset So the wrapper type can return a bare smartset.

templater: introduce wrapper for smartset (API) I want to add a template function which takes a revset as an argument: {somefunc(..., revset(...))} ^^^^^^^^^^^ evaluates to a revslist This wrapper will provide a method to get an underlying smartset. It should also be good for performance since count(revset(...)) will no longer have to fully consume the smartset for example, but that isn't the point of this change.

setup: build C extensions with -Werror=declaration-after-statement MSVC 2008 still needs declarations at the top of the scope. I added it to the 3rd party code too in case somebody vendors a new version with a problem- they'll get an early warning. Clang seems to ignore this (at least on 10.14 with Xcode 10), and gcc 7.4 will error out as desired on Ubuntu 18.04. Thanks to Yuya for remembering the name of the option. Differential Revision: https://phab.mercurial-scm.org/D8318

merge with stable

osutil: move declaration to top of the scope Otherwise the build would fail with -Werror=declaration-after-statement.

phabricator: remove *-argument from _getdrevs() It can't take more than one specs arguments per len(*specs).

revset: leverage internal _rev() function to implement rev() Now 'rev(n)' is identical to 'present(_rev(n))'.

revset: fix crash by repo.revs('%d', tip + 1) IndexError shouldn't be raised from a revset predicate. The error message is copied from scmutil.revsymbol().