revset: move order constants from revsetlang Thanks to the recent refactor, the ordering rule is fully processed at runtime.

tag: use filtered repo when creating new tags (issue5539) When pruning a changeset that added a tag and then adding another tag, the "pruned" tag gets restored. This is because the tag creation step (tags._tag() call in tags.tag()) is currently done on the unfiltered repo. This behavior has been there from 7977d35df13b which backs out b08af8f0ac01 with no clear reason but caution on unthought situations at that time. In this changeset, we pass the filtered repo to tags._tag(), preventing "pruned" tags to reappear. This somehow restores b08af8f0ac01, though now we arguably have a valid use case for.

extensions: add wrappedfunction() context manager Several extensions exist that temporarily want to wrap a function (at least narrowhg, any many of the extensions in hg-experimental). That's why we have the unwrapfunction() that was introduced in 19578bb84731 (extensions: add unwrapfunction to undo wrapfunction, 2016-08-10). This patch adds a simple wrappedfunction() that returns a context manager. Differential Revision: https://phab.mercurial-scm.org/D472